1. The study investigated factors influencing body size in bumblebees (Bombus terrestris).
2. An experiment found that worker body size increased with colony age, confirming previous results.
3. A cross-fostering experiment found that eggs developed into adults similar in size to unrelated nestmates, not full sisters, indicating environmental factors rather than internal egg factors determine size.
This study examined the relationship between wing wear and thorax weight as a method of aging bumblebees in two species: Bombus monticola and Bombus pratorum found in Ireland and Northern Ireland. The study found a clear positive relationship between thorax weight and wing perimeter, with larger thorax weights correlated with longer wing perimeters. However, after accounting for the influence of thorax weight, the existing wing wear scale did not accurately assess age for these two bumblebee species.
Depopulation options as welfare indicator for layer systemsHarm Kiezebrink
Egg production systems have become subject to heightened levels of scrutiny. Multiple factors such as disease, skeletal and foot health, pest and parasite load, behavior, stress, affective states, nutrition, and genetics influence the level of welfare hens experience. Although the need to evaluate the influence of these factors on welfare is recognized, research is still in the early stages.
In this paper conventional cages are compared to furnished cages, non-cage systems, and outdoor systems. Specific attributes of each system are shown to affect welfare, and systems that have similar attributes are affected similarly.
Environments such as conventional cages, which limit movement, can lead to osteoporosis, but environments that have increased complexity, such as non-cage systems, expose hens to an increased incidence of bone fractures.
Less is understood about the stress that each system imposes on the hen, but it appears that each system has its unique challenges. Selective breeding for desired traits such as improved bone strength and decreased feather pecking and cannibalism may help to improve welfare.
It appears that no single housing system is ideal from a hen welfare perspective. Although environmental complexity increases behavioral opportunities, it also introduces difficulties in terms of disease and pest control.
One specific circumstance has not been taken into consideration in this paper: how to depopulate the hens in case of an outbreak situation. Emergency control is not an economic parameter to choose a specific production system, but comparing a production system with or without cages, it is clear that it is much easier to depopulate chickens in a system without cages. Without a proper technique to cull the animals in a animal welfare friendly way and to transport the carcasses out of the house mechanically, the chickens are killed and transported manually.
This is not only increasing the risks for humans to get infected, it also influences the risks that animals suffer unnecessary during depopulation. Handling animals during outbreak situations is mostly done by inexperienced responders who have little to no knowledge about animal welfare. Veterinary authorities in charge of the response activities have issues like effectiveness and efficiency to consider.
How to depopulate the chickens in an outbreak situation is an important welfare indicator and the producer of these systems need to be kept responsible for the technical solution.
Harm Kiezebrink
Research Fellow Queensland University /
CEO AVT Europe AB
AVT Applied Veterinary Technologies Europe AB
Address details: c/o INTRED, Södra Hamnen 2,
45142 Uddevalla, Sweden
Phone: +44 7452 272 358
E-mail: harm.kie@gmail.com
It was observed that swim rate of sperm changes in microgravity. Sperm swim with higher velocity in microgravity. The fertilization might be affected by this mobility changes in sperm and this led to reduction in sperm motility under microgravity. Follicle Stimulating Hormone FSH that is responsible for ovulation in women by triggering egg maturity and stimulating sperm production in men can be damaged by microgravity. Therefore, ovulations and triggering of egg maturity and production of sperm may not take place. Higher acidity of outer vagina due to fluid distribution at the upper part of the body might kill the sperm or reduce sperm counts. Microgravity environment reduced the thickening of the endometrium to the extent that eggs cannot be planted cause non implantations . Jaiyeola O. Paul | Oluwafemi A. Funmilola | Abdullahi S. Ayegba "Microgravity and Infertility" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-3 | Issue-6 , October 2019, URL: https://www.ijtsrd.com/papers/ijtsrd29408.pdf Paper URL: https://www.ijtsrd.com/other-scientific-research-area/other/29408/microgravity-and-infertility/jaiyeola-o-paul
This document discusses the technoscientific controversy surrounding genetically modified (GM) foods. It begins by exploring the blurred lines between what is considered natural versus artificial when it comes to GM foods. While gene splicing is an artificial process, the resulting GM crops appear natural and can reproduce naturally. The document then examines whether GM foods can be considered a success or failure. While most research finds GM foods safe for human consumption and the environment, some studies have found potential risks to human and environmental health. There is no clear consensus on whether GM foods are an overall success or failure due to differing worldviews and definitions of those terms.
Biology is the study of life through the science of living things. It examines the characteristics of life including cellular composition, growth, reproduction, movement, adaptation, metabolism, specific organization, homeostasis, and responsiveness. Cells are the basic unit of structure and function, and organisms can be unicellular or multicellular. Reproduction can occur asexually through cell division or sexually through the union of sex cells. Adaptation allows organisms to change to meet environmental needs through behavioral, physiological, and structural modifications. Metabolism converts food to energy through chemical reactions while homeostasis maintains stable internal conditions.
This document discusses the gut microbiome and its links to cognitive disorders. It aims to provide an overview of the gut microbiome, the gut-brain axis, and how gut microbes can affect central nervous system function and development. It discusses research showing links between gut microbiota and disorders like autism, depression, and schizophrenia. Current and potential future treatments are explored that aim to target the gut microbiome for mental health disorders.
This document summarizes research on the evolution of body size and sexual size dimorphism in two Galapagos species: the marine iguana and flightless cormorant. For marine iguanas, body size varies between islands and is influenced by sexual selection for larger males and natural selection pressures like El Nino events. Larger males are more successful in mating. For flightless cormorants, the cause of sexual size dimorphism is less clear but may be due to differing ecological pressures on males and females rather than sexual selection. The evolution of size is complex and varies between species depending on environmental and social factors.
The document summarizes research on the gut microbiome and its relationship to obesity and non-alcoholic fatty liver disease (NAFLD). It reviews how the microbiome is influenced by factors from birth and can impact disease risk. Studies show differences in microbiome composition between obese, normal weight, and NAFLD patients, with NAFLD patients having higher levels of Escherichia bacteria that can produce alcohol. A pilot study found that treating pediatric NAFLD patients with the probiotic Lactobacillus GG for 8 weeks improved liver enzymes regardless of weight changes. Further research is still needed to fully understand the mechanisms and potential microbiome-based therapies.
This study examined the relationship between wing wear and thorax weight as a method of aging bumblebees in two species: Bombus monticola and Bombus pratorum found in Ireland and Northern Ireland. The study found a clear positive relationship between thorax weight and wing perimeter, with larger thorax weights correlated with longer wing perimeters. However, after accounting for the influence of thorax weight, the existing wing wear scale did not accurately assess age for these two bumblebee species.
Depopulation options as welfare indicator for layer systemsHarm Kiezebrink
Egg production systems have become subject to heightened levels of scrutiny. Multiple factors such as disease, skeletal and foot health, pest and parasite load, behavior, stress, affective states, nutrition, and genetics influence the level of welfare hens experience. Although the need to evaluate the influence of these factors on welfare is recognized, research is still in the early stages.
In this paper conventional cages are compared to furnished cages, non-cage systems, and outdoor systems. Specific attributes of each system are shown to affect welfare, and systems that have similar attributes are affected similarly.
Environments such as conventional cages, which limit movement, can lead to osteoporosis, but environments that have increased complexity, such as non-cage systems, expose hens to an increased incidence of bone fractures.
Less is understood about the stress that each system imposes on the hen, but it appears that each system has its unique challenges. Selective breeding for desired traits such as improved bone strength and decreased feather pecking and cannibalism may help to improve welfare.
It appears that no single housing system is ideal from a hen welfare perspective. Although environmental complexity increases behavioral opportunities, it also introduces difficulties in terms of disease and pest control.
One specific circumstance has not been taken into consideration in this paper: how to depopulate the hens in case of an outbreak situation. Emergency control is not an economic parameter to choose a specific production system, but comparing a production system with or without cages, it is clear that it is much easier to depopulate chickens in a system without cages. Without a proper technique to cull the animals in a animal welfare friendly way and to transport the carcasses out of the house mechanically, the chickens are killed and transported manually.
This is not only increasing the risks for humans to get infected, it also influences the risks that animals suffer unnecessary during depopulation. Handling animals during outbreak situations is mostly done by inexperienced responders who have little to no knowledge about animal welfare. Veterinary authorities in charge of the response activities have issues like effectiveness and efficiency to consider.
How to depopulate the chickens in an outbreak situation is an important welfare indicator and the producer of these systems need to be kept responsible for the technical solution.
Harm Kiezebrink
Research Fellow Queensland University /
CEO AVT Europe AB
AVT Applied Veterinary Technologies Europe AB
Address details: c/o INTRED, Södra Hamnen 2,
45142 Uddevalla, Sweden
Phone: +44 7452 272 358
E-mail: harm.kie@gmail.com
It was observed that swim rate of sperm changes in microgravity. Sperm swim with higher velocity in microgravity. The fertilization might be affected by this mobility changes in sperm and this led to reduction in sperm motility under microgravity. Follicle Stimulating Hormone FSH that is responsible for ovulation in women by triggering egg maturity and stimulating sperm production in men can be damaged by microgravity. Therefore, ovulations and triggering of egg maturity and production of sperm may not take place. Higher acidity of outer vagina due to fluid distribution at the upper part of the body might kill the sperm or reduce sperm counts. Microgravity environment reduced the thickening of the endometrium to the extent that eggs cannot be planted cause non implantations . Jaiyeola O. Paul | Oluwafemi A. Funmilola | Abdullahi S. Ayegba "Microgravity and Infertility" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-3 | Issue-6 , October 2019, URL: https://www.ijtsrd.com/papers/ijtsrd29408.pdf Paper URL: https://www.ijtsrd.com/other-scientific-research-area/other/29408/microgravity-and-infertility/jaiyeola-o-paul
This document discusses the technoscientific controversy surrounding genetically modified (GM) foods. It begins by exploring the blurred lines between what is considered natural versus artificial when it comes to GM foods. While gene splicing is an artificial process, the resulting GM crops appear natural and can reproduce naturally. The document then examines whether GM foods can be considered a success or failure. While most research finds GM foods safe for human consumption and the environment, some studies have found potential risks to human and environmental health. There is no clear consensus on whether GM foods are an overall success or failure due to differing worldviews and definitions of those terms.
Biology is the study of life through the science of living things. It examines the characteristics of life including cellular composition, growth, reproduction, movement, adaptation, metabolism, specific organization, homeostasis, and responsiveness. Cells are the basic unit of structure and function, and organisms can be unicellular or multicellular. Reproduction can occur asexually through cell division or sexually through the union of sex cells. Adaptation allows organisms to change to meet environmental needs through behavioral, physiological, and structural modifications. Metabolism converts food to energy through chemical reactions while homeostasis maintains stable internal conditions.
This document discusses the gut microbiome and its links to cognitive disorders. It aims to provide an overview of the gut microbiome, the gut-brain axis, and how gut microbes can affect central nervous system function and development. It discusses research showing links between gut microbiota and disorders like autism, depression, and schizophrenia. Current and potential future treatments are explored that aim to target the gut microbiome for mental health disorders.
This document summarizes research on the evolution of body size and sexual size dimorphism in two Galapagos species: the marine iguana and flightless cormorant. For marine iguanas, body size varies between islands and is influenced by sexual selection for larger males and natural selection pressures like El Nino events. Larger males are more successful in mating. For flightless cormorants, the cause of sexual size dimorphism is less clear but may be due to differing ecological pressures on males and females rather than sexual selection. The evolution of size is complex and varies between species depending on environmental and social factors.
The document summarizes research on the gut microbiome and its relationship to obesity and non-alcoholic fatty liver disease (NAFLD). It reviews how the microbiome is influenced by factors from birth and can impact disease risk. Studies show differences in microbiome composition between obese, normal weight, and NAFLD patients, with NAFLD patients having higher levels of Escherichia bacteria that can produce alcohol. A pilot study found that treating pediatric NAFLD patients with the probiotic Lactobacillus GG for 8 weeks improved liver enzymes regardless of weight changes. Further research is still needed to fully understand the mechanisms and potential microbiome-based therapies.
1) The study analyzed data from over 1,000 Western adults and found evidence that some taxa in the human gut microbiome exist in alternative stable states, shifting between high and low abundance profiles.
2) Specifically, around 10% of prevalent taxa showed bimodal abundance distributions and reduced stability at intermediate abundances, indicating bi-stability.
3) These bi-stable "tipping elements" can co-occur in different combinations and have been linked to metabolic syndrome and inflammatory bowel disease.
Mapping the Human Gut Microbiome in Health and Disease Using Sequencing, Supe...Larry Smarr
Invited Talk Delivered by Mehrdad Yazdani, Calit2 Ayasdi Sponsored Lunch & Learn American Society of Human Genetics (ASHG) San Diego Convention Center October 19, 2014
This document reports on a study that examined the relationship between bacterial diversity and primary productivity in aquatic mesocosms designed to mimic small ponds. The key findings were:
1) Bacterial richness, as estimated by sequencing 16S rDNA from samples, varied along the gradient of primary productivity created by altering nutrient inputs in the mesocosms.
2) Different bacterial taxonomic groups (Cytophaga-Flavobacteria-Bacteroides, Alpha-proteobacteria, Beta-proteobacteria) exhibited different relationships between richness and productivity - hump shaped, U-shaped, and no relationship, respectively.
3) This is one of the first studies to demonstrate that bacterial diversity
Ethical issues related to transgenic animalsmahathiviji
This document discusses the ethical issues related to transgenic animals. It begins by defining ethics, bioethics, and the two types of genetic modification - altering genes normally present or transferring genes between individuals. Genetic modification of animals is used to help research human diseases, develop new drugs, provide transplant tissues/organs, and enhance livestock. However, this raises ethical concerns like unpredictable ecosystem impacts, animal welfare issues, risks to human and environmental health, "playing God", and religious concerns over gene transfers between species. The document also discusses regulation bodies like GEAC and issues around patents and biopiracy of genetically modified organisms.
Dr. Andres Gomez - Microbiome studies in swine systems: challenges and opport...John Blue
Microbiome studies in swine systems: challenges and opportunities - Dr. Andres Gomez, from the 2018 Allen D. Leman Swine Conference, September 15-18, 2018, St. Paul, Minnesota, USA.
More presentations at http://www.swinecast.com/2018-leman-swine-conference-material
This document discusses the relationships between human nutrition, the gut microbiome, and the immune system. It argues that understanding how diet influences the gut microbiome and immune system could help address global health problems like malnutrition. The marriage of metagenomic methods to study the gut microbiome and gnotobiotic methods using germ-free animals could provide insights into these relationships and help test hypotheses. Dietary patterns are changing worldwide due to various social and economic factors, and understanding how these changes impact the gut microbiome may provide clues about nutritional status and immune function.
Science Cabaret by Dr. Rodney Dietert "How to train your super organism..via ...Kitty Gifford
This document summarizes a presentation by Rodney Dietert on training the human-microbial superorganism. It discusses how Dietert found his superorganism through research linking the microbiome to health and disease. He learned that humans are majority microbial and the microbiome helps produce our identity through volatile compounds. Microbial dysbiosis can lead to inflammation and disease. Dietert trained his own superorganism after years of antibiotics by adjusting his microbiome and diet. He provides three takeaway points on the importance of microbiome seeding at birth, co-maturation of the immune and microbial systems, and basing safety assessments on the human superorganism.
High-Throughput Sequencing of the Human Microbiome, Rob Knight Research Group...Copenhagenomics
The document discusses high-throughput sequencing techniques for analyzing human microbiome samples. It provides examples of studies that used these techniques to analyze microbiome samples from various body sites and populations. These studies characterized differences in microbial communities between body sites, tracked changes over time, identified correlations with disease markers, and compared communities across geographic locations and diets. Advanced analysis tools like QIIME and UniFrac were highlighted for interpreting vast amounts of sequencing data from hundreds of microbiome samples.
1. Evolution occurs as populations of organisms adapt to their environments over generations through natural selection.
2. Variation within populations is caused by mutations and sexual reproduction, providing variation for natural selection to act upon.
3. Charles Darwin's theory of evolution by natural selection proposed that species change over time as individuals better adapted to their environments are more likely to survive and pass on their genes.
This document discusses the evolution of parental care and ovulation behavior in oysters. It presents competing hypotheses about the ancestral state and direction of evolution in these traits. The study constructs molecular phylogenetic trees including representatives of all three ostreid subfamilies to test these hypotheses. The results indicate that broadcast spawning was ancestral, brooding evolved once in a common ancestor and has been retained, and the unusual ovulation behavior predates the evolution of parental care in oysters.
Friend or Foe: The Microbiome in Autoimmunity DrBonnie360
Content and Visual Design by Tiffany Simms
DrBonnie360 presents The Microbiome: Sorting the Hype from the Hope at Cambridge Healthtech Institute's 23rd International Molecular Med TRI-CON 2016 in San Francisco, March 6, 2016.
Bringing two scientists from the Sonnenburg and Knight Lab, and four microbiome companies, DrBonnie360 moderates a short course on all you need to know about the microbiome and whether it will be your best friend or your worst enemy.
As DrBonnie360's work surrounds autoimmune diseases, the microbiome proves to be one of the lifelines autoimmunity could use to cross the autoimmune abyss. Presented in this slideshare is a carefully curated set of research on autoimmune and the microbiome.
This document summarizes key concepts in ecology including habitats, abiotic factors, energy, temperature regulation, population growth, population regulation, interspecific interactions such as competition and symbiosis, communities, food webs, and ecological problems caused by human activities. It discusses how ecology is the study of relationships between organisms and their environment, outlines abiotic factors like temperature and moisture, and covers population concepts such as carrying capacity and logistic growth. Interspecific interactions like predation, competition, and symbiosis are defined. The document also briefly discusses ecological problems including pollution, resource depletion, and threats to biodiversity.
This document discusses key concepts in population biology and ecology. It begins by explaining that all life on Earth is interconnected and that human actions can significantly impact ecosystems. It then defines key population characteristics like number, density, age structure, and survival curves. The document discusses how factors like body size, life expectancy, birth and death rates, resource availability, sex ratios, and reproductive timing influence population dynamics. Overall, it provides an overview of population ecology concepts like limiting factors, carrying capacity, and relationships between populations and their environments.
This chapter discusses evolution and gene frequencies in populations. A population is a group of individuals of the same species that occupy an area and share genes. The gene pool is the sum of all alleles in a population. Factors like genetic drift, founder effects, bottlenecks, and mutations can influence gene frequencies over time independent of natural selection. The Hardy-Weinberg theorem states that allele frequencies remain stable between generations under certain conditions. Natural selection can operate through directional, disruptive, or stabilizing selection and influence evolution. Speciation occurs when reproductive isolation develops between populations.
Your microbiome may be key factor determining your health and longevitykirti betai
1. Your gut microbiome plays a key role in your health and longevity. A healthy microbiome can help prevent diseases like inflammatory bowel disease and diabetes, while an unhealthy one allows disease to take hold.
2. Certain bacteria in the gut, like Faecalibacterium prausnitzii, appear to have anti-inflammatory properties that can protect against conditions like Crohn's disease. Maintaining a diverse population of beneficial microbes is important for immune function.
3. Widespread antibiotic overuse has fueled deadly infections like Clostridium difficile, which causes life-threatening diarrhea. C. difficile infections are especially prevalent in hospitals and nursing homes.
Diet Dominates Host Genotype in Shaping the Murine Gut MicrobiotaAlireza Kashani
Diet has a significant impact on shaping the gut microbiota composition according to this study. Researchers found that placing mice on different diets (low-fat vs high-fat/high-sugar) caused their gut microbiota to cluster more by diet than by host genotype. Even for mice with the same genotype, diet dominated in determining microbiota profile. When diets were alternated, the microbiota responded rapidly but showed some lag effects. The study demonstrates the outsized role of diet relative to host genetics in shaping the gut microbiome.
This document lists published papers, book chapters, and conference abstracts by Kovacs, A. and their co-authors. It includes 8 peer-reviewed papers on topics related to the gut microbiota and its association with disease. One published book chapter discusses the intestinal microbiota and intestinal disease. Two published conference abstracts presented findings on pouch inflammation and differences in the intestinal microbiota between Crohn's disease subtypes.
Deal: Samsung Galaxy S23 Ultra can be yours with up to RM1,500 discount today
BY Sharil Abdul Rahman
25 September 2023
12:05 pm
Comment
Thinking of getting a Samsung flagship? We just spotted a sale for the Samsung Galaxy S23 Ultra on Shopee, with a huge RM 1,500 discount. For a 2023 flagship, this is one of the biggest, it not the biggest,
https://youtube.com/shorts/3Vqu8Ui7Ros?si=8Crxj4OYqWBjWC5J
https://www.youtube.com/channel/UCyTZZP6faGeWWmWHHYzB4iQ
https://youtube.com/shorts/QKbAu7JcL_E?si=bi24Q9yYoDVih5tD
https://youtube.com/shorts/3Vqu8Ui7Ros?si=8Crxj4OYqWBjWC5J
https://rekonise.com/apk-o3cam
Deal: Samsung Galaxy S23 Ultra can be yours with up to RM1,500 discount today
BY Sharil Abdul Rahman
25 September 2023
12:05 pm
Comment
Thinking of getting a Samsung flagship? We just spotted a sale for the Samsung Galaxy S23 Ultra on Shopee, with a huge RM 1,500 discount. For a 2023 flagship, this is one of the biggest, it not the biggest,
Review Sperm Comparative Morphology and Function Related to Altered Reproductiveanbiocore
This document provides a review of the evolution of sperm structure and function in mammals. It discusses how sperm size, shape, and structures like flagella have diverged among species due to factors like body size, mating systems, and sperm competition. Larger mammals tend to have smaller sperm to produce more of them, while smaller mammals produce fewer but larger sperm. The review also examines how reproductive strategies around fertilization have influenced sperm traits, with species relying more on numbers favoring smaller, faster sperm and those using sperm displacement favoring fewer but more competitive sperm.
1) The study analyzed data from over 1,000 Western adults and found evidence that some taxa in the human gut microbiome exist in alternative stable states, shifting between high and low abundance profiles.
2) Specifically, around 10% of prevalent taxa showed bimodal abundance distributions and reduced stability at intermediate abundances, indicating bi-stability.
3) These bi-stable "tipping elements" can co-occur in different combinations and have been linked to metabolic syndrome and inflammatory bowel disease.
Mapping the Human Gut Microbiome in Health and Disease Using Sequencing, Supe...Larry Smarr
Invited Talk Delivered by Mehrdad Yazdani, Calit2 Ayasdi Sponsored Lunch & Learn American Society of Human Genetics (ASHG) San Diego Convention Center October 19, 2014
This document reports on a study that examined the relationship between bacterial diversity and primary productivity in aquatic mesocosms designed to mimic small ponds. The key findings were:
1) Bacterial richness, as estimated by sequencing 16S rDNA from samples, varied along the gradient of primary productivity created by altering nutrient inputs in the mesocosms.
2) Different bacterial taxonomic groups (Cytophaga-Flavobacteria-Bacteroides, Alpha-proteobacteria, Beta-proteobacteria) exhibited different relationships between richness and productivity - hump shaped, U-shaped, and no relationship, respectively.
3) This is one of the first studies to demonstrate that bacterial diversity
Ethical issues related to transgenic animalsmahathiviji
This document discusses the ethical issues related to transgenic animals. It begins by defining ethics, bioethics, and the two types of genetic modification - altering genes normally present or transferring genes between individuals. Genetic modification of animals is used to help research human diseases, develop new drugs, provide transplant tissues/organs, and enhance livestock. However, this raises ethical concerns like unpredictable ecosystem impacts, animal welfare issues, risks to human and environmental health, "playing God", and religious concerns over gene transfers between species. The document also discusses regulation bodies like GEAC and issues around patents and biopiracy of genetically modified organisms.
Dr. Andres Gomez - Microbiome studies in swine systems: challenges and opport...John Blue
Microbiome studies in swine systems: challenges and opportunities - Dr. Andres Gomez, from the 2018 Allen D. Leman Swine Conference, September 15-18, 2018, St. Paul, Minnesota, USA.
More presentations at http://www.swinecast.com/2018-leman-swine-conference-material
This document discusses the relationships between human nutrition, the gut microbiome, and the immune system. It argues that understanding how diet influences the gut microbiome and immune system could help address global health problems like malnutrition. The marriage of metagenomic methods to study the gut microbiome and gnotobiotic methods using germ-free animals could provide insights into these relationships and help test hypotheses. Dietary patterns are changing worldwide due to various social and economic factors, and understanding how these changes impact the gut microbiome may provide clues about nutritional status and immune function.
Science Cabaret by Dr. Rodney Dietert "How to train your super organism..via ...Kitty Gifford
This document summarizes a presentation by Rodney Dietert on training the human-microbial superorganism. It discusses how Dietert found his superorganism through research linking the microbiome to health and disease. He learned that humans are majority microbial and the microbiome helps produce our identity through volatile compounds. Microbial dysbiosis can lead to inflammation and disease. Dietert trained his own superorganism after years of antibiotics by adjusting his microbiome and diet. He provides three takeaway points on the importance of microbiome seeding at birth, co-maturation of the immune and microbial systems, and basing safety assessments on the human superorganism.
High-Throughput Sequencing of the Human Microbiome, Rob Knight Research Group...Copenhagenomics
The document discusses high-throughput sequencing techniques for analyzing human microbiome samples. It provides examples of studies that used these techniques to analyze microbiome samples from various body sites and populations. These studies characterized differences in microbial communities between body sites, tracked changes over time, identified correlations with disease markers, and compared communities across geographic locations and diets. Advanced analysis tools like QIIME and UniFrac were highlighted for interpreting vast amounts of sequencing data from hundreds of microbiome samples.
1. Evolution occurs as populations of organisms adapt to their environments over generations through natural selection.
2. Variation within populations is caused by mutations and sexual reproduction, providing variation for natural selection to act upon.
3. Charles Darwin's theory of evolution by natural selection proposed that species change over time as individuals better adapted to their environments are more likely to survive and pass on their genes.
This document discusses the evolution of parental care and ovulation behavior in oysters. It presents competing hypotheses about the ancestral state and direction of evolution in these traits. The study constructs molecular phylogenetic trees including representatives of all three ostreid subfamilies to test these hypotheses. The results indicate that broadcast spawning was ancestral, brooding evolved once in a common ancestor and has been retained, and the unusual ovulation behavior predates the evolution of parental care in oysters.
Friend or Foe: The Microbiome in Autoimmunity DrBonnie360
Content and Visual Design by Tiffany Simms
DrBonnie360 presents The Microbiome: Sorting the Hype from the Hope at Cambridge Healthtech Institute's 23rd International Molecular Med TRI-CON 2016 in San Francisco, March 6, 2016.
Bringing two scientists from the Sonnenburg and Knight Lab, and four microbiome companies, DrBonnie360 moderates a short course on all you need to know about the microbiome and whether it will be your best friend or your worst enemy.
As DrBonnie360's work surrounds autoimmune diseases, the microbiome proves to be one of the lifelines autoimmunity could use to cross the autoimmune abyss. Presented in this slideshare is a carefully curated set of research on autoimmune and the microbiome.
This document summarizes key concepts in ecology including habitats, abiotic factors, energy, temperature regulation, population growth, population regulation, interspecific interactions such as competition and symbiosis, communities, food webs, and ecological problems caused by human activities. It discusses how ecology is the study of relationships between organisms and their environment, outlines abiotic factors like temperature and moisture, and covers population concepts such as carrying capacity and logistic growth. Interspecific interactions like predation, competition, and symbiosis are defined. The document also briefly discusses ecological problems including pollution, resource depletion, and threats to biodiversity.
This document discusses key concepts in population biology and ecology. It begins by explaining that all life on Earth is interconnected and that human actions can significantly impact ecosystems. It then defines key population characteristics like number, density, age structure, and survival curves. The document discusses how factors like body size, life expectancy, birth and death rates, resource availability, sex ratios, and reproductive timing influence population dynamics. Overall, it provides an overview of population ecology concepts like limiting factors, carrying capacity, and relationships between populations and their environments.
This chapter discusses evolution and gene frequencies in populations. A population is a group of individuals of the same species that occupy an area and share genes. The gene pool is the sum of all alleles in a population. Factors like genetic drift, founder effects, bottlenecks, and mutations can influence gene frequencies over time independent of natural selection. The Hardy-Weinberg theorem states that allele frequencies remain stable between generations under certain conditions. Natural selection can operate through directional, disruptive, or stabilizing selection and influence evolution. Speciation occurs when reproductive isolation develops between populations.
Your microbiome may be key factor determining your health and longevitykirti betai
1. Your gut microbiome plays a key role in your health and longevity. A healthy microbiome can help prevent diseases like inflammatory bowel disease and diabetes, while an unhealthy one allows disease to take hold.
2. Certain bacteria in the gut, like Faecalibacterium prausnitzii, appear to have anti-inflammatory properties that can protect against conditions like Crohn's disease. Maintaining a diverse population of beneficial microbes is important for immune function.
3. Widespread antibiotic overuse has fueled deadly infections like Clostridium difficile, which causes life-threatening diarrhea. C. difficile infections are especially prevalent in hospitals and nursing homes.
Diet Dominates Host Genotype in Shaping the Murine Gut MicrobiotaAlireza Kashani
Diet has a significant impact on shaping the gut microbiota composition according to this study. Researchers found that placing mice on different diets (low-fat vs high-fat/high-sugar) caused their gut microbiota to cluster more by diet than by host genotype. Even for mice with the same genotype, diet dominated in determining microbiota profile. When diets were alternated, the microbiota responded rapidly but showed some lag effects. The study demonstrates the outsized role of diet relative to host genetics in shaping the gut microbiome.
This document lists published papers, book chapters, and conference abstracts by Kovacs, A. and their co-authors. It includes 8 peer-reviewed papers on topics related to the gut microbiota and its association with disease. One published book chapter discusses the intestinal microbiota and intestinal disease. Two published conference abstracts presented findings on pouch inflammation and differences in the intestinal microbiota between Crohn's disease subtypes.
Deal: Samsung Galaxy S23 Ultra can be yours with up to RM1,500 discount today
BY Sharil Abdul Rahman
25 September 2023
12:05 pm
Comment
Thinking of getting a Samsung flagship? We just spotted a sale for the Samsung Galaxy S23 Ultra on Shopee, with a huge RM 1,500 discount. For a 2023 flagship, this is one of the biggest, it not the biggest,
https://youtube.com/shorts/3Vqu8Ui7Ros?si=8Crxj4OYqWBjWC5J
https://www.youtube.com/channel/UCyTZZP6faGeWWmWHHYzB4iQ
https://youtube.com/shorts/QKbAu7JcL_E?si=bi24Q9yYoDVih5tD
https://youtube.com/shorts/3Vqu8Ui7Ros?si=8Crxj4OYqWBjWC5J
https://rekonise.com/apk-o3cam
Deal: Samsung Galaxy S23 Ultra can be yours with up to RM1,500 discount today
BY Sharil Abdul Rahman
25 September 2023
12:05 pm
Comment
Thinking of getting a Samsung flagship? We just spotted a sale for the Samsung Galaxy S23 Ultra on Shopee, with a huge RM 1,500 discount. For a 2023 flagship, this is one of the biggest, it not the biggest,
Review Sperm Comparative Morphology and Function Related to Altered Reproductiveanbiocore
This document provides a review of the evolution of sperm structure and function in mammals. It discusses how sperm size, shape, and structures like flagella have diverged among species due to factors like body size, mating systems, and sperm competition. Larger mammals tend to have smaller sperm to produce more of them, while smaller mammals produce fewer but larger sperm. The review also examines how reproductive strategies around fertilization have influenced sperm traits, with species relying more on numbers favoring smaller, faster sperm and those using sperm displacement favoring fewer but more competitive sperm.
Nasal Myiasis in animals due to Oestridae - A Mini ReviewAI Publications
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This document summarizes a study that investigated how malaria infections and prenatal testosterone exposure are correlated with the badge size of male house sparrows. The study was conducted in two regions of Camargue, France - one where mosquitoes are regularly controlled with insecticides to reduce malaria transmission, and one natural area without mosquito control. Male sparrows were caught from sites in both regions and their badge size, malaria infection status, and digit ratio (as a measure of prenatal testosterone exposure) were measured. Contrary to expectations, malaria prevalence did not differ between the two regions and was high in both. While infected birds did not have significantly different badge sizes than uninfected birds, there was a condition-dependent relationship between
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Why is it important to study reactions norms to understand phenotypi.pdfarrowmobile
Why is it important to study reactions norms to understand phenotypic plasticity?
Solution
Ans:
Phenotypic plasticity, the capacity of a single genotype to exhibit variable phenotypes in
different environments, is common in insects and is often highly adaptive. Phenotypic plasticity
is important because it expands the existing “genocentric” evolutionary theory, producing an
encompassing paradigm to explain life on earth. Plasticity was once considered “noise” but is
now widely recognized as potentially adaptive under a wide array of circumstances. As with any
major shift in scientific thinking, phenotypic plasticity engenders new ideas, causing us to ask
new questions and test hypotheses that would not otherwise be examined, leading us to
productive new scientific insights.
Phenotypic plasticity is counterbalance to mutation driven evolution: It is not surprising that
during the first half of the 20th Century, scientists, flushed with excitement about Mendelian
genetics, viewed evolution primarily as a mutational process. However, this bias largely ignored
an important reality of evolution – that natural selection selects not among genotypes, but among
phenotypes. Thus, the phenotype, and variation among phenotypes, plays a major role in
evolution. And, because the environment in which an individual develops determines its
phenotype, the environment also assumes a greater role in evolution, and may, in fact, produce
more viable phenotypic variation than do mutations. This is because mutations are not only rare,
but usually deleterious. In contrast, a single environmental factor may alter the phenotypes of an
entire population, providing natural selection with access to perhaps thousands of
environmentally altered individuals, as opposed to a single mutant individual. In addition,
mutations generally arise randomly with no correlation to specific environments, whereas new
environmentally induced phenotypes are both directional and highly correlated with the specific
new environment, allowing new environments to immediately produce and select among new
phenotypes.
Including phenotypic plasticity produces a better model: As suggested above, the inclusion of
phenotypic plasticity can result in a better model than mutation-allelic substitution alone in
explaining the production of organismal diversity. For example, the initial evolution of warning
color (aposematism), starting as a rare mutation is problematic because conspicuous prey should
be quickly found and removed by predators (Lindström et al. 2001). In contrast, evolution of
aposematism is easily explained by phenotypic plasticity (Sword 2002). Likewise, for
development, phenotypic plasticity explains the evolution of allometry and exaggerated
morphologies (Emlen and Nijhout 2000, Shingleton et al. 2007). For physiology, phenotypic
plasticity explains adaptive, beneficial plasticities such as acclimation and response to exercise
(Swallow et al. 2005), quite well. In ecology, it aids our un.
The Biological Control of Pests Research Unit (BCPRU) conducts research on developing biological and environmentally-friendly pest management methods. It works on mass production and delivery of beneficial organisms, as well as classical biocontrol of invasive pests. Current research includes rearing economically important insect species, identifying compounds for invasive ant control, and using pathogens to manage invasive plants. The BCPRU is working to improve mass production methods for predatory mites and ladybird beetles to control spider mites and aphids. It is also studying the social immunity of fire ants to identify better biological control agents, and developing methods to microencapsulate the fungus Trichoderma for controlling insect pests.
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Three studies investigated factors that affect the decline of honeybee populations. A 2011 Indian study found that electromagnetic radiation from mobile phones interfered with honeybees' navigational abilities and reduced queen egg-laying. A 2011 study showed that pesticide residues in brood comb delayed honeybee development and shortened lifespans. A 2014 study described gut parasites like Nosema apis and Nosema ceranae as increasing honeybee mortality, though the parasites' biology was poorly understood. While these studies highlighted various physical, chemical, and biological factors impacting honeybee populations, their conclusions had limitations due to imprecise discussions of mechanisms and physiological effects.
The Early Development of Gender DifferencesAuthor(s) M.docxAASTHA76
The Early Development of Gender Differences
Author(s): Matthew H. McIntyre and Carolyn Pope Edwards
Source: Annual Review of Anthropology, Vol. 38 (2009), pp. 83-97
Published by: Annual Reviews
Stable URL: https://www.jstor.org/stable/20622642
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The Early Development
of Gender Differences
Matthew H. Mclntyre1 and Carolyn Pope Edwards2
1 Department of Anthropology, University of Central Florida, Orlando, Florida 32816;
email: [email protected]
2 Departments of Psychology and Child, Youth, and Family Studies, University of Nebraska,
Lincoln, Nebraska 68588; email: [email protected]
Annu. Rev. Anthropol. 2009.38:83-97
First published online as a Review in Advance on
June 17,2009
The Annual Review of Anthropology is online at
anthro.annualreviews.org
This article's doi:
10.11467annurev-anthro-091908-1643 3 8
Copyright ? 2009 by Annual Reviews.
All rights reserved
0084-6570/09/1021-0083$20.00
Key Words
reproductive ecology, evolutionary psychology, patriarchy,
dominance, temperament
Abstract
This article reviews findings from anthropology, psychology, and other
disciplines about the role of biological factors in the development of
sex differences in human behavior, including biological theories, the
developmental course of sex differences, and the interaction of biologi
cal and cultural gendering processes at different ages. Current evidence
suggests that major biological influences on individual differences in
human gender, to the extent that they exist, operate primarily in early
development, during and especially prior to puberty. Biological effects
are likely to be mediated by relatively simple processes, like temper
ament, which are then elaborated through social interactions (as with
mother and peers) into more complex gendered features of adult person
ality. Biological anthropologists and psychologists interested in gender
should direct more attention to understanding how social processes in
fluence the development and function of the reproductive endocrine
system.
83
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INTRODUCTION
The purpose of this review is to summari.
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This study used stereo photography to collect quantitative 3D data on the structure and movement of large starling flocks during aerial displays over roosting sites. The researchers were able to reconstruct the positions of hundreds to thousands of individual starlings in cohesive flocks. Their analysis characterized global flock properties like shape, size, orientation and movement. They also investigated the internal flock structure, finding non-uniform density profiles with birds packed more tightly at the edges. This data provides an empirical benchmark for testing models of collective animal behavior and insights into flocking as an emergent property of group interactions.
The document summarizes a study that investigated how genetically variable germination timing in Arabidopsis thaliana influences the evolution of plant life histories. The researchers grew recombinant inbred lines of A. thaliana under different photoperiod and geographic conditions to manipulate germination timing. They found that adult life history traits exhibited strong plasticity depending on season of germination. The season of germination also significantly altered the strength, mode, and direction of natural selection on life history traits. However, the average plastic responses to season were not adaptive. Genetic variation in germination timing increased genetic variation in adult traits but did not increase heritability due to also increasing environmental variation. Under some conditions, plasticity in response to genetically variable germination
Macroevolution examines evolution over long time periods of thousands to millions of years. It studies changes above the species level, including the emergence of new species through speciation and loss of species through extinction. Key areas of study in macroevolution include building phylogenetic trees to demonstrate evolutionary relationships between extinct and modern species based on morphological comparisons, and using molecular analysis to help validate these relationships when possible. Mass extinctions that eliminate large percentages of species are also investigated to better understand causes and patterns of extinction and subsequent radiations as new species evolve to fill open niches.
This study examined the relationship between social dominance rank, stress levels, and reproductive success in female yellow-bellied marmots. The researchers found that high-ranking females had lower stress hormone levels and larger litters. However, females with the highest stress levels were more likely to successfully wean a litter. Body condition, as measured by previous year's mass, was also positively associated with breeding and weaning larger litters. Thus, while low-ranking females likely experienced more social stress, elevated stress levels did not seem to suppress reproduction in this species where females only have one chance to reproduce each year.
Simultaneous pollinator occurence (hymenoptera, agaoninae) in a threatened sp...Robert Mts
This study found evidence that two species of Pegoscapus wasps simultaneously pollinate Ficus mexiae, a threatened fig species in Brazil. The researchers analyzed 57 syconia from two F. mexiae trees and found that both Pegoscapus sp. 1 and Pegoscapus sp. 2 emerged from the syconia, with Pegoscapus sp. 2 being more abundant. While both wasp species were found to contribute to pollination and seed production, their relationship seems competitive, as their abundances were negatively correlated. This provides preliminary evidence that F. mexiae relies on both wasp species for pollination, and maintains diversity in Neotropical figs.
Similar to Social influeces on body size and devlopmental time in the bumblebee Bombus terrestris (20)
Simultaneous pollinator occurence (hymenoptera, agaoninae) in a threatened sp...
Social influeces on body size and devlopmental time in the bumblebee Bombus terrestris
1. 1 23
Behavioral Ecology and Sociobiology
ISSN 0340-5443
Behav Ecol Sociobiol
DOI 10.1007/s00265-013-1571-0
Social influences on body size and
developmental time in the bumblebee
Bombus terrestris
Hagai Shpigler, Matan Tamarkin, Yael
Gruber, Maayan Poleg, Adam J. Siegel &
Guy Bloch
2. 1 23
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3. ORIGINAL PAPER
Social influences on body size and developmental time
in the bumblebee Bombus terrestris
Hagai Shpigler & Matan Tamarkin & Yael Gruber &
Maayan Poleg & Adam J. Siegel & Guy Bloch
Received: 9 June 2013 /Accepted: 11 June 2013
# Springer-Verlag Berlin Heidelberg 2013
Abstract In many social insects, including bumblebees, the
division of labor between workers relates to body size, but
little is known about the factors influencing larval develop-
ment and final size. We confirmed and extend the evidence
that in the bumblebee Bombus terrestris the adult bee body
size is positively correlated with colony age. We next
performed cross-fostering experiments in which eggs were
switched between incipient (before worker emergence) and
later stage colonies with workers. The introduced eggs de-
veloped into adults similar in size to their unrelated
nestmates and not to their same-age full sisters developing
in their mother colony. Detailed observations revealed that
brood tending by the queen decreases, but does not cease, in
young colonies with workers. We next showed that both
worker number and the queen presence influenced the final
size of the developing brood, but only the queen influence
was mediated by shortening developmental time. In colonies
separated by a queen excluder, brood developmental time
was shorter in the queenright compartment. These findings
suggest that differences in body size are regulated by the
brood interactions with the queen and workers, and not by
factors inside the eggs that could vary along with colony
development. Finally, we developed a model showing that
the typical increase in worker number and the decrease in
brood contact with the queen can account for the typical
increase in body size. Similar self-organized social regula-
tion of brood development may contribute to the optimiza-
tion of growth and reproduction in additional social insects.
Keywords Bumblebee . Bombus terrestris . Size
determination . Division of labor . Caste determination .
Alloethism
Introduction
Division of labor among workers is one of the organization
principles of insect societies. Studies on the mechanisms that
influence task performance are therefore critical for under-
standing both the function and the evolution of insect soci-
eties. In many social insects, division of labor is based on
profound variation in worker body size, a system that is
termed “alloethism” (Wilson 1971). Alloethism is common
in social insects such as ants (Wilson 1978), bees (Goulson
et al. 2005), and termites (Miura and Matsumoto 1995).
Large workers typically specialize in activities outside the
nest such as foraging and nest defense whereas small
workers are more likely to perform activities inside the nest
including brood care and nest cleaning (Wilson 1971). By
contrast to the mechanisms of age-related division of labor
which have been extensively studied in honey bees (e.g.,
Robinson 1992; Beshers and Fewell 2001; Smith et al.
2008; Calderone and Page 1991; Seeley and Kolmes
1991), little is known about the mechanisms regulating
size-related division of labor.
Communicated by R. F. A. Moritz
Electronic supplementary material The online version of this article
(doi:10.1007/s00265-013-1571-0) contains supplementary material,
which is available to authorized users.
H. Shpigler (*) :M. Tamarkin :Y. Gruber :M. Poleg :
G. Bloch (*)
Department of Ecology, Evolution, and Behavior,
The Alexander Silberman Institute of Life Sciences,
The Hebrew University of Jerusalem, Jerusalem, Israel
e-mail: hagai.shpigler@mail.huji.ac.il
e-mail: bloch@vms.huji.ac.il
A. J. Siegel
The School of Life Sciences, Arizona State University,
Tempe, AZ, USA
Present Address:
A. J. Siegel
Department of Ecology, Evolution, and Behavior,
The Alexander Silberman Institute of Life Sciences,
The Hebrew University of Jerusalem, Jerusalem, Israel
Behav Ecol Sociobiol
DOI 10.1007/s00265-013-1571-0
Author's personal copy
4. Insect body size is influenced by internal and external
factors, and their interactions (Nijhout 2003; Davidowitz
et al. 2004). Internal factors influencing size polymorphism
include genetic variation between individuals, epigenetic
markers, and hormones or resources deposited in the egg.
For example, in the fruit fly Drosophila melanogaster genetic
dissections have linked specific genes and molecular path-
ways such as MAP4K3, Hippo, and the insulin/insulin-like
signaling pathway to the developmental processes determin-
ing adult body size (Edgar 2006; Pan 2007; Bryk et al. 2010).
Mutant fruit flies developing with no prothoracicotropic hor-
mone (PTTH) show prolonged larval growth and an increase
in ultimate adult mass (McBrayer et al. 2007). In honey bees,
specific areas in the genome (QTLs—quantitative trait loci)
are associated with body size differences between European
and African subspecies (Hunt et al. 1998). In the moth
Manduca sexta, lack of Juvenile Hormone (JH) in the last
larva instar resulted in early pupation and miniature adults
(Nijhout and Williams 1974); in the ant Pheidole bicarinata,
elevated JH levels during the last larval instar induced the
larvae to develop to soldier workers that are significantly
larger than typical workers (Wheeler and Nijhout 1981). In
some harvester (Genus Pogonomyrmex) and Pheidole
pallidula ants, ecdysteroids deposited in the egg by the queen
influence the development and ultimate body size, as well as
the caste of the larvae (Suzzoni et al. 1980; Schwander et al.
2008). In the termite Reticulitermes speratus, the queen ad-
justs the egg size according to colony development (Matsuura
and Kobayashi 2010).
Many external factors also influence insect body size. For
example, the ambient temperature was shown to influence
the development of several species including M. sexta
(Davidowitz et al. 2003, 2004) and the solitary bee Osmia
bicornis (Radmacher and Strohm 2010). Food amount and
composition can also have major impacts on insect body size
(Davidowitz et al. 2004; Sutcliffe and Plowright 1990;
Roulston and Cane 2000, 2002; Tasei and Aupinel 2008;
Radmacher and Strohm 2010; Quezada-Euan et al. 2011).
The diet fed to female larvae determines caste in honey bees
(Patel et al. 2007; Smith et al. 2008).
The goal of our study was to identify factors that influence
body size in the bumblebee Bombus terrestris. Bumblebees
(tribe Bombini) are an important and large taxon of social
insects showing size-related division of labor. Bumblebees are
commonly considered “primitively eusocial” since there are
no morphological differences between queens and workers
other than size (Michener 1974; Cnaani and Hefetz 2001;
Goulson 2003), and there is less specialization in the division
of labor relative to highly eusocial species such as honey bees
and ants (Michener 1974; Goulson 2003; Jandt et al. 2009). In
temperate regions, bumblebee colonies are typically founded
during the spring by a single mated overwintered queen and
reach a population of up to few hundred workers. The worker
population shows profound size polymorphism with up to
tenfold difference in body mass (Michener 1974; Alford
1975). Worker body size is associated with task performance.
Smaller bees typically perform more in-nest activities such as
brood care, whereas larger bees are more likely to forage
outside the nest (Cumber 1949; Brian 1952; Free 1955;
Michener 1974; Alford 1975; Yerushalmi et al. 2006).
Larger bees are more efficient in bringing pollen and nectar
back to the colony (Goulson et al. 2002; Spaethe and
Weidenmuller 2002). They appear to be better suited for
forging activities as they have better visual discrimination,
odor sensitivity, learning abilities, and stronger circadian
rhythms and phototactic response compared with their smaller
full-sister bees (Spaethe and Chittka 2003; Worden et al. 2005;
Yerushalmi et al. 2006; Kapustjanskij et al. 2007; Spaethe
et al. 2007; Merling 2008). These differences in behavior are
associated with relevant size-related variation in morphology
and neuroanatomy. Larger workers have more ommatidia with
wider facets in their compound eyes, elevated density of
olfactory sensilla on the antennae, and additional brain neu-
rons that are immunostained with antiserum against the circa-
dian neuropeptide Pigment Dispersing Factor (PDF) com-
pared with their smaller sisters (Spaethe and Chittka 2003;
Spaethe et al. 2007; Weiss et al. 2009). Additionally, variation
in metabolic and stress response protein levels in the brain and
abdomen between small and large sister workers has been
recently reported (Wolschin et al. 2012).
We hypothesized that both internal factors in the eggs, such
as hormones or nutritional factors, and environmental factors,
such as the number of workers in the colony and the presence
or absence of the queen, may influence larval development and
adult body size. Previous studies suggest that genetic variation
does not account for the profound size polymorphism in bum-
blebees. Full-sister workers, which are very similar genetically,
still differ profoundly in body size (Schmid-Hempel and
Schmid-Hempel 2000); sib-mating, which further reduces ge-
netic variation, does not influence the variation in body size of
workers or drones (Gerloff et al. 2003).
We first recorded the body size of bumblebee workers
emerging from colonies in the laboratory. This experiment
was performed to confirm and expand on earlier results
demonstrating that worker body size increases with colony
age. We next performed a cross-fostering experiment
allowing us to decouple the influence of factors in the eggs
from environmental determinants of body size. Given the
support to the hypothesis that the bee ultimate body size is
under strong environmental influence, we then performed
additional experiments to explore the influence of specific
social factors including queen presence and worker number.
We then conducted detailed observations of queen behavior
relating to larval care to further elucidate her maternal care
role and the specific effects of queen–brood interactions.
Lastly, we used a split-colony design by queen excluder to
Behav Ecol Sociobiol
Author's personal copy
5. demonstrate that the queen influence is at least partially
mediated by close distance interactions with the larvae.
Materials and methods
Bumblebees
B. terrestris founding queens and incipient colonies were
obtained from Polyam Pollination Services, Kibbutz Yad-
Mordechai, Israel. Incipient colonies contained a queen, 5–
10 workers, and brood in various developmental stages.
Founding queens were obtained after diapause and before
they started to lay eggs. Each colony or founding queen was
housed in a wooden nesting box (21×21×12 cm). The nesting
boxes included a front wall and a top cover made of transpar-
ent Plexiglas®, enabling detailed observations of colony de-
velopment, comb structure, and bee behavior. The nesting
boxes were placed in an environmental chamber [29±1 °C;
45±5 % relative humidity (RH)] in constant darkness at the
Bee Research Facility at the Edmond J. Safra campus of the
Hebrew University of Jerusalem. The experiments were
conducted between January 2010 and July 2011. The colonies
were fed ad libitum with commercial sugar syrup obtained
from Polyam Pollination Services and “pollen cakes” made of
fresh pollen (collected by honey bees) mixed with sugar
syrup. All observations and treatments were made under dim
red light. As an index for body size, we measured (under a
dissection microscope, ×10 magnification) the length of the
front wing marginal cell. The length of the marginal cell is
highly correlated with wing length and other indices for body
size, can be precisely measured, and does not change with age
or flight intensity (Knee and Medler 1965; Owen 1988;
Yerushalmi et al. 2006).
Experiment 1: the influence of colony stage on the body size
of emerging bees
The aim of this experiment was to record the body size of bees
emerging in typical colonies in the laboratory. We housed two
incipient bumblebee colonies in nesting boxes as described
above. We collected all newly emerging bees (0–48 h post-
emergence) during the first 50 days following the emergence of
the first worker and tagged each bee with a colored number tag
(Graze, Weinstadt, Germany). After 50 days, we froze the
colony (−20 °C) and measured the length of the marginal wing
cell for all tagged bees. Given that in B. terrestris there is no
overlap between the body size of queens and workers (Goulson
2003; see also Cnaani and Hefetz 2001), we assumed that
significantly larger (marginal cell >4.2 mm) female bees emerg-
ing at the latest stages of colony development are queens (in
this study, marginal cell size range for workers was 2.05–
3.6 mm, n=713, and for queens 4.2–4.8 mm, n=51). We
analyzed the results using a linear regression model, with day
of emergence as the independent variable and the length of the
marginal cell as the dependent variable (SPSS 17.0 software
package, IBM, was used for all statistical analysis in this study).
Experiment 2: the influence of internal factors in the egg
and colony stage on worker body size
We used a cross-fostering experimental design in which we
switched batches of eggs between founding colonies
(“Incipient”) and young colonies at a more advanced stage of
development (“Established”). The incipient colonies contained
only the mother queen and her first batches of eggs. The
established colonies were 5–8 days after the emergence of
the first worker and contained a queen, 5–10 workers, and
brood at all stages of development. To transfer eggs between
colonies, we first removed all bees from both the incipient and
the established colonies. We then collected 6–10 eggs from
each colony and transplanted them into an empty egg cup in
the paired colony of the alternate maturity from which we had
already removed the local eggs. Transferred eggs were 2–
3 days old. We used a standard beekeeping grafting tool to
collect and transfer the eggs between the colonies. After plac-
ing the eggs gently inside the recipient egg cup of the host
colony, we carefully sealed the cup with wax from the host
colony (as in Bloch 1999). Following cup sealing, we first
returned the queen and shortly afterwards the workers back to
the nest box. In each colony, we also had sham handled egg
cups of a similar age that were similarly opened and sealed, but
without removing the eggs. The sham treatment served as a
control for the interference associated with opening and
resealing the egg cups. The whole procedure lasted ∼15 min.
We observed the colony for 3 h following the manipulation to
assure that the queen did not replace the introduced eggs with
her own eggs. To track the position and development of the
cross-fostered and control brood, we photographed the wax
comb every 1–2 days. When the focal larvae had pupated, we
transferred them into a small box (8×12×5 cm) in which they
emerged. We then froze the bees emerging from these pupae
and measured their size as described above. We used a one-
way ANOVA followed by Fisher’s least significant difference
(LSD) post hoc test to analyze the results. We repeated this
experiment three times (using new colonies for each replicate).
Experiment 3: the contribution of the queen and the workers
to larval nursing during early stages of colony development
In order to quantify brood nursing by the queen and workers,
we preformed detailed observations in which we recorded
larvae feeding in colonies at early stages of development. We
observed incipient colonies with the founding queen and her
first batch of eggs. A second set of observations was performed
after the second batch of eggs was laid in these colonies, which
Behav Ecol Sociobiol
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6. at this point contained at least 10 workers. The second set of
observations was performed 23–27 days after the first batch of
eggs was laid. In each set of observations, we observed the
focal brood cells for 1 h each day for five successive days.
During each observation, we recorded all feeding events by the
queen and the workers. A feeding event was recorded when a
bee was seen opening a larval cup, inserting her head into the
cup, and contracting her abdomen (Ribeiro 1999). The age of
the larvae was recorded relative to the clearly identified day of
pupation. This experiment was repeated with four different
colonies. We used Student’s t test to compare the average total
number of feeding events between the two colony stages for the
four replicates. The number of focal larvae fed during the
observation session was estimated based on counting the num-
ber of adult bees developing from the focal larvae cups. In
addition, at each observation day we counted the number of
larvae in individual cells. During the early stages of develop-
ment, bumblebee larvae are clumped together in a common
cell, but later at about 5 days before pupation each larva has its
own individual wax cover and can be clearly identified. The
number of emerging adults was very similar to the number of
counted larvae suggesting that there was no significant mortal-
ity between the larva and adult stages. The colonies were
healthy, developed normally, and there were no indication for
significant larval death in our focal groups during the last 5 days
prior to pupation when most of our data was collected. Finally,
we analyzed the results of each batch separately using a linear
regression model, with age of the larvae as the independent
variable and the average number of feeding as dependent
variable. We used Wilcoxon signed rank test to compare feed-
ing rate in the first and second batch for each of the colonies.
Experiment 4: the influences of queen presence and worker
number on brood developmental time and final body size
In this experiment, we compared the offspring of a single
queen developing in four different social environments
(treatments): (1) 10 workers without a queen (10w), (2) a
single worker (w), (3) a single queen (Q), and (4) a queen
with 10 or more workers (Q, 10+w) (see Supplementary
Fig. 1 for flow chart for this experiment). We placed a young
colony founding queen together with 12 foreign (not her
offspring) 1-day-old workers in a small wooden cage
(8×12×5 cm) and left her for 2–3 days to lay her first batch
of eggs. We then transferred the queen together with two
workers into a new cage, leaving the eggs to develop with
the remaining 10 workers (10w, treatment 1). We left the
queen and the two workers for 1–3 days in the new cage to
lay a second batch of eggs, and then removed the queen
together with one of the workers and placed them in a new
cage; the eggs of the second batch were left to develop with
the remaining single worker (1w, treatment 2). After 1–2 days
when the queen laid in the new cage, we removed the worker
and left the queen to rear her brood by herself (Q, treatment 3;
a treatment that most closely resembles a natural colony at the
founding stage). We color marked all the workers that devel-
oped from the brood of treatment 3. When 10 workers were
present, we moved the entire colony into a larger nesting box
(21×21×20 cm). The queen laid additional eggs in the new
nesting box within 1 day. We tracked this batch of eggs, which
were tended by the full-sister workers and by the queen (Q,
10+w, treatment 4). The queens calmed down quite rapidly
after each transferred and laid again; at the day following
transfer, they seemed to behave normally. We followed the
development of all four brood batches and recorded the days
in which they emerged as adults. When all adult bees had
emerged from the focal batches, we froze them and later
measured their size as described above. All the cages with
the brood experiencing the four different treatments were
housed in the same environmental chamber (29±1 °C;
45±5 % RH). We repeated the experiment simultaneously
with three queens. We used a one-way ANOVA with LSD
post hoc tests to compare body size and development duration
for bees that developed in the four social environments (a flow
chart for the experiment is provided in Supplementary Fig. 1).
Experiment 5: the influence of close distance interactions
with the queen on brood size and developmental time
We compared two brood batches from the same colony sepa-
rated by a queen excluder mesh (workers, but not the queen,
were able to pass through the mesh). We split a young colony
(3–7 days after first worker emergence) that was housed in a
nesting box (21×21×20 cm) into two parts using a queen
excluder mesh (8×8-mm holes; herein referred to as “queen
excluder colonies”). There were egg cells with known day of
oviposition on both sides of the queen excluder. To motivate the
workers to move across the queen excluder, we placed the
1.0
1.5
2.0
2.5
3.0
3.5
4.0
4.5
0 5 10 15 20 25 30 35 40 45 50
Colony age (days after first worker emergence)
Marginalcelllength(mm)
Fig. 1 The body size of newly emerging bees is positively correlated
with colony age. Each filled diamond represents a single worker bee
(n=101); each open circle represents a gyne (n=4). Day 1 is the day of
first worker emergence. There is a significant positive correlation be-
tween worker body size and colony age (linear regression R2
=0.59,
p<0.001). A similar analysis for an additional colony is presented in
Supplementary Fig. 3
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7. pollen on the queenright side and the sugar syrup on the
queenless side of the colony. We tracked the development of
the brood on both sides of the mesh by daily photographing the
nest. When the focal larvae had pupated, we transferred them
into a small box (8×12×5 cm) in which they emerged. We then
froze the bees emerging from these pupae and measured their
size as described above. In control queenright colonies, we
conducted the same procedure but used a mesh allowing a free
queen passage (10×10-mm holes + 2 holes of 20×20 mm;
herein referred to as “queenright colonies”). A second control
colony was as described above but without a queen in the nest.
The separating mesh allowed free worker passage (10×10 mm;
herein referred to as “queenless colonies”). We repeated this
experiment three times. We used Student’s t tests to compare
the body size and developmental time between the two sides of
each colony and nested ANOVAwith Scheffe’s post hoc tests to
compare between the different colony types.
Results
Experiment 1: the influence of colony stage on the body size
of emerging bees
Bee body size was positively correlated with colony stage,
measured as days after the emergence of the first worker
(Fig. 1; R2
=0.59, p<0.001). The workers that emerged during
early stages of colony development were smaller compared
with their later emerging full sisters. The average length of the
front wing marginal cell in the first brood was 2.34±0.13 mm
(n=7) compared with 3.15±0.05 mm (n=10) in the last batch
of workers emerging just before the emergence of the first
gynes (virgin queens; two-tailed Student’s t test, p<0.001;
similar size differences for bees from additional four colonies
from experiment 3 are summarized in Supplementary Fig. 2).
In a second colony that we monitored, both males and females
began emerging at the onset of colony development. This
pattern is atypical as haploid males normally only emerge
during the later stages of colony development (Alford 1975;
Goulson 2003). Early emergence of males as observed in this
colony typically indicates that males are developing from
diploid eggs that are produced when a queen mates with a
male with a similar allele to hers at the sex determination locus
(Duchateau et al. 1994). Nevertheless, this colony also showed
a similar positive correlation between worker body size and
colony age. The slope of the regression line for the males was
similar to that of the workers, though males were significantly
larger at all stages (males = 3.24±0.05 mm, n=46; workers =
2.84±0.04 mm, n=56; two-tailed Student’s t test, p<0.001;
Supplementary Fig. 3). This study presents the most detailed
correlation between body size and colony age in bumblebees.
The results confirm and extend previous studies with bumble-
bees (Knee and Medler 1965; Plowright and Jay 1968).
Experiment 2: the influence of internal factors in the egg
and colony stage on worker body size
The increase in body size with colony development in the first
experiment could stem from differences in the eggs laid by the
queen at different colony stages (e.g., genotype, epigenetic
markers, or hormonal differences), from changes in the colony
environment (e.g., worker or brood number), or from both. To
uncouple these two sources of variation, we used a cross-
fostering experimental design in which we exchanged eggs
between an incipient colony (queen and her first batch of
eggs) and an established colony (a queen with ∼10 workers
and brood in all stages of development). In all three trials of
this experiment, the introduced eggs developed into bees with
a body size similar to that of nestmates developing in the
foster colony at the same time (Fig. 2, one-way ANOVA,
p<0.001). The body size of bees emerging from introduced
eggs was significantly different from that of their full sisters
Incipient Established
Trial 1
0
1
2
3 b
4
b
21
a
9
a
6
Trial 2
0
1
2
3
Marginalcelllength(mm)
a
6
a
7
b
7
b
13
0
1
2
3
a
4
a
6
Local
b
6
Incipient
b
5
EstablishedLocalSource:
Host:
Trial 3
Fig. 2 The colony environment rather than factors in the eggs influences
the increase in body size with colony development. We used a cross-
fostering experimental design, switching eggs between a colony with only
a queen (Incipient) and a colony at a later stage containing a queen, 10
workers, and brood in all stages (Established). Egg cells of similar age in
the host colony (Local) served as the control. Source indicates the source
colony in which the eggs were laid and Host indicates the foster colony in
which the brood emerging from these eggs developed. The Local egg cups
were sham handled. Values are mean±SE; sample size is given inside the
bars. Body size of emerging brood differed between treatment groups in
all three repetitions (one-way ANOVA, p<0.001); bars with different
letters are significantly different (LSD post hoc test, p<0.05). Bars with
the same filled color in each trial indicate that the bees were full sisters
Behav Ecol Sociobiol
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8. who remained in the source (donor) colony (Fig. 2). In all
three trials, the bees (local or introduced) that developed in an
incipient colony were smaller than those from an established
colony (local or introduced). These results indicate that the
nest environment rather than internal factors in the egg de-
termines the final body size of the developing brood.
Experiment 3: the contribution of the queen and the workers
to larva nursing during early stages of colony development
To study brood care during colony development, we ob-
served the number of feeding events per larva in colonies
containing the first or second brood batches. During the
founding stage, only the queen cared for the brood whereas
in colonies with a second batch of brood, both the queen and
the workers cared for the brood. Our observations indicated
that the queen continued to feed the larvae of the second
batch mostly at the early stages of brood development (7–
5 days before pupation). The percentage of feeding events by
the queen was about 7 % during the first 3 days of the
observations and later decreased to 0 % during the two last
observation days (Fig. 3). In all four trials, the bees emerging
from the second batch were significantly larger than bees
emerging from the first batch (Student’s t test, p<0.01;
Supplementary Fig. 2). In both batches, larvae growth was
associated with a progressive increase in the number of
feeding events per hour (Fig. 3; first batch—linear regression
model R2
=0.7, p=0.075; second batch—R2
=0.84, p=0.01).
The total number of larval feeding events per hour through-
out the entire observation period was similar for the first and
second batches (Wilcoxon signed rank test—p=0.222, n=4
colonies, 4 days). Our sample size was too small to compare
larvae at specific ages developing during the early and later
stages of colony development; we therefore cannot exclude
the possibility that the rate of feeding of larvae at certain ages
differs between the first and second batches. These observa-
tions show that the second batch of brood is fed mostly by
the workers, but the queen still tends the brood and feeds
larvae, primarily at early stages of development.
Experiment 4: the influence of queen presence and the number
of workers on brood developmental time and final body size
Given that our observations (Fig. 3) suggest that the frequen-
cy of brood contact with the queen and workers changes
during colony development, we next tested the influence of
the queen and the workers on larval developmental time and
ultimate body size in a tightly controlled laboratory setup.
Bees that developed in different social environments (“treat-
ments”, Supplementary Fig. 1) differed both in body size and
in development duration in all three trials of this experiment
(Fig. 4; one-way ANOVA, p<0.001). Bees that were cared
for by 10 workers without a queen were significantly larger
than bees cared for by 10 workers (or more) with a queen
(LSD post hoc test, p<0.05); some of these larvae developed
into gynes (trial 1—0/16, trial 2—1/5, trial 3—7/16). In trials
1 and 3, the brood raised by a queen with 10+ workers were
significantly larger than those reared by a queen alone (LSD
post hoc test, p<0.05), a similar but statistically insignificant
trend was seen in trial 2 (p=0.075). There was no consistent
trend across trials for the comparison of body size for brood
reared by a single queen or a single worker. In all three trials,
the duration of development from egg to adult was shorter
when a queen was present compared to queenless conditions
(Fig. 4; one-way ANOVA, p<0.001; LSD post hoc test,
p<0.05). Developmental time was similar for brood in cages
with only a queen or with a queen and 10+ workers (LSD
post hoc test, p>0.05). The duration was also similar for
brood in cages with a single worker or 10+ workers in trials 1
and 2 (LSD post hoc test, p>0.05), and was longer for brood
attended by a single worker in trial 3 (LSD post hoc test,
p<0.05). These results suggests that both the presence of the
queen and the total number of nursing bees affect body size,
but of the factors tested, only the presence of the queen
affected brood developmental time.
Experiment 5: the influence of close distance interactions
with the queen on brood size and developmental time
Given our findings on the impact of the queen on brood
developmental time and body size in experiment 4, and our
observations of brood nursing in experiment 3, we tested
whether the queen influence is mediated through close dis-
tance interactions with the larvae. Bees developing in the
queenless side of the queen excluder in the “queen excluder
colonies”, and that did not have close distance interactions
15 16 17 18 19-13 -12 -11 -10…. 0 ….
Colony age (days relative to first worker emergence)
-5 -4 -3 -2
Numberoffeedingevents
/larva/hour
0
0.5
1
1.5
2
2.5
-7 -6 -5 -4 -3
Days before pupation
First batch Second batch
Fed by the queen Fed by the workers
Fig. 3 The queen continues to feed larvae in established colonies with
nurse workers. The first batch of brood is the brood from which the first
workers in the colony emerged. The second batch was laid when the
colony contained a queen and about 10 workers. The numbers below
the bars show the age of the larvae relative to the date of pupation
(0=day of pupation); the lower x-axis shows the age of the colony
relative to the emergence of the first worker (marked with a 0). Data is
based on direct observations of brood-tending behavior. Values are
mean±SE based on data from four different colonies
Behav Ecol Sociobiol
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9. with the queen, developed for an additional 2–3 days com-
pared with their sisters developing on the queenright side of
the colony (Student’s t test, p<0.001); the results were sim-
ilar across the three trails of this experiment. The size of the
bees from the two sides was similar in two repetitions and
was larger in the queenless side for the third repetition
(Student’s t test, p=0.02); none of the bees in these colonies
developed into gynes (Supplementary Fig. 4). In the
queenright colonies, the developmental time and the size of
the bees was the same on both sides of the mesh in all three
trials (Supplementary Fig. 4). In the queenless control colo-
nies, the size of the bees was the same on the two sides of the
mesh in all three trials; the developmental time was similar in
two colonies and longer in the pollen side in one colony
(Student’s t test, p<0.01). Most of the bees (39 out of 59) in
the queenless colonies developed into gynes. When compar-
ing the bees from the different treatments, we found that the
average size of the bees from the queenright colonies, the
queenright side of the queen excluder colonies, and the
queenless side of the queen excluder colonies was the same
and significantly smaller from the bees developing in the
queenless colonies (nested ANOVA, p<0.001; Fig. 5, lower
panel). Developmental time was similar for bees developing
in the queenright colonies, and in the queenright side of the
queen excluder colonies, and was significantly shorter than
for bees developing on the queenless side of the queen
excluder colonies and in the queenless colonies. The devel-
opmental time of the brood in the queenless side of the queen
excluder colonies was shorter compared with bees develop-
ing in the queenless colonies (nested ANOVA, p<0.001;
Fig. 5, upper panel). This experiment suggests that the queen
influences brood developmental time, ultimate body
size, and caste differentiation. Close distance interaction
(probably direct contact) with the queen influenced larval
developmental time.
Discussion
Size polymorphism is a hallmark of the division of labor in
many social insects, including bumblebees, but little is
known about the factors determining the body size of social
insects. Our results show that the typical increase in the body
size of emerging B. terrestris workers along with colony
development is influenced by changes in colony environ-
ment over time rather than by differences in the eggs laid by
the queen during different stages of colony growth. The
presence of a queen and the number of workers caring for
the brood influenced ultimate body size. The influence of the
queen was mediated by shortening larval developmental
duration, an effect that at least in part required close distance
interactions (probably direct contact) between the queen and
the larvae. To the best of our knowledge, this is the first
evidence that the queen influence on larval development in
bees is mediated by close distance interactions. These social
influences on brood development can in turn influence
Marginalcelllength(mm)
Developmentaltime(days)
1
2
3
4
5
a
6
b
5
b
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b
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aa
5 6
b
6
b
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25
30
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1
2
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16
a
9
b
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d
8
c
0
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30 aa
16 9
b
8
b
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b
a
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c
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c
23
0
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25
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10W 1W Q+ 10W1Q
0
1
2
3
4
16
a
5 23
b
16
c
b
10W 1W Q+ 10W1Q
Social environment
Body size Developmental time
Fig. 4 The presence of the queen and the number of workers affect
final body size and brood developmental time. Left column: worker
body size; right column: egg to adult developmental time. 10W: 10
workers without a queen, 1W: a single worker, 1Q: a single egg-laying
queen, Q+≥10W: an egg-laying queen with 10 or more workers and
brood in all stages. Each row depicts a different repetition of the
experiment. Values are mean±SE; sample size is given inside the bars.
Body size of emerging brood and developmental time differed between
treatment groups in all three repetitions (one-way ANOVA, p<0.001);
groups with different letters are significantly different (LSD post hoc
test, p<0.05). The same queen laid all of the eggs for the four experi-
mental groups in each trial
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10. worker division of labor and the social organization of the
whole colony.
The positive correlation between body size and colony
age was very consistent in our experiments, and corresponds
with previous measurements in field and laboratory colonies
(Knee and Medler 1965; Plowright and Jay 1968; Goulson
2003). However, it was important to precisely quantify bee
body size over the entire period of worker production as a
similar increase was not found in all studies (Duchateau
1989; Couvillon et al. 2010). It is not clear whether this
apparent inconsistency stems from species-specific varia-
tion, differences in data collection (e.g., in some of the
studies size was measured only for bees emerging during
the later stages of colony development), or resulted from
stress associated with manipulating colonies in some of these
studies. For example, Knee and Medler (1965) showed that
colonies that were transferred from the field to the laboratory
or were infected with parasites reared small workers and did
not show the typical increase in average body size with
colony development.
The cross-fostering experiment (experiment 2, Fig. 2)
showed that the typical increase in body size can be
explained by variation in the colony environment, but not
by differences between the eggs laid by the queen at early
versus later stages of colony development. All the colonies in
the cross fostering experiment were housed in the same
environmental chamber and therefore experienced similar
temperature, humidity, and illumination, and were provided
with the same food ad libitum. Therefore, it is likely that
social rather than physical factors differing between the
incipient and established colonies accounted for the ob-
served influence of the environments on worker body size.
We focused on two key social factors, the number of workers
present and larval interactions with the queen. Both appear to
be important. Notably, however, the queen and worker in-
fluences on larval growth appear to be mediated by different
mechanisms since only the queen presence reduced brood
developmental duration. We found that brood reared by 10
workers with or without a queen were larger than sister brood
cared for by a single worker or a queen (Fig. 4). These results
are consistent with the premise that the number of workers or
the worker/larva ratio influence brood development and ul-
timate body size in bumblebees (Plowright and Jay 1968).
However, the body size of the nursing workers does not seem
to be an important factor as brood nursed by large or small
worker bees in colonies at the same developmental stage
developed into adult workers of a similar size (Cnaani and
Hefetz 1994).
The importance of interactions with the queen for brood
development and final size was evident in experiment 4 in
which larger bees developed when reared by 10 workers
without a queen compared to 10 or more workers with a
queen (Fig. 4). The adult/larva ratio in these two groups
appeared similar (but this was not precisely quantified),
and we therefore assume that the presence of the queen was
the most important factor varying between these treatment
groups. The presence of a queen also inhibits the develop-
ment of female larvae into new queens, which are not only
larger than workers but also differ in their physiology
(Cnaani et al. 2000a, b). Experiment 5 further showed that
the influence of the queen on larvae development is mediated
at least in part by close distance interactions, probably direct
contact. The developmental time (and in one colony also
body size) differed between the queenless and queenright
sides of the excluder in the queen excluder colonies. In a
broader evolutionary perspective, the finding that the queen
inhibits larval growth is consistent with predictions of the
Parental Manipulation Hypothesis for the evolution of euso-
ciality (Alexander 1974).
85 60 84 59
0
5
10
15
20
25
30
35
40
45
QR
colony
QR side QL side QL
colony
Margingalcelllenght(mm)
a
a a
b
QE colony
Treatment
85 60 84 59
0
5
10
15
20
25
30
35
Developmentaltime(days) a a
b
c
Fig. 5 The queen influences on larval developmental time and ultimate
body size are mediated by both long and close distance signals. Colo-
nies were split into two equal parts using a queen excluder (QE colony);
larval developmental time and size for the queenright side (QR side) and
the queenless side (QL side) were tracked. Control queenright colonies
(QR colonies) were separated by mesh enabling the queen to visit all
parts of the nest. Control queenless colonies (QL colony) had a mesh
allowing the worker to pass between sides but did not have a queen. The
data presented in the plots were pooled from three independent repeti-
tions. Detailed data for each repetition is presented in Supplementary
Fig. 3. Values are mean±SE; sample size is given inside the bars. Both
body size (lower panel) and developmental time (upper panel) differed
between treatments (nested ANOVA, p<0.001). Treatments with dif-
ferent letters were significantly different (Scheffe post hoc test, p<0.05)
Behav Ecol Sociobiol
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11. Our findings suggest that there is a “critical period” dur-
ing larval growth in which it is most sensitive to inhibitory
signals from the queen. Critical periods during early devel-
opmental stages with profound influence on later develop-
mental programs have been described in many animal spe-
cies (Smith et al. 2008; Schwander et al. 2010). In B.
terrestris, it has been shown that the first 5 days during larval
development are the critical period for caste determination
(Cnaani et al. 2000b) and may also be critical for the devel-
opmental program determining body size. Additional factors
that we did not test such as the amount or quality of food
provided to the larvae may also influence larval growth and
final body size. Differences in diet, including in the amount
of Major Royal Jelly proteins, are important regulators of
honey bee development (e.g., Kamakura 2011). However,
their importance in bumblebees has been questioned because
no differences were found in the composition of the food
provided by the workers to gyne and worker destined larvae
(Pereboom 2000), and the single B. terrestris member of the
Major Royal Jelly protein family does not appear to have a
nutritive function (Kupke et al. 2012). Although we did not
find significant differences in feeding rates between incipient
and later stage colony, we do not argue that the amount of
food provided to the larvae does not change during colony
development. Ribeiro et al. (1999) reported, based on de-
tailed video recording and an extended observation period,
that larval feeding rate was significantly higher in colonies
with workers and a queen relative to colonies with only the
founding queen. In addition, differences in feeding frequen-
cy have been shown to affect the size and the weight of hand-
reared larvae (Pereboom et al. 2003). Perhaps, we did not
detect a statistically significant increase in the amount of
feeding events per larva in later stage colonies because we
observed the colonies for a relatively short period and in
colonies with a small number of workers (Fig. 3).
Our results show that the queen can also influence devel-
opment without close distance interactions with the brood;
gynes were developing in the queenless colonies but not in the
queenless part of the colony in the queen excluder colonies
(experiment 5). These findings suggest that in the later colo-
nies the queen influenced the development of brood also in the
side of the queen excluder that she could not reach. Röseler
(1970) similarly showed that larvae separated from the queen
by a queen excluder did not develop into gynes. The differ-
ences between the queenless colonies and the queenless side
of the queen excluder colonies in experiment 5 (Fig. 5) could
be mediated by volatile pheromones or by contact phero-
mones passing from the queen to the workers and to the larva
developing in the queenless compartment. It is also possible
that the queen influenced the behavior of workers with which
she interacted in the queenright side of the colony and who
cared for the brood in the queenless side of the colony. Lopez-
Vaamonde et al. (2007) split B. terrestris colonies with a
single or double mesh that did not allow queen or worker
passage and reported that under these conditions, the queen
did not inhibit queen production on the queenless compart-
ment. Transferring workers or wax once a day from the
queenright to the queenless compartment did not improve
the inhibition of gyne production in the queenless side. The
findings of Lopez-Vaamonde et al. (2007) are not consistent
with the hypotheses that volatile queen pheromones, contact
queen pheromones transferred by the worker, or queen-
induced changes in workers’ behavior mediate the inhibitory
influence of the queen on gyne production. Alaux et al. (2004)
showed that the queen inhibits workers’ reproduction in col-
onies split by a queen excluder, but only if the workers were in
continuous close exposure to the queen; the inhibition was
weaker compared to queenright workers. Thus, perhaps the
queen influence is mediated by altering workers’ behavior,
and this affect requires repeated exposure to the queen
that was not available in the worker transfer experiment
of Lopez-Vaamonde et al. (2007).
Brood contact with the queen decreases during the typical
development of the annual bumblebee colony. Our detailed
observations (Fig. 3) revealed that the queen continued to
feed larvae in the presence of workers, but at a reduced rate
compared with incipient colonies in which the queen is the
sole brood tender. These observations that focused on the
brood are consistent with complementary observations fo-
cusing on the queen and showing that in the presence of
workers (emerged naturally or supplemented experimental-
ly), the queen decreases her brood feeding activity compared
to when caring for the brood alone (in un-manipulated in-
cipient colonies or in young colonies from which all workers
were removed; Woodard et al. 2013).
Based on our studies and the literature, we propose a self-
organization model to explain how the natural increase in
worker number and variation in brood contact with the queen
may produce a gradual increase in worker body size along
with colony development (Fig. 6). The first batch of larvae in
the colony (leftmost part of the plot in Fig. 6) develops into
small bees because they are cared for by a single brood
tender (the queen), which is suboptimal (e.g., compare single
and multiple brood tender in Fig. 4), and because direct
contact with the queen appears to decrease larval develop-
mental duration (experiments 4 and 5). When workers
emerge, they contribute to brood nursing, and the increase
in their number may improve the overall care for brood, an
improvement that is reflected in larger final body size. The
influence of worker number on brood size was exemplified
by the consistent larger size of bees reared by 10 queenless
workers compared to a single worker in experiment 4 (Fig. 4,
left column). Pereboom et al. (2003) hand-reared larvae and
showed that larvae that are fed at higher rates attain larger
final size, and an increase in feeding rate in later stage
colonies was reported by Ribeiro et al. (1999).
Behav Ecol Sociobiol
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12. The emergence of the first workers in the colony is associ-
ated with a sharp decrease in the queen brood feeding rate
(Woodard et al. 2013), and her relative contribution to brood
care diminishes (Fig. 3). These two processes together lead to
a decrease in brood contact with the queen and enable the
development of larger brood. The combined effects of worker
number and queen contact can explain why in experiment 5
there was a consistent reduction in developmental time but not
in body size in the queenright side of the queen excluder
colonies; the large number of workers in these colonies could
provide more care and compensate for the inhibitory influence
of the queen. This premise is also consistent with the findings
of experiment 4 in which bees developing with a queen and 10
or more workers were larger than their sisters developing with
only a queen, but developmental time was similar for the two
groups (Fig. 4). Although our experiments were not designed
to explicitly test the social influence on caste determination,
our model suggests that the decrease in queen influence on
larva development and the increase in worker number may
culminate in large brood that develop into new gynes.
Consistent with this premise are the findings that an artificial
increase in worker number enhances new queen production
(Pomeroy and Plowright 1982; Bloch 1999).
Our study focused on factors affecting the increase in
worker body size during colony growth. However, it should
be noted that there is also significant size variation between
brood developing at the same colony stage (e.g., Fig. 1 and
Supplementary Fig. 3) and even between larvae developing
together in the same cell. In several species, including Bombus
impatiens, there is evidence suggesting that some of this
variation can be explained by the brood location. It has been
suggested that brood developing in the periphery of the comb
are “neglected”, receiving less food, and are therefore smaller
than brood located at the center of the comb (Plowright and
Jay 1968; Couvillon and Dornhaus 2009). It would be inter-
esting to test whether brood location affects the contact with
the queen and the feeding by the workers, or if this variation is
generated by factors that are not included in our model.
An increase in worker size along with colony development
has also been reported in several other social insects including
paper wasps (Jeanne and Suryanarayanan 2011; Miyano 1998;
Kudo 2003), fire ants (Tschinkel 1988), and leaf-cutting ants
(Wilson 1983). Shortening larval developmental time by direct
contact with the queen may be functionally significant in
newly founded colonies of social Hymenoptera. Specifically,
the rapid and economic production of the first batch of workers
is crucial for the survival of newly founded colonies in the
spring. A model with a similar logic to ours was suggested to
explain size and caste determination in social paper wasps. The
two principal factors in this model were feeding frequency
which is influenced by the number of workers tending the
brood and a growth inhibitory vibration signal to which the
larva is exposed. The vibrations are high early in colony
development and are thought to indicate the presence of a vital
egg-laying female (Brillet et al. 1999; Jeanne and
Suryanarayanan 2011; Suryanarayanan et al. 2011). It is inter-
esting to note that a different situation was reported for some
hemimetabola termites in which egg size is correlated with
adult body size, and the first nymphs (juveniles, comparable in
life stage to larvae in holometabola insects) are larger when
compared with their siblings emerging at later stages of colony
development (Matsuura and Kobayashi 2010). Perhaps the
differences between the social Hymenoptera and the termites
relate to the fact that termite nymphs are part of the working
force of the colony whereas in the holometabolous hymenop-
tera the offspring workers contribute to the work force only as
2
3
4
0 5 10 15 20 25 30 35 40 45 50
Colony age (days after first worker emergence)
Marginalcelllength(mm)
Numberofnurses
% Queen care # Nurses
Percentageofbroodcarebythequeen
100%
50%
0%
25%
75%
Fig. 6 Schematic self-organization model for the influence of brood
care by the queen and worker number on the body size of developing
brood throughout colony development. Double dashed line—the rela-
tive contribution of queen to brood care. Dotted line—the number of
workers nursing the brood. The number of brood tending workers stops
increasing around the time when new workers stop to emerge (around
day 40 in the colony presented in Fig. 1). The gray diamonds and the
dashed regression line were copied from Fig. 1 to show the typical
increase in body size with colony age. The model assumes that the
contact with the queen and worker number determines the body size of
the developing brood
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13. adults. In the social Hymenoptera, rapid development of small
workers might be the most efficient use of the limited resources
of the incipient colony whereas in termites larger nymphs may
have higher survival and can rapidly provide significant con-
tribution to the growth of the colony during the early and
critical founding stage. During later stages of colony develop-
ment in social Hymenoptera, when there are more workers to
collect food, regulate the colony environment, and care for the
brood, it may be beneficial to invest in producing larger bees
that are better foragers (Goulson et al. 2002). The larger and
more effective foragers enable the colony to collect the large
amount of food needed for the production of drones and gynes.
Acknowledgments This work was supported by research grants from
the US–Israel Binational Science Foundation (BSF #2007465), and the
US–Israel Binational Agricultural Research and Development Fund
(BARD #IS-4418-11R) to GB and the “Hoffman Leadership and Re-
sponsibility” fellowship to HS. We thank two anonymous reviewers for
providing helpful comments on a previous version of this manuscript.
References
Alaux C, Jaisson P, Hefetz A (2004) Queen influence on worker
reproduction in bumblebees (Bombus terrestris) colonies. Insect
Soc 51:287–293
Alexander RD (1974) The evolution of social behavior. Annu Rev Ecol
Syst 5:325–383
Alford DV (1975) Bumblebees. Davis-Poynter, London
Beshers SN, Fewell JH (2001) Models of division of labor in social
insects. Annu Rev Entomol 46:413–440
Bloch G (1999) Regulation of queen–worker conflict in bumble-bee
(Bombus terrestris) colonies. Proc R Soc B 266:2465–2469
Brian AD (1952) Division of labour and foraging in Bombus agrorum
Fabricius. J Anim Ecol 21:223–240
Brillet C, Tian-Chansky SS, Le Conte Y (1999) Abdominal waggings and
variation of their rate of occurrence in the social wasp, Polistes
dominulus Christ. I. Quantitative analysis. J Insect Behav 12:665–686
Bryk B, Hahn K, Cohen SM, Teleman AA (2010) MAP4K3 regulates
body size and metabolism in Drosophila. Dev Biol 344:150–157
Calderone NW, Page RE (1991) Evolutionary genetics of division-of-
labor in colonies of the honey-bee (Apis mellifera). Am Nat
138:69–92
Cnaani J, Hefetz A (1994) The effect of workers size frequency distri-
bution on colony development in Bombus terrestris. Insect Soc
41:301–307
Cnaani J, Robinson GE, Bloch G, Borst D, Hefetz A (2000a) The effect
of queen–worker conflict on caste determination in the bumblebee
Bombus terrestris. Behav Ecol Sociobiol 47:346–352
Cnaani J, Robinson GE, Hefetz A (2000b) The critical period for caste
determination in Bombus terrestris and its juvenile hormone cor-
relates. J Comp Physiol A 186:1089–1094
Cnaani J, Hefetz A (2001) Are queen Bombus terrestris giant workers
or are workers dwarf queens? Solving the ‘chicken and egg’
problem in a bumblebee species. Naturwissenschaften 88:85–87
Couvillon MJ, Dornhaus A (2009) Location, location, location: larvae
position inside the nest is correlated with adult body size in worker
bumblebees (Bombus impatiens). Proc Biol Sci 276:2411–2418
Couvillon MJ, Jandt JM, Duong N, Dornhaus A (2010) Ontogeny of
worker body size distribution in bumblebee (Bombus impatiens)
colonies. Ecol Entomol 35:424–435
Cumber RA (1949) The biology of humble-bees, with special reference to
the production of the worker caste. Trans Roy Ent Soc Lond 100:1–45
Davidowitz G, D’Amico LJ, Nijhout HF (2003) Critical weight in the
development of insect body size. Evol Dev 5:188–197
Davidowitz G, D’Amico LJ, Nijhout HF (2004) The effects of envi-
ronmental variation on a mechanism that controls insect body size.
Evol Ecol Res 6:49–62
Duchateau MJ (1989) Agonistic behaviors in colonies of the bumblebee
Bombus terrestris. J Ethol 7:141–151
Duchateau MJ, Hoshiba H, Velthuis HHW (1994) Diploid males in the
bumblebee Bombus terrestris sex determination, sex alleles and
viability. Entomol Exp Appl 71:263–269
Edgar BA (2006) How flies get their size: genetics meets physiology.
Nat Rev Genet 7:907–916
Free JB (1955) The division of labour within bumblebee colonies.
Insect soc 2:195–212
Gerloff CU, Ottmer BK, Schmid-Hempel P (2003) Effects of inbreed-
ing on immune response and body size in a social insect, Bombus
terrestris. Funct Ecol 17:582–589
Goulson D, Peat J, Stout JC, Tucker J, Darvill B, Derwent LC, Hughes
WOH (2002) Can alloethism in workers of the bumblebee,
Bombus terrestris, be explained in terms of foraging efficiency?
Anim Behav 64:123–130
Goulson D (2003) Bumblebees, their behaviour and ecology. Oxford
University Press, New York
Goulson D, Derwent LC, Peat J (2005) Evidence for alloethism in
stingless bees (Meliponinae). Apidologie 36:411–412
Hunt GJ, Guzman-Novoa E, Fondrk MK, Page RE (1998) Quantitative
trait loci for honey bee stinging behavior and body size. Genetics
148:1203–1213
Jandt JM, Huang E, Dornhaus A (2009) Weak specialization of workers
inside a bumble bee (Bombus impatiens) nest. Behav Ecol
Sociobiol 63:1829–1836
Jeanne RL, Suryanarayanan S (2011) A new model for caste develop-
ment in social wasps. Commun Integr Biol 4:373–377
Kamakura M (2011) Royalactin induces queen differentiation in honey
bees. Nature 473:478–483
Kapustjanskij A, Streinzer M, Paulus HF, Spaethe J (2007) Bigger is
better: implications of body size for flight ability under different
light conditions and the evolution of alloethism in bumblebees.
Funct Ecol 21:1130–1136
Knee WJ, Medler JT (1965) Seasonal size increase of bumblebee
workers (Hymenoptera—Bombus). Can Entomol 97:1149–1155
Kudo K (2003) Growth rate and body weight of foundress-reared
offspring in a paper wasp, Polistes chinensis (Hymenoptera,
Vespidae): no influence of food quantity on the first offspring.
Insect Soc 50:77–81
Kupke J, Spaethe J, Mueller MJ, Roessler W, Albert S (2012) Molecular
and biochemical characterization of the major royal jelly protein in
bumblebees suggest a non-nutritive function. Insect Biochem
Molec 42:647–654
Lopez-Vaamonde C, Brown RM, Lucas ER, Pereboom JJM, Jordan
WC, Bourke AFG (2007) Effect of the queen on worker reproduc-
tion and new queen production in the bumblebee Bombus
terrestris. Apidologie 38:171–180
Matsuura K, Kobayashi N (2010) Termite queens adjust egg size
according to colony development. Behav Ecol 21:1018–1023
McBrayer Z, Ono H, Shimell M, Parvy JP, Beckstead RB, Warren JT,
Thummel CS, Dauphin-Villemant C, Gilbert LI, O’Connor MB
(2007) Prothoracicotropic hormone regulates developmental
timing and body size in Drosophila. Dev Cell 13:857–871
Merling M (2008) The influence of task, size and age differences on the
phototactic response in the bumblebee, Bombus terrestris (L.).
Dissertation, The Hebrew University of Jerusalem
Michener CD (1974) The social behavior of bees: a comparative study.
Belknap, Cambridge
Behav Ecol Sociobiol
Author's personal copy
14. Miura T, Matsumoto T (1995) Worker polymorphism and division
of labor in the foraging behavior of the black marching
termite Hospitalitermes medioflavus, on Borneo Island.
Naturwissenschaften 82:564–567
Miyano S (1998) Amount of flesh food influences the number, larval
duration, and body size of first brood workers, in a Japanese paper
wasp, Polistes chinensis antennalis (Hymenoptera: Vespidae).
Entomol Sci 1:545–549
Nijhout HF, Williams CM (1974) Control of moulting and metamor-
phosis in tobacco hornworm, Manduca sexta (L.)—cessation of
juvenile hormone secretion as a trigger for pupation. J Exp Biol
61:493–501
Nijhout H (2003) The control of body size in insects. Dev Biol 261:1–9
Owen RE (1988) Body size variation and optimal body size of bum-
blebee queens (Hymenoptera, Apidae). Can Entomol 120:19–27
Pan DJ (2007) Hippo signaling in organ size control. Gene Dev 21:886–
897
Patel A, Fondrk MK, Kaftanoglu O, Emore C, Hunt G, Frederick K,
Amdam GV (2007) The making of a queen: TOR pathway is a key
player in diphenic caste development. PLoS One 2:e509
Pereboom JJM (2000) The composition of larval food and the signifi-
cance of exocrine secretions in the bumblebee Bombus terrestris.
Insect Soc 47:11–20
Pereboom JJM, Velthuis HHW, Duchateau MJ (2003) The organi-
zation of larval feeding in bumblebees (Hymenoptera, Apidae)
and its significance to caste differentiation. Insect Soc 50:127–
133
Plowright RC, Jay SC (1968) Caste differentiation in bumblebees
(Bombus LTAR.: HYM.) 1.—the determination of female size.
Insect Soc 15:171–192
Pomeroy N, Plowright RC (1982) The relation between worker num-
bers and the production of males and queens in the bumblebee
Bombus perplexus. Can J Zool 60:954–957
Quezada-Euan JJG, Lopez-Velasco A, Perez-Balam J, Moo-Valle H,
Velazquez-Madrazo A, Paxton RJ (2011) Body size differs in
workers produced across time and is associated with variation in
the quantity and composition of larval food in Nannotrigona
perilampoides (Hymenoptera, Meliponini). Insect Soc 58:31–38
Radmacher S, Strohm E (2010) Factors affecting offspring body size in
the solitary bee Osmia bicornis (Hymenoptera, Megachilidae).
Apidologie 41:169–177
Ribeiro MF (1999) Long-duration feedings and caste differentiation in
Bombus terrestris larvae. Insect Soc 46:315–322
Ribeiro MF, Velthuis HHW, Duchateau MJ, van der Tweel I (1999)
Feeding frequency and caste differentiation in Bombus terrestris
larvae. Insect Soc 46:306–314
Robinson GE (1992) Regulation of division of labor in insect societies.
Annu Rev Entomol 37:637–665
Röseler PF (1970) Differences in caste determination between bumble-
bee species Bombus hypnorum and Bombus terrestris. Z
Naturforsch Pt B 25:543–548
Roulston TH, Cane JH (2000) The effect of diet breadth and nesting
ecology on body size variation in bees (Apiformes). J Kansas
Entomol Soc 73:129–142
Roulston TH, Cane JH (2002) The effect of pollen protein concentration
on body size in the sweat bee Lasioglossum zephyrum (Hymenop-
tera: Apiformes). Evol Ecol 16:49–65
Schmid-Hempel R, Schmid-Hempel P (2000) Female mating frequen-
cies in Bombus spp. from Central Europe. Insect Soc 47:36–41
Schwander T, Humbert JY, Brent CS, Cahan SH, Chapuis L, Renai E,
Keller L (2008) Maternal effect on female caste determination in a
social insect. Curr Biol 18:265–269
Schwander T, Lo N, Beekman M, Oldroyd BP, Keller L (2010) Nature
versus nurture in social insect caste differentiation. Trends Ecol
Evol 25:275–282
Seeley TD, Kolmes SA (1991) Age polyethism for hive duties in honey
bees ‐ illusion or reality? Ethology 87:284–297
Smith CR, Toth AL, Suarez AV, Robinson GE (2008) Genetic and
genomic analyses of the division of labour in insect societies.
Nat Rev Genet 9:735–748
Spaethe J, Weidenmuller A (2002) Size variation and foraging rate in
bumblebees (Bombus terrestris). Insect Soc 49:142–146
Spaethe J, Chittka L (2003) Interindividual variation of eye optics and
single object resolution in bumblebees. J Exp Biol 206:3447–3453
Spaethe J, Brockmann A, Halbig C, Tautz J (2007) Size determines
antennal sensitivity and behavioral threshold to odors in bumble-
bee workers. Naturwissenschaften 94:733–739
Suryanarayanan S, Hantschel AE, Torres CG, Jeanne RL (2011)
Changes in the temporal pattern of antennal drumming behavior
across the Polistes fuscatus colony cycle (Hymenoptera,
Vespidae). Insect Soc 58:97–106
Sutcliffe GH, Plowright RC (1990) The effects of pollen availability on
development time in the bumblebee Bombus terricola K. (Hyme-
noptera, Apidae). Can J Zool 68:1120–1123
Suzzoni JP, Passera L, Strambi A (1980) Ecdysteroid titer and caste
determination in the ant, Pheidole pallidula (NYL) (Hymenoptera,
Formicidae). Experientia 36:1228–1229
Tasei JN, Aupinel P (2008) Nutritive value of 15 single pollens and pollen
mixes tested on larvae produced by bumblebee workers (Bombus
terrestris, Hymenoptera: Apidae). Apidologie 39:397–409
Tschinkel WR (1988) Colony growth and the ontogeny of worker
polymorphism in the fire ant, Solenopsis invicta. Behav Ecol
Sociobiol 22:103–115
Weiss R, Dov A, Fahrbach SE, Bloch G (2009) Body size‐related
variation in Pigment Dispersing Factor‐immunoreactivity in the
brain of the bumblebee Bombus terrestris (Hymenoptera, Apidae).
J Insect Physiol 55:479–487
Wheeler DE, Nijhout HF (1981) Soldier determination in ants—new
role for juvenile hormone. Science 213:361–363
Wilson EO (1971) The insect societies. Belknap, Cambridge
Wilson EO (1978) Division of labor in fire ants based on physical castes
(Hymenoptera: Formicidae: Solenopsis). J Kansas Entomol Soc
51:615–636
Wilson EO (1983) Caste and division of labor in leaf-cutter ants (Hy-
menoptera, Formicidae, Atta). 4. Colony ontogeny of Atta
cephalotes. Behav Ecol Sociobiol 14:55–60
Wolschin F, Shpigler H, Amdam GV, Bloch G (2012) Size-related
variation in protein abundance in the brain and abdominal tissue
of bumble bee workers. Insect Mol Biol 21:319–325
Woodard HS, Bloch G, Band M, Robinson GE (2013) Social regulation
of maternal traits in nest-founding bumble bee (Bombus terrestris)
queens. J Exp Biol (in press).
Worden BD, Skemp AK, Papaj DR (2005) Learning in two contexts:
the effects of interference and body size in bumblebees. J Exp Biol
208:2045–2053
Yerushalmi S, Bodenhaimer S, Bloch G (2006) Developmentally de-
termined attenuation in circadian rhythms links chronobiology to
social organization in bees. J Exp Biol 209:1044–1051
Behav Ecol Sociobiol
Author's personal copy