This document summarizes research on the marine snail Littoraria irrorata and its relationship with fungi in salt marshes. The key points are:
1. Surveys along the Atlantic coast found that L. irrorata commonly grazes live marsh grass, creating wounds that are colonized by fungi, unlike undamaged grass surfaces.
2. Experiments showed this is a facultative mutualism, as snails promote fungal growth through grazing and depositing feces rich in fungal hyphae, and consume the invasive fungi for food.
3. Fungal removal experiments indicate snails and fungi act together to suppress marsh grass production, revealing a mechanism by which grazers control plant
An Overview on Microorganisms Contribute in Increasing Soil FertilitySafi Ur Rehman Qamar
Microorganisms play an important role in increasing soil fertility. They decompose organic matter into simpler nutrients that plants can absorb, improving soil quality. Microbes incorporate minerals and nitrogen into the soil, transforming waste land into productive soil. The variety and quantity of microbes depends on the physical and chemical properties of the soil. Different microorganisms decompose different types of organic matter, producing nutrients. Both bacteria and fungi increase soil fertility through organic matter decomposition. Microorganisms are essential for nutrient cycling in soil and supporting plant growth.
root microbial interaction for crop improvement seminar ppt Balaji Rathod
This document discusses root-microbial interactions and how they impact crop improvement. It covers how plant root exudates can influence both positive and negative interactions with other plants and microbes. On the plant-plant side, exudates can facilitate resource competition, allelopathy, or parasitic relationships. Positively, they may induce defenses in neighboring plants. With microbes, exudates enable symbiotic relationships like nitrogen fixation and mycorrhizal associations, but can also have antimicrobial effects against pathogens. A better understanding of these below-ground processes could help develop strategies to enhance soil health and crop yields.
B.sc. agri sem ii agricultural microbiology unit 2 soil microorganismsRai University
The document discusses the various microorganisms found in soil, including bacteria, actinomycetes, fungi, algae, protozoa, and higher animal forms. It describes the different groups of bacteria and microorganisms, their roles in soil processes like decomposition and nutrient cycling, and how they vary depending on environmental conditions. Methods for enumerating and classifying soil microorganisms are also summarized.
This document provides an overview of domoic acid, a marine biotoxin produced by the diatom genus Pseudo-nitzschia. It discusses several cases of domoic acid poisoning in humans and marine wildlife from 1987 onward. The toxin causes amnesic shellfish poisoning in humans. Pseudo-nitzschia blooms can occur under various environmental conditions and seem to be increasing due to coastal pollution and global warming. Domoic acid production is related to nutrient availability and trace metals. While its biological function is unknown, it may serve as a way to eliminate excess energy or bind trace metals.
Diversity of Soil Fauna and Ecosystem Function tariqulmasud12
Soils are natural resources of utmost. Importance for a number of ecosystem and biosphere processes such as plant production, cycling of organic matter and nutrients, storage of C and water, and release of nitrous oxides, CO2 and methane. Soil degradation, through various processes, is a matter of great concern, since their integrity is absolutely critical to increasing food production (FAO, 1995), and regulating atmospheric fluxes of greenhouse gases (Jenkinson, 199 1 ; Wallace, 1994).
1) The document discusses soil organisms, their classification, functions, and role in soil fertility. It describes bacteria, fungi, actinomycetes, algae, protozoa, nematodes, earthworms, ants and other micro and macro fauna found in soil.
2) These organisms play important roles like decomposing organic matter, recycling nutrients, fixing nitrogen, controlling pests and diseases, and creating soil structure and humus. Their interactions and biological processes regulate soil health.
3) Tests like Neubauer seedling, Sacket and Stewart techniques are used to evaluate soil fertility based on biological parameters like microbial population and activity. Some organisms can also harm plants through diseases, competition
This document discusses the role of fungal endophytes in Cannabis sativa and their potential medical value. It introduces fungal endophytes as microorganisms that live within plant tissues without causing disease. Up to 30 fungal endophytes have been isolated from C. sativa. Fungal endophytes provide benefits to plants like stress tolerance and production of similar secondary metabolites. They may play a role in the vast number of unique metabolites found in C. sativa, including the 150+ cannabinoids that are not found elsewhere. The presence or absence of compounds can vary by geological location of C. sativa, suggesting endophytes available differ by region. The document argues the fungal endophytes
This document discusses the role of chemical ecology, volatile compounds, and secondary plant substances in plant resistance to insects. It provides background on chemical ecology and how plant chemicals can affect insect behavior. Secondary plant metabolites like alkaloids, terpenoids, and phenolic compounds adversely impact insect growth, development, and metabolism. Specific examples are given of compounds that act as feeding deterrents or have toxic effects on insects. The document also discusses how plant volatile compounds can attract or repel insects.
An Overview on Microorganisms Contribute in Increasing Soil FertilitySafi Ur Rehman Qamar
Microorganisms play an important role in increasing soil fertility. They decompose organic matter into simpler nutrients that plants can absorb, improving soil quality. Microbes incorporate minerals and nitrogen into the soil, transforming waste land into productive soil. The variety and quantity of microbes depends on the physical and chemical properties of the soil. Different microorganisms decompose different types of organic matter, producing nutrients. Both bacteria and fungi increase soil fertility through organic matter decomposition. Microorganisms are essential for nutrient cycling in soil and supporting plant growth.
root microbial interaction for crop improvement seminar ppt Balaji Rathod
This document discusses root-microbial interactions and how they impact crop improvement. It covers how plant root exudates can influence both positive and negative interactions with other plants and microbes. On the plant-plant side, exudates can facilitate resource competition, allelopathy, or parasitic relationships. Positively, they may induce defenses in neighboring plants. With microbes, exudates enable symbiotic relationships like nitrogen fixation and mycorrhizal associations, but can also have antimicrobial effects against pathogens. A better understanding of these below-ground processes could help develop strategies to enhance soil health and crop yields.
B.sc. agri sem ii agricultural microbiology unit 2 soil microorganismsRai University
The document discusses the various microorganisms found in soil, including bacteria, actinomycetes, fungi, algae, protozoa, and higher animal forms. It describes the different groups of bacteria and microorganisms, their roles in soil processes like decomposition and nutrient cycling, and how they vary depending on environmental conditions. Methods for enumerating and classifying soil microorganisms are also summarized.
This document provides an overview of domoic acid, a marine biotoxin produced by the diatom genus Pseudo-nitzschia. It discusses several cases of domoic acid poisoning in humans and marine wildlife from 1987 onward. The toxin causes amnesic shellfish poisoning in humans. Pseudo-nitzschia blooms can occur under various environmental conditions and seem to be increasing due to coastal pollution and global warming. Domoic acid production is related to nutrient availability and trace metals. While its biological function is unknown, it may serve as a way to eliminate excess energy or bind trace metals.
Diversity of Soil Fauna and Ecosystem Function tariqulmasud12
Soils are natural resources of utmost. Importance for a number of ecosystem and biosphere processes such as plant production, cycling of organic matter and nutrients, storage of C and water, and release of nitrous oxides, CO2 and methane. Soil degradation, through various processes, is a matter of great concern, since their integrity is absolutely critical to increasing food production (FAO, 1995), and regulating atmospheric fluxes of greenhouse gases (Jenkinson, 199 1 ; Wallace, 1994).
1) The document discusses soil organisms, their classification, functions, and role in soil fertility. It describes bacteria, fungi, actinomycetes, algae, protozoa, nematodes, earthworms, ants and other micro and macro fauna found in soil.
2) These organisms play important roles like decomposing organic matter, recycling nutrients, fixing nitrogen, controlling pests and diseases, and creating soil structure and humus. Their interactions and biological processes regulate soil health.
3) Tests like Neubauer seedling, Sacket and Stewart techniques are used to evaluate soil fertility based on biological parameters like microbial population and activity. Some organisms can also harm plants through diseases, competition
This document discusses the role of fungal endophytes in Cannabis sativa and their potential medical value. It introduces fungal endophytes as microorganisms that live within plant tissues without causing disease. Up to 30 fungal endophytes have been isolated from C. sativa. Fungal endophytes provide benefits to plants like stress tolerance and production of similar secondary metabolites. They may play a role in the vast number of unique metabolites found in C. sativa, including the 150+ cannabinoids that are not found elsewhere. The presence or absence of compounds can vary by geological location of C. sativa, suggesting endophytes available differ by region. The document argues the fungal endophytes
This document discusses the role of chemical ecology, volatile compounds, and secondary plant substances in plant resistance to insects. It provides background on chemical ecology and how plant chemicals can affect insect behavior. Secondary plant metabolites like alkaloids, terpenoids, and phenolic compounds adversely impact insect growth, development, and metabolism. Specific examples are given of compounds that act as feeding deterrents or have toxic effects on insects. The document also discusses how plant volatile compounds can attract or repel insects.
This document discusses methods for analyzing microbial diversity in soil without culturing. It notes that while culturing methods have provided access to some microbes, they represent only about 1% of soil microbes due to physiological constraints. Molecular methods like 16S rRNA gene sequencing reveal far greater phylogenetic diversity in soil. The document reviews various culture-independent methods like DNA-DNA hybridization, PCR amplification, and gene expression cloning that provide insights into the phylogenetic and functional diversity of uncultured soil microbes, opening possibilities for discovering novel products. It suggests both culturable and unculturable microbes likely contribute to untapped natural product resources.
This document discusses insect biodiversity and conservation. It begins by defining biodiversity and noting that insects make up over 70% of described species. It then provides tables listing the approximate number of described species across taxonomic groups. The rest of the document discusses measuring and comparing diversity within and between communities, the importance of conserving insect diversity for ecosystem services like pollination and pest control, and threats to biodiversity from land use change, climate change, and invasive species.
many microorganisms from the soil are still undiscovered, while most of the discovered microbes cannot be cultivated in the artificial medium due to various reasons. This is briefly discussed in this presentation.
This document discusses keystone species and provides examples from Robert Paine's research. It begins by defining a keystone species as one that has a large effect on the community despite its low abundance. It then summarizes Paine's seminal experiments in the 1960s where he found that removing the predatory sea star Pisaster ochraceous from an intertidal zone led to a decline in species diversity from 15 to 8 species due to competitive exclusion. The document concludes by outlining different types of keystone species including keystone carnivores, seed predators, mutualists, herbivores, plants, and prey.
The document discusses keystone species and provides examples. It defines a keystone species as a plant or animal that plays a unique and crucial role in ecosystem function. Without it, the ecosystem would be dramatically different or cease to exist. It gives the example of wolves in Yellowstone, whose reintroduction led to thriving populations of many other species. The concept of keystone species was established in 1969 by Robert Paine through his research on sea stars. Keystone species are often predators that control prey populations, like mountain lions, or herbivores that shape habitats, like elephants in Serengeti. The disappearance of a keystone species can start a domino effect leading to ecosystem failure.
This document discusses mycorrhizal fungi and nematophagous fungi. It begins by introducing mycorrhizae as a symbiotic relationship between fungi and plant roots. It then describes different types of mycorrhizal associations like ectomycorrhizae, endomycorrhizae, and arbuscular mycorrhizae. It also discusses the benefits of mycorrhizal relationships for both plants and fungi. The document then introduces nematodes and nematophagous fungi, which prey on nematodes through trapping mechanisms like adhesive hyphae or nets.
The document discusses the concepts of keystone and foundation species through several examples. It describes research showing that the sea star Pisaster ochraceus is a keystone species that controls populations of mussels, maintaining diversity in intertidal communities. Studies on kangaroo rats and prairie dogs also demonstrate how removing these species can transform ecosystems by reducing diversity. Kelp is provided as an example of a foundation species as a dominant primary producer.
Trends in Macrophyte Diversity in Anthropogenic Perturbed Lentic Ecosystems w...Premier Publishers
Aquatic macrophytes hold several niches within the ecosystem, including inter alia water purification, carbon sequestration and serve as microhabitats for aquatic insects. These dynamic roles make macrophytes good indicators of current environmental conditions. Hence assessing their abundance in line with wetland ecosystem dynamics and function is essential. Frequency of occurrence and density values were estimated, using twenty (20) 2 m x 2 m quadrats for each macrophyte encountered. The results of the study revealed twenty-one (21) macrophytes belonging to 16 families. These ponds varied markedly in terms of species composition and in numerical strength such that Polygonum lanigerum (1143+175st/ha), Setaria verticillata (337.5+ 32.8st/ha), Azolla pinnata (337.7+ 16.4 st/ha) recorded high density values while Lagenaria breviflora (18.7±2.19), Sida acuta (18.75±5.30), Ludwigia erecta (18.7±0.15) and Milletia aboensis (18.7±0.03) were the least abundant species. Pond A and D with 11 taxa each had the higher Shannon-Wiener (2.192, 2.214) and Simpson (0.8699, 0.8787) diversity indices respectively when compared to the other ponds. On the contrary, pond C with four taxa had the least Shannon-Wiener and Simpson diversity indices (1.253, 0.6782) respectively. Equitability and evenness ranged between 0.914 - 0. 952 and 0.814 - 0.900 respectively. Bray and Curtis cluster analysis showed that pond B was the most dissimilar compared to other ponds in terms of the taxa composition.
Ingoldian Fungi in Kigga Falls, Chikmagalur District, KarnatakaIOSR Journals
Fungi are the ubiquitous organism.The exist in diverse forms in a range of habitats, arboreal,
freshwater, marine, subterranean and terrestrial. In fresh water we concentrated only Ingoldian fungi. The
selected study sites of foam samples and decaying debris were collected in the same study area and kept for
screening and incubation respectively. The conidia developing on decayingdebris were screened using
microscope. The collected foam samples were revealed Ingoldian fungi. In this contribution of occurrence and
abundance of Ingoldian fungi were enumerated. A total of 24 species were isolated twelve genera were
identified.
This document outlines the course content for Insect Ecology and Integrated Pest Management. It includes objectives to impart knowledge on insect ecology and integrated pest management. The theory section will cover ecological factors influencing insects, IPM components, classification of insecticides. Practicals include sampling techniques, identification of pests and biological control agents, and mass multiplication of biocontrol agents. The document provides lecture outlines covering topics such as ecology, abiotic factors, IPM, host plant resistance, and management methods.
The document provides an overview of key concepts in community ecology, including species interactions, trophic levels, food webs, succession, biomes, and factors that limit population growth. It defines important ecological terms and describes various types of species relationships, ecological roles, community changes over time, and Earth's major terrestrial biomes.
This document discusses biodiversity at multiple levels - genetic, species, and ecosystem diversity. It notes that biodiversity represents the variety of life forms from unicellular to multicellular organisms across all biological levels. Species diversity is largest among small organisms like insects and fungi. The document highlights that we have only described 15% of terrestrial species and 9% of marine species, showing how much biodiversity remains unknown. It also discusses the value of biodiversity through the ecosystem services it provides like nutrient cycling, soil conditioning, climate regulation, and providing natural resources for food, medicine and other uses. Maintaining biodiversity acts as an environmental insurance and ensures ecosystem resilience.
This study aims to determine if the native herbivore Tansyphyrus lemnae shows a preference for native duckweed species over the invasive Lemna minuta. The study will compare the feeding rates of T. lemnae on L. minor, Spirodela polyrhiza, and L. minuta, and assess the impact of herbivory on the growth of L. minor and L. minuta. The results could provide insight into how L. minuta gains a competitive advantage by facing less pressure from native herbivores.
- The study examined the impacts of insect herbivory on population dynamics of tree cholla cactus across an elevational gradient in New Mexico.
- Insect herbivore abundance and damage to cacti decreased with increasing elevation, inversely correlated with cactus density.
- Experimental exclusion of insects showed their negative effects on cactus growth and seed production were strongest at low elevation and decreased at higher elevations.
- Demographic modeling predicted insect herbivory depressed population growth rates the most at low elevation, less so at mid elevation, and hardly at high elevation.
This study examined the effect of weed management on insect natural enemies in cabbage fields. Two cabbage fields were studied, one where herbicides were used to control weeds, and one where weeds were allowed to grow freely. More insect natural enemies were found in the field without herbicides compared to the field with herbicides. Five species of predatory insects were collected from both fields. Four common weed species were also identified in the field without herbicides that may provide resources like nectar and pollen to support more natural enemies. The results suggest that maintaining some weeds can help enhance natural enemy populations and potentially suppress insect pests in cabbage fields.
Aquatic Insect Similarity Connecting Natural Wetland Habitat and Ricefield fo...Innspub Net
This study describes the relationship of the natural wetland habitats in Agusan Marsh to nearby rice fields and its implication to ecological rice production. Aquatic insects play multiple roles in the ecosystem such as predators, prey to other animals and decomposers which help in maintaining ecological balance. Results revealed that the diversity of odonates was highest in the sedge-dominated swamp among natural habitats which corresponds to the adjoining ricefields. The pattern of clustering of odonates show 3 groups; the rice-sago and rice-sedges sub-cluster, the rice-bangkal, rice-Terminalia, rice-fern, bangkal, sago and sedges sub-cluster, and the Terminalia forest as the outlier. The diversity of semi-aquatic and aquatic bugs was highest in the Bangkal forest while the lowest was in the fern-dominated swamp. The pattern of clustering shows 2 sub-clusters and the outlier Bangkal forest. On aquatic beetles, highest diversity was in the Terminalia forest. The sub-cluster consists of Terminalia habitat and rice-fern, while the other sub-cluster includes rice-Bangkal and rice-Terminalia. The resulting patterns of similarity in diversity and distribution of species in natural habitats and nearby ricefields indicate that ricefields are important temporary habitats for some aquatic insect species and serve as stepping stones for the movement of the insects.
assessing heterogeneous influences on partial deposition of virus in lateriticIJCMESJOURNAL
This paper monitored the rate of partial deposition of virus on heterogeneous formation, the study were able to monitor the behaviour of virus in heterogeneous deposition influencing partial concentration of virus in Lateritic and silty formation. The study was able to observe the rate of partial deposition base on its rate of fluctuation through variation observed from deposited void ratio and permeability, such formation developed fluctuation on these parameters thus generated partial deposition of virus in the study area. Linear deposition were also experienced in graphical representation, the result obtained ranged from [1.97E-12-2.35E-11],[3-30M], [1.97E-12-2.36E-11[10-100] Predictive 1.97E-12, Experimental 1.87E-12 [3-36m], predictive, [1,97E-12], Experimental [2.26E-11] [10-120 Days] predictive 2.36E-12, Experimental 2.24E-11,[10-120Days] [1.31E-12-2.36E11], Predictive1.31E-12, Experimental, 2.36E-11 [2-30m], predictive,[2.36E-11-2.2E-11]; [2-30m] ,for Time 1.31E-12-2.36E-11[4-60days] while predictive and Experimental,[2,36E-11] [1.37E-12-2,22E-11] [2-30m] The prediction rate of partial deposition of virus was possible through mathematical modeling techniques, the system were developed base on the parameters from predominant formation characteristics in study location, these parameters generated the derived model through the developed governing equation, simulation generated theoretical values that were compared with experimental results, both parameters developed best fits validating the model, experts will definitely applied this approach in monitoring and evaluation of virus deposits in the study area.
Arbuscular mycorrhizal fungi (Glomus mosseae) selection by date palm root sys...AI Publications
In Jerid region pedoclimatic conditions and agricultural practices are of major importance in shaping the arbuscular mycorrhizal fungi in the rhizophere of date palm tree. Glomus mosseae (dominant species) isolated from soil was multiplied and used as inoculum for date palm seedling. For this study, a pot experiment was conducted under greenhouse condition to assess the effect of inoculation with arbuscular mycorhizal fungus (Glomus mosseae) and mycorrhizal soil (substrate containing the propagules) compared to control seedlings. The result of analysis carried out in this work revealed that the addition of mycorrhizal fungi (Glomus mosseae) and mycorrhizal soil allowed us to conclude that the increase in phosphorus and nitrogen availability in soil solutions leads to a decrease in mycorhization rate and vice versa. Furthermore there is a good correlation between these two parameters. The levels of exchangeable calcium and magnesium tend to increase slightly over time estimated that their absorption mechanism is the same as for phosphorus. The absorption of these elements often difficult to assimilate by the plant is improved by the mycorrhizal association. That is to say, the increase in their removal is mainly due to better exploration of the soil by extra-rooted hyphae. In addition, endomycorrhizae are much less influenced by certain interactions between soil elements. Greenhouse experiments clearly show that artificial inoculation with mycorrhizal soil and spores (Glomus mosseae) has led to an improvement in the fertility of soils used as a substrate for culture, with a superiority of infection caused by mycorrhizal soil.
1) The document reviews the symbiotic relationship between the Hawaiian bobtail squid (Euprymna scolopes) and the bioluminescent bacterium Vibrio fischeri.
2) It describes how within hours of hatching, the squid is able to selectively colonize its light organ only with V. fischeri from the diverse microbial environment.
3) This selectivity is achieved through a multi-step process ("winnowing") where the squid's ciliated epithelia initially allow some bacteria to enter its light organ crypts, but then a restrictive period ensures only V. fischeri persists to form the exclusive symbiosis.
The document discusses SAS High-Performance Analytics, a product that leverages in-memory architecture through a dedicated software and hardware appliance to drive high-performance analytics. It highlights how the product addresses the entire analytical lifecycle from data exploration to model deployment to achieve insights at breakthrough speed. Key differentiators of the product include being the only in-memory offering that can develop and deploy high-end analytics models.
This document discusses methods for analyzing microbial diversity in soil without culturing. It notes that while culturing methods have provided access to some microbes, they represent only about 1% of soil microbes due to physiological constraints. Molecular methods like 16S rRNA gene sequencing reveal far greater phylogenetic diversity in soil. The document reviews various culture-independent methods like DNA-DNA hybridization, PCR amplification, and gene expression cloning that provide insights into the phylogenetic and functional diversity of uncultured soil microbes, opening possibilities for discovering novel products. It suggests both culturable and unculturable microbes likely contribute to untapped natural product resources.
This document discusses insect biodiversity and conservation. It begins by defining biodiversity and noting that insects make up over 70% of described species. It then provides tables listing the approximate number of described species across taxonomic groups. The rest of the document discusses measuring and comparing diversity within and between communities, the importance of conserving insect diversity for ecosystem services like pollination and pest control, and threats to biodiversity from land use change, climate change, and invasive species.
many microorganisms from the soil are still undiscovered, while most of the discovered microbes cannot be cultivated in the artificial medium due to various reasons. This is briefly discussed in this presentation.
This document discusses keystone species and provides examples from Robert Paine's research. It begins by defining a keystone species as one that has a large effect on the community despite its low abundance. It then summarizes Paine's seminal experiments in the 1960s where he found that removing the predatory sea star Pisaster ochraceous from an intertidal zone led to a decline in species diversity from 15 to 8 species due to competitive exclusion. The document concludes by outlining different types of keystone species including keystone carnivores, seed predators, mutualists, herbivores, plants, and prey.
The document discusses keystone species and provides examples. It defines a keystone species as a plant or animal that plays a unique and crucial role in ecosystem function. Without it, the ecosystem would be dramatically different or cease to exist. It gives the example of wolves in Yellowstone, whose reintroduction led to thriving populations of many other species. The concept of keystone species was established in 1969 by Robert Paine through his research on sea stars. Keystone species are often predators that control prey populations, like mountain lions, or herbivores that shape habitats, like elephants in Serengeti. The disappearance of a keystone species can start a domino effect leading to ecosystem failure.
This document discusses mycorrhizal fungi and nematophagous fungi. It begins by introducing mycorrhizae as a symbiotic relationship between fungi and plant roots. It then describes different types of mycorrhizal associations like ectomycorrhizae, endomycorrhizae, and arbuscular mycorrhizae. It also discusses the benefits of mycorrhizal relationships for both plants and fungi. The document then introduces nematodes and nematophagous fungi, which prey on nematodes through trapping mechanisms like adhesive hyphae or nets.
The document discusses the concepts of keystone and foundation species through several examples. It describes research showing that the sea star Pisaster ochraceus is a keystone species that controls populations of mussels, maintaining diversity in intertidal communities. Studies on kangaroo rats and prairie dogs also demonstrate how removing these species can transform ecosystems by reducing diversity. Kelp is provided as an example of a foundation species as a dominant primary producer.
Trends in Macrophyte Diversity in Anthropogenic Perturbed Lentic Ecosystems w...Premier Publishers
Aquatic macrophytes hold several niches within the ecosystem, including inter alia water purification, carbon sequestration and serve as microhabitats for aquatic insects. These dynamic roles make macrophytes good indicators of current environmental conditions. Hence assessing their abundance in line with wetland ecosystem dynamics and function is essential. Frequency of occurrence and density values were estimated, using twenty (20) 2 m x 2 m quadrats for each macrophyte encountered. The results of the study revealed twenty-one (21) macrophytes belonging to 16 families. These ponds varied markedly in terms of species composition and in numerical strength such that Polygonum lanigerum (1143+175st/ha), Setaria verticillata (337.5+ 32.8st/ha), Azolla pinnata (337.7+ 16.4 st/ha) recorded high density values while Lagenaria breviflora (18.7±2.19), Sida acuta (18.75±5.30), Ludwigia erecta (18.7±0.15) and Milletia aboensis (18.7±0.03) were the least abundant species. Pond A and D with 11 taxa each had the higher Shannon-Wiener (2.192, 2.214) and Simpson (0.8699, 0.8787) diversity indices respectively when compared to the other ponds. On the contrary, pond C with four taxa had the least Shannon-Wiener and Simpson diversity indices (1.253, 0.6782) respectively. Equitability and evenness ranged between 0.914 - 0. 952 and 0.814 - 0.900 respectively. Bray and Curtis cluster analysis showed that pond B was the most dissimilar compared to other ponds in terms of the taxa composition.
Ingoldian Fungi in Kigga Falls, Chikmagalur District, KarnatakaIOSR Journals
Fungi are the ubiquitous organism.The exist in diverse forms in a range of habitats, arboreal,
freshwater, marine, subterranean and terrestrial. In fresh water we concentrated only Ingoldian fungi. The
selected study sites of foam samples and decaying debris were collected in the same study area and kept for
screening and incubation respectively. The conidia developing on decayingdebris were screened using
microscope. The collected foam samples were revealed Ingoldian fungi. In this contribution of occurrence and
abundance of Ingoldian fungi were enumerated. A total of 24 species were isolated twelve genera were
identified.
This document outlines the course content for Insect Ecology and Integrated Pest Management. It includes objectives to impart knowledge on insect ecology and integrated pest management. The theory section will cover ecological factors influencing insects, IPM components, classification of insecticides. Practicals include sampling techniques, identification of pests and biological control agents, and mass multiplication of biocontrol agents. The document provides lecture outlines covering topics such as ecology, abiotic factors, IPM, host plant resistance, and management methods.
The document provides an overview of key concepts in community ecology, including species interactions, trophic levels, food webs, succession, biomes, and factors that limit population growth. It defines important ecological terms and describes various types of species relationships, ecological roles, community changes over time, and Earth's major terrestrial biomes.
This document discusses biodiversity at multiple levels - genetic, species, and ecosystem diversity. It notes that biodiversity represents the variety of life forms from unicellular to multicellular organisms across all biological levels. Species diversity is largest among small organisms like insects and fungi. The document highlights that we have only described 15% of terrestrial species and 9% of marine species, showing how much biodiversity remains unknown. It also discusses the value of biodiversity through the ecosystem services it provides like nutrient cycling, soil conditioning, climate regulation, and providing natural resources for food, medicine and other uses. Maintaining biodiversity acts as an environmental insurance and ensures ecosystem resilience.
This study aims to determine if the native herbivore Tansyphyrus lemnae shows a preference for native duckweed species over the invasive Lemna minuta. The study will compare the feeding rates of T. lemnae on L. minor, Spirodela polyrhiza, and L. minuta, and assess the impact of herbivory on the growth of L. minor and L. minuta. The results could provide insight into how L. minuta gains a competitive advantage by facing less pressure from native herbivores.
- The study examined the impacts of insect herbivory on population dynamics of tree cholla cactus across an elevational gradient in New Mexico.
- Insect herbivore abundance and damage to cacti decreased with increasing elevation, inversely correlated with cactus density.
- Experimental exclusion of insects showed their negative effects on cactus growth and seed production were strongest at low elevation and decreased at higher elevations.
- Demographic modeling predicted insect herbivory depressed population growth rates the most at low elevation, less so at mid elevation, and hardly at high elevation.
This study examined the effect of weed management on insect natural enemies in cabbage fields. Two cabbage fields were studied, one where herbicides were used to control weeds, and one where weeds were allowed to grow freely. More insect natural enemies were found in the field without herbicides compared to the field with herbicides. Five species of predatory insects were collected from both fields. Four common weed species were also identified in the field without herbicides that may provide resources like nectar and pollen to support more natural enemies. The results suggest that maintaining some weeds can help enhance natural enemy populations and potentially suppress insect pests in cabbage fields.
Aquatic Insect Similarity Connecting Natural Wetland Habitat and Ricefield fo...Innspub Net
This study describes the relationship of the natural wetland habitats in Agusan Marsh to nearby rice fields and its implication to ecological rice production. Aquatic insects play multiple roles in the ecosystem such as predators, prey to other animals and decomposers which help in maintaining ecological balance. Results revealed that the diversity of odonates was highest in the sedge-dominated swamp among natural habitats which corresponds to the adjoining ricefields. The pattern of clustering of odonates show 3 groups; the rice-sago and rice-sedges sub-cluster, the rice-bangkal, rice-Terminalia, rice-fern, bangkal, sago and sedges sub-cluster, and the Terminalia forest as the outlier. The diversity of semi-aquatic and aquatic bugs was highest in the Bangkal forest while the lowest was in the fern-dominated swamp. The pattern of clustering shows 2 sub-clusters and the outlier Bangkal forest. On aquatic beetles, highest diversity was in the Terminalia forest. The sub-cluster consists of Terminalia habitat and rice-fern, while the other sub-cluster includes rice-Bangkal and rice-Terminalia. The resulting patterns of similarity in diversity and distribution of species in natural habitats and nearby ricefields indicate that ricefields are important temporary habitats for some aquatic insect species and serve as stepping stones for the movement of the insects.
assessing heterogeneous influences on partial deposition of virus in lateriticIJCMESJOURNAL
This paper monitored the rate of partial deposition of virus on heterogeneous formation, the study were able to monitor the behaviour of virus in heterogeneous deposition influencing partial concentration of virus in Lateritic and silty formation. The study was able to observe the rate of partial deposition base on its rate of fluctuation through variation observed from deposited void ratio and permeability, such formation developed fluctuation on these parameters thus generated partial deposition of virus in the study area. Linear deposition were also experienced in graphical representation, the result obtained ranged from [1.97E-12-2.35E-11],[3-30M], [1.97E-12-2.36E-11[10-100] Predictive 1.97E-12, Experimental 1.87E-12 [3-36m], predictive, [1,97E-12], Experimental [2.26E-11] [10-120 Days] predictive 2.36E-12, Experimental 2.24E-11,[10-120Days] [1.31E-12-2.36E11], Predictive1.31E-12, Experimental, 2.36E-11 [2-30m], predictive,[2.36E-11-2.2E-11]; [2-30m] ,for Time 1.31E-12-2.36E-11[4-60days] while predictive and Experimental,[2,36E-11] [1.37E-12-2,22E-11] [2-30m] The prediction rate of partial deposition of virus was possible through mathematical modeling techniques, the system were developed base on the parameters from predominant formation characteristics in study location, these parameters generated the derived model through the developed governing equation, simulation generated theoretical values that were compared with experimental results, both parameters developed best fits validating the model, experts will definitely applied this approach in monitoring and evaluation of virus deposits in the study area.
Arbuscular mycorrhizal fungi (Glomus mosseae) selection by date palm root sys...AI Publications
In Jerid region pedoclimatic conditions and agricultural practices are of major importance in shaping the arbuscular mycorrhizal fungi in the rhizophere of date palm tree. Glomus mosseae (dominant species) isolated from soil was multiplied and used as inoculum for date palm seedling. For this study, a pot experiment was conducted under greenhouse condition to assess the effect of inoculation with arbuscular mycorhizal fungus (Glomus mosseae) and mycorrhizal soil (substrate containing the propagules) compared to control seedlings. The result of analysis carried out in this work revealed that the addition of mycorrhizal fungi (Glomus mosseae) and mycorrhizal soil allowed us to conclude that the increase in phosphorus and nitrogen availability in soil solutions leads to a decrease in mycorhization rate and vice versa. Furthermore there is a good correlation between these two parameters. The levels of exchangeable calcium and magnesium tend to increase slightly over time estimated that their absorption mechanism is the same as for phosphorus. The absorption of these elements often difficult to assimilate by the plant is improved by the mycorrhizal association. That is to say, the increase in their removal is mainly due to better exploration of the soil by extra-rooted hyphae. In addition, endomycorrhizae are much less influenced by certain interactions between soil elements. Greenhouse experiments clearly show that artificial inoculation with mycorrhizal soil and spores (Glomus mosseae) has led to an improvement in the fertility of soils used as a substrate for culture, with a superiority of infection caused by mycorrhizal soil.
1) The document reviews the symbiotic relationship between the Hawaiian bobtail squid (Euprymna scolopes) and the bioluminescent bacterium Vibrio fischeri.
2) It describes how within hours of hatching, the squid is able to selectively colonize its light organ only with V. fischeri from the diverse microbial environment.
3) This selectivity is achieved through a multi-step process ("winnowing") where the squid's ciliated epithelia initially allow some bacteria to enter its light organ crypts, but then a restrictive period ensures only V. fischeri persists to form the exclusive symbiosis.
The document discusses SAS High-Performance Analytics, a product that leverages in-memory architecture through a dedicated software and hardware appliance to drive high-performance analytics. It highlights how the product addresses the entire analytical lifecycle from data exploration to model deployment to achieve insights at breakthrough speed. Key differentiators of the product include being the only in-memory offering that can develop and deploy high-end analytics models.
This document summarizes key points from a paper reviewing genomic insights into the evolution of symbiotic bacteria. The summary is:
1) Phylogenetic studies show that most bacteria that form chronic infections in animals belong to deeply branching clades that are strictly parasitic or strictly mutualistic, contradicting predictions of frequent switching between interaction types.
2) Both mutualistic and pathogenic bacterial clades are often ancient, with minimum ages inferred from host fossils indicating associations up to 300 million years old.
3) Exceptions where mutualistic and pathogenic lineages may have arisen from a common ancestor include Flavobacteria and Wolbachia, but constraints on functional capabilities still exist that prevent universal benefits to host fecundity or survival.
This document discusses how organizations can harness big data as a game changing asset. It begins by setting the context on the impact of big data and how the volume of digital information is growing exponentially. It then covers analytical layers for deriving value from big data, including the data layer, emerging trends in real analytics, and shifting the focus from hindsight to foresight. Two case studies from India are presented on applying analytics in retail and HR. Finally, it discusses how big data is changing the paradigm for analytics by enabling closer monitoring, simulation and optimization. Harnessing big data requires asking focused questions to solve specific business problems.
An exclusive presentation by Mr. Nirlap Vora, Practice Manager - Information Management - SAS Institute India Pvt. Ltd . on ‘Data Management as a Strategic Initiative.’ The presentation was made at Government Analytics & Information Summit 2013.
Este documento proporciona instrucciones para realizar varias tareas de bioinformática utilizando diferentes bases de datos como NCBI y Expasy. Incluye determinar el número de cromosomas en diferentes organismos, buscar la ubicación de genes relacionados con ciertas enfermedades, analizar una secuencia genómica específica para identificar su organismo de origen, genes y funciones, y realizar búsquedas BLAST con secuencias seleccionadas para determinar a qué organismos pertenecen.
Para determinar en qué cromosoma(s) se encuentran los genes relacionados a una enfermedad como el Parkinson, se debe identificar el número de genes presentes en la secuencia y los aminoácidos presentes en las secuencias de proteínas para encontrar similitudes con otros genes ya conocidos.
Salmonella typhimurium bacteria were grown aboard a Space Shuttle mission and compared to identical ground controls; microarray and proteomic analysis revealed that space flight altered the expression of 167 transcripts and 73 proteins in S. typhimurium, with the Hfq protein identified as a likely global regulator involved in the response; space flight samples also exhibited enhanced virulence in mice and extracellular matrix accumulation consistent with biofilm formation.
El documento proporciona información sobre el número de cromosomas de tres organismos: el perro tiene 78 cromosomas, la rata tiene 42 cromosomas y Arabidopsis tiene 10 cromosomas.
Este documento presenta una clave dicotómica para identificar 7 tipos de hongos basándose en características morfológicas como si son unicelulares, la presencia de ameroconidios, fiálides o pie basal en los conidios, el tamaño y pigmentación de la célula central y la forma cilíndrica de los conidios.
Este documento describe las deshidrogenasas, un tipo de enzima oxidorreductasa que transfieren átomos de hidrógeno entre moléculas como parte de reacciones de oxidación-reducción. Se clasifican en aerobias y anaerobias. Las deshidrogenasas juegan un papel crucial en procesos metabólicos como la glucólisis, el ciclo de Krebs y la cadena de transporte de electrones, ayudando a producir energía para la célula.
Las deshidrogenasas catalizan reacciones de óxido-reducción al transferir hidrógenos de un sustrato a una molécula aceptora como NAD+, NADP+, FAD o FMN. Están involucradas en procesos metabólicos como la glucólisis, fermentación láctica, ciclo de Krebs y cadena de transporte de electrones, donde desempeñan un papel clave en la producción de energía para la célula.
This document discusses business analytics and its strategic importance for telecommunications companies in India. It provides an overview of Idea Cellular, the challenges facing Indian telcos, and how Idea is using data analytics and customer lifecycle management. Specifically:
1) Idea Cellular is the 3rd largest mobile operator in India that uses data analytics to gain insights into customers, competition, campaigns and more.
2) Indian telcos face challenges like low ARPUs, regulatory issues, and spectrum scarcity that increase costs.
3) Idea uses advanced analytics to segment customers, create targeted campaigns, and optimize the customer lifecycle to increase revenue, retention and ARPU. Their approach has provided $100 million in revenue upl
The document provides an overview of IBM's big data and analytics capabilities. It discusses what big data is, the characteristics of big data including volume, velocity, variety and veracity. It then covers IBM's big data platform which includes products like InfoSphere Data Explorer, InfoSphere BigInsights, IBM PureData Systems and InfoSphere Streams. Example use cases of big data are also presented.
Fish presence in ponds indirectly facilitates plant reproduction across ecosystem boundaries through a trophic cascade. Fish reduce larval and adult dragonfly abundances near ponds by preying on dragonfly larvae. Fewer adult dragonflies near ponds with fish means less predation on insect pollinators. As a result, pollinators visit plants near ponds with fish more often and the plants are less pollen limited, experiencing greater reproductive success compared to plants near fish-free ponds. The study found evidence of this cross-ecosystem trophic cascade linking aquatic and terrestrial habitats.
Abstract ─ The soil-litter system is the natural habitat for a wide variety of organisms, microorganisms and invertebrates, with differences in size and metabolism, which are responsible for numerous functions. The soil mesofauna is composed of animals of body diameter between 100 μm and 2 mm, consisting of the groups Araneida, Acari, Collembola, Hymenoptera, Diptera, Protura, Diplura, Symphyla, Enchytraeidae (Oligochaeta), Isoptera, Chilopoda, Diplopoda and Mollusca. These animals, extremely dependent on humidity, move in the pores of the soil and at the interface between the litter and the soil. The edaphic fauna, besides having a great functional diversity, presents a rich diversity of species. As a result, these organisms affect the physical, chemical and, consequently, the biological factors of the soil. Therefore, the edaphic fauna and its activities are of extreme importance so that the soil is fertile and can vigorously support the vegetation found there, being spontaneous or cultivated. The composition, distribution and density of the edaphic acarofauna varies according to the soil depth, mites size, location and the season of the year. Edaphic mites are generally found in greater quantities in the organic matter layer than in the soil mineral. The subclass Acari is divided in seven orders being the Mesostigmata, Trombidiformes, Endeostigmata and Sarcoptiformes those that frequently occur in the soil. In the order Sarcoptiformes the suborder Oribatida (formerly Cryptostigmata) is one of the more numerous groups of soil arthropods, both in number of species and specimens. Considering the above facts, it was the objective of this work to know the acarofauna of the soil in a coffee plantation and rank the taxa in a decreasing way, by the use of faunistic analysis. The soil samples were taken in coffee plantation in the Experimental Station of EPAMIG, in São Sebastião do Paraíso, MG, Brazil, in two periods, end of dry and end of rainy season of the year 2013, and the extraction of edaphic mites of the soil mesofauna was done at the Laboratory of Acarology of EPAMIG Sul/EcoCentro, in Lavras, as well as other activities related to the study. The result show that edaphic mites of the cohort Astigmatina and suborder Oribatid are dominant in both periods studied, and can be worked to be an indicative of soil quality.
Species diversity and functional groups of ants (Hymenoptera: Formicidae) in ...Innspub Net
Ants play a vital role in various ecological processes in the ecosystem. They are involved in nutrient cycling, soil aeration, seed dispersal, and indicator of habitat condition. The study was conducted to determine the species diversity and functional group composition of ants near the residential area and agro-ecosystem of Mt. Agad-agad, Brgy. Puga-an, Iligan City, Philippines. Ants were collected using baits and hand collecting to sample ants. A total of 4,047 individuals belonging to four subfamilies, 17 genera, and 23 species were documented in the two sampling sites. Species diversity was recorded highest in agro-ecosystem with H’=2.74 and species richness of 3.96. Also, five invasive species, including Paratrechina longicornis was recorded in both sampling sites. The most abundant functional group was Generalized Myrmicinae (36%) near the residential area, while Subordinate Camponotini (29%) in Agro-ecosystem. The result suggests that existing land-use influences species and functional group composition of ants, and the presence of invasive species indicates the magnitude of anthropogenic disturbances in the area.
A Contribution to the Vesicular Arbuscular Mycorrhizal Fungal status on twent...iosrjce
IOSR Journal of Environmental Science, Toxicology and Food Technology (IOSR-JESTFT) multidisciplinary peer-reviewed Journal with reputable academics and experts as board member. IOSR-JESTFT is designed for the prompt publication of peer-reviewed articles in all areas of subject. The journal articles will be accessed freely online.
Wheat stem sawflies are a major pest for wheat crops, causing over $350 million in damage annually. They lay eggs inside wheat stems, where the larvae feed and cut the stems. Native parasitoid wasps that feed on sawfly larvae can help reduce damage. This study explores using diverse plantings of native wildflowers along wheat field edges to increase parasitoid populations and lifespan through providing nectar, which could help decrease sawfly infestation. Results showed higher sawfly infestation near fallow fields, parasitoids living longer with nectar access, and lower infestation correlated with higher plant diversity along edges.
This project proposal investigates indirect interactions between two species of leaf-mining moths, Phyllonorycter dubitella and P. salicicolella, that share a parasitoid wasp predator, Achrysocharoides zwoelferi. The researcher hypothesizes that P. dubitella is rare due to apparent competition with the more common P. salicicolella, mediated by their shared predator A. zwoelferi. An experiment will be conducted removing P. salicicolella from some trees to test if P. dubitella populations increase when this competitor is absent, due to a decrease in the shared parasitoid. Fifty willow
This document summarizes a study that examines the effects of invasive riparian plant species on macroinvertebrate populations in cold water streams. The researchers hypothesize that reaches with invasive species will have higher pollution tolerance scores and lower macroinvertebrate diversity than restored reaches. Samples will be taken from one degraded reach dominated by invasive buckthorn and garlic mustard, and one restored reach. Macroinvertebrates will be identified and riparian plant biomass will be estimated to determine impacts on aquatic communities.
The roots of saltmarsh plants collected from a marsh behind the Gulf Coast Research Laboratory were found to be colonized with arbuscular mycorrhizal fungi, whereas plants from other coastal locations were not colonized. This suggests that the marsh behind the lab may be low in nutrients, requiring the symbiotic relationship with fungi for improved nutrient uptake, while other areas along the shoreline have higher nutrient levels. Further study of sediment nutrients is needed to confirm this hypothesis. Microscopic examination revealed the presence of mycorrhizal fungi in stained root samples, while uncolonized roots remained unstained.
This study evaluated the effects of the slug repellent nemaslug on three common garden invertebrate species: slugs, snails, and earthworms. Specimens of each species were collected and divided into tanks, with half receiving nemaslug treatment and half serving as controls. The specimens were observed over time, and any deaths or changes in weight were recorded. Nemaslug only caused mortality in slugs and did not significantly impact the weight of earthworms. While nemaslug is effective against slugs as intended, the study found that snail populations actually increased the most with nemaslug application. As earthworms are generally beneficial to soil health, the
This document reviews the potential for using spiders as biological control agents of mosquitoes. It discusses how spiders have a wide insect prey range and can act as natural predators of mosquitoes. Certain spider species have been shown to specialize in preying on mosquitoes. The document reviews research on the mosquito-eating behaviors of spider species like Evarcha culicivora from East Africa and Paracyrba wanlessi from Southeast Asia. It discusses how these spiders use vision and olfaction to target mosquitoes that have recently fed on blood, helping to control disease-transmitting mosquito populations. The review concludes that further understanding predator-prey relationships between spiders and mosquitoes could help develop biological control programs utilizing
The pattern of field infestation by the flea beetles, Podagrica spp., was assessed in okra-kenaf intercrop system with a view to determining a cropping pattern that would assist in controlling the pest problem. Okra and kenaf were intercropped in row combinations of 1:1, 1:2, 2:1 and 2:2 while sole-cropped okra and kenaf served for comparison. Field sampling for flea beetles commenced three weeks after planting and it lasted till the 12th week, a period that extended to the postharvest stage of okra. There was a significant difference (P Ë‚ 0.01) between the population of the two Podagrica spp. (with P. uniforma being more abundant than P. sjostedti) and among the six planting patterns. The pest population also differed (P Ë‚ 0.05) between the two crops and among (P Ë‚ 0.001) the vegetative, reproductive and postharvest stages of okra. Sole kenaf had a significantly higher level of infestation by the flea beetles followed by sole okra and two rows of okra intercropped with one row of kenaf in descending order. All the other three intercrop patterns had a significantly lower infestation level. Kenaf attracted more flea beetles than okra at the vegetative stage while stumps of okra left in the field after harvesting was over sustained a significantly higher population of flea beetles. Obtained results showed that intercropping could be used, especially by poor rural farmers, as a pest control strategy against Podagrica spp. Due to the considerable population of flea beetles sustained by okra stumps, farmers should be encouraged to get rid of leftovers after harvesting as a way of further controlling Podagrica spp. The combination of intercropping and farm sanitation would assist in reducing reliance on synthetic chemical insecticides.
Ecology of plant parasitic nematode’s (PPN's)Francis Matu
This document provides an overview of the ecology of plant-parasitic nematodes (PPNs). It defines key ecological concepts and describes various aspects of PPN ecology, including population ecology, community and ecosystem interactions, the soil food web, physical habitat factors, foraging patterns, niche partitioning, and the role of PPNs in ecosystem functions like primary productivity, decomposition, and nutrient cycling.
Ecological interactions form the backbone of an ecosystem. It helps in maintaining the
dynamic equilibrium of an ecosystem. All organisms are linked to at least one other species in a
variety of critical ways, for example, as predators or prey, or as pollinators or seed dispersers with the
result that each species is embedded in a complex network of interactions. Consequently, the
extinction of one species can lead to a cascade of secondary extinctions in ecological networks.
Moreover, interactions between species can lead to ‘community closure’ after the loss of a species,
with the result that a locally extinct species cannot re-establish itself if it is reintroduced. Many
ecological interactions involve flagship species and keystone species as in the case of Macaca
silenus & Cullenia exarillata. Then some interactions like mycorrhiza help in nitrogen fixation.
Strategies like predation reduce the loss of vegetation through grazing. Interaction can be either intraspecific or interspecific. Interactions between individuals of the same species
and those between individuals of different species are called intra- & interspecific interactions.
respectively. The lichen serves as an example of interspecific interaction and dog fighting.
for a common prey for intraspecific interaction.
This document discusses ants and their taxonomy, morphology, and ecological importance. It begins with an overview of ant taxonomy, describing their kingdom, phylum, class, order, and some major species. It then discusses the different castes found in ant colonies - queens, males, and workers. The document outlines various ways ants are ecologically important, including as predators, in seed dispersal, soil bioturbation, and pathogen suppression. It also presents two case studies on ants' effects on controlling plant pathogens and impacting soil nutrients and plant growth. In conclusion, the document emphasizes ants' roles in ecosystem functioning and nutrient cycling.
GOOD COPY individual paper, St. Andrews Field CourseRachel Brodie
This document summarizes an experiment that examined the effects of predator interactions between green crabs and dogwhelks on the consumption of blue mussel prey. The experiment tested single-predator treatments of just dogwhelks or just crabs, as well as a multiple-predator treatment with both species present. Results showed that dogwhelk feeding rates decreased significantly in the presence of green crabs, while crab foraging increased when dogwhelks were present. Additionally, significantly more total mussels were consumed in the multiple-predator treatment than in the single-predator treatments. This indicates that the presence of another predator species impacts the feeding behavior and rates of these invertebrate predators.
Biotic factors with reference to mutualism, amensalism, commensalism and para...Mariyam Nazeer Agha
This document discusses different types of biological interactions between species: mutualism, amensalism, commensalism, and parasitism. It provides examples for each type of interaction. Mutualism benefits both species, such as the relationship between plants and mycorrhizal fungi. Amensalism harms one species without affecting the other, like competition between trees and saplings. Commensalism benefits one species without affecting the other, exemplified by phoretic mites on insects. Parasitism benefits one species at the expense of the other, illustrated by tapeworms living in mammalian guts.
The document discusses invasive alien species (IAS) as a threat to biodiversity and the environment. It describes how some species have traits like rapid growth and reproduction that allow them to outcompete native species. IAS are often introduced through human activities like importing plants, releasing ballast water from ships, or the pet trade. They can negatively impact ecosystems, economies, agriculture, and human health. Effective control requires integrated approaches like mechanical removal, chemicals, biological controls, and habitat management. The conclusion states that IAS are a major threat globally and that their impacts must be managed.
2. Table 1. Snail grazing intensity on green leaves of salt marsh were designed to elucidate potential causal processes underlying
cordgrass in southeast salt marshes those patterns.
Radulations,
State cm per stem Effects of Snail Grazing Activities on Fungal Biomass. To test the
hypothesis that snails facilitate fungal invasion through grazing
Delaware 8.6 1.8 activities, we measured the effects of snail presence and simu-
Maryland 10.3 1.4 lated snail grazing (i.e., razorblade cuts) on fungal growth in
Virginia 16.7 2.3 green Spartina leaves in a 2-month caging experiment. In Feb-
North Carolina 12.8 1.6 ruary 2001, before snails began to graze live marsh grass (20, 21),
South Carolina 9.3 2.8 in the intermediate height-form Spartina zone, we established
Georgia 28.3 2.3 replicated (n 6) 1-m2 galvanized mesh cages (20) assigned to
Florida 13.6 3.5 the following treatments: control ( 220 snails per m2), snail
Louisiana 9.8 2.7 removal, and snail removal plus simulated grazing. We simulated
Data are means SE and represent pooled data from two marshes in each snail grazing on uninjured green Spartina by using razorblades to
state. make longitudinal cuts that went all of the way through the
leaves. Every week, the average total length of radulations per
stem in the control snail treatments was quantified. We then
from each sample, all fecal pellets were removed, and, because replicated those radulation distributions (i.e., the same average
of logistical constraints (i.e., the constraint of having to use short number of radulations) on all stems in simulated grazing treat-
leaf sections with available lab equipment combined with the ments. After 2 months, we measured fungal biomass on respec-
difficulty of detecting ergosterol concentrations in small sam- tive green leaf types (uninjured, radulated, and simulated scar)
ples), four sections of each leaf type, uninjured or radulated, from each treatment (n 2 leaves per leaf type per replicate) by
were pooled for analysis (n 4 per treatment). We also using the ergosterol methods described above (23). We randomly
quantified fecal pellet density on 10-cm-long midleaf sections of pooled the two leaves from each of our six replicates into three
300 uninjured and 300 radulated green leaves sampled from groups of four leaves each for analysis because of logistical
independent stems. We counted pellets on the 10-cm-long constraints (see above) of the ergosterol extraction technique.
radulations themselves, not on green tissue surrounding the area For statistical analysis, then, n 3 per treatment. Snail densities
(see Fig. 1B). On undamaged leaves, we counted fecal pellets on were monitored weekly (20).
similarly sized and oriented areas. We counted fecal pellets on To test the hypothesis that snail deposition of fecal pellets on
the first 300 leaves of each leaf type we encountered while exposed wounds stimulates fungal growth, we added fecal pellets
walking a 1,000-m transect through the short-form Spartina zone. to artificially induced wounds on green Spartina leaves in a
We conducted this survey at night during ebb and flood tides, 2-week field experiment. In May 2001, in an intermediate
when snails are most actively grazing (17). These field surveys height-form Spartina zone naturally devoid of snails, we applied
(i.e., fungal biomass in radulations and fecal pellet counts) were the following treatments (n 6) to 1-m2, staked areas: simulated
conducted to establish initial patterns of interactions between snail grazing and simulated snail grazing plus fecal pellets. We
fungi and snail grazing activities. The following experiments simulated natural snail grazing intensity (17–19) by cutting 10-cm
Fig. 1. (A) Snail fecal pellets at high density ( 40 pellets; average densities were found to be 22.75 pellets per 10 cm of radulation; see Results) concentrated
on a snail-induced wound on a live Spartina leaf. Note the fungal concentration (dark area) along the radulation edges. A leaf with fecal pellets was collected
at night and photographed the next morning. (B) Littoraria on a Spartina leaf grazing a radulation. The majority ( 80%) of snail-induced wounds on cordgrass
extend through the leaf, as is the case in this picture.
15644 www.pnas.org cgi doi 10.1073 pnas.2535227100 Silliman and Newell
3. longitudinal wounds on three green leaves on one-third of the
stems in each plot. Fecal pellets were collected from a snail-
holding container in an outside flow tank that housed snails,
fresh Spartina stems (changed every 3 days), and seawater and
were applied directly on simulated grazer scars (very similar in
appearance to the radulation in Fig. 1B) at a rate of 22 pellets
per scar per day, a natural deposition rate as determined by our
field survey (see Results). After 2 weeks, we measured fungal
biomass on artificially injured leaves from each treatment (n
4 leaves per replicate) by using methods described above (23).
We randomly pooled replicates into pairs for analysis because of
logistical constraints (n 3 per treatment).
Effects of Fungus Production on Snail Growth. To test the prediction
that the extent of fungal biomass in a green-leaf food source
positively affects snail growth, substrate-specific growth rates for
juvenile snails (shell height 3 mm) were determined for three
food items: unwounded green leaves, green leaves with radula-
tions, and green leaves with 10-cm long, 1- to 2-month-old
razorblade cuts. Leaves were collected from Spartina plants
housed in mesh cages in the marsh at equal tidal elevations (see
above) and exposed to the following treatments (n 6): control
snails ( 220 individuals per m2), snail removal, and snail re-
moval plus simulated grazing. We used this experimental design
to control as much as possible for potential differences in plant
ECOLOGY
quality other than fungal content [e.g., differential flooding Fig. 2. (A and B) Fungal abundance [ g of ergosterol (erg.) per cm2 of leaf
frequencies leading to differences in plant nitrogen content blade] in naturally occurring uninjured and radulated green Spartina leaves
(21)]. Snails were housed in 473-ml glass jars in the laboratory. (A) and experimentally generated uninjured (snail removal treatments), snail-
Each treatment had 16 replicates. Each jar housed four juvenile grazed (control snail treatments), and razor-cut (simulated snail grazing
treatments) green leaves (B). (C) Juvenile snail growth rates on each experi-
snails and four, 20-cm-long leaf segments of the designated food
mentally generated green leaf type. Different letters denote significant pair-
item. Seawater (60 mm) was added to each jar to maintain a wise differences at P 0.05 in mean values as determined from Tukey’s post
hydrated environment for both plants and snails, and leaves and hoc test. Error bars represent SE.
water were changed every 4 days to ensure treatment integrity.
Change in shell length was measured after 5 months. We used
mean change in shell length in each replicate as a single datum densities were monitored as described above. After 4 months, we
per replicate. quantified aboveground plant biomass in a 25-cm2 quadrat by
using destructive techniques (20) and recorded the total length
Mechanisms of Top-Down Control. To test the hypothesis that of radulations on 15 randomly selected plants (20). We also
facilitation of microbial invasion is a primary mechanism by measured fungal biomass on green leaf types from each treat-
which snails control Spartina growth (i.e., fungal invasion in ment (n 4 leaves per replicate) by using methods described
snail-induced wounds, and not the wounds themselves, are the above (23). We randomly pooled replicates into pairs for analysis
primary cause of decreased growth), we experimentally sepa- because of logistical constraints (n 3 per treatment).
rated the negative effects of snail consumption and fungal
invasion on marsh grass growth by using fungal removal tech- Statistics. Treatment differences were assessed by using one- and
niques (i.e., application of fungicide). In the intermediate-form two-way ANOVA followed by Tukey’s post hoc test. Data either
Spartina zone, we established replicated (n 6) 1-m2 cages exhibited homogeneity of variance and were normally distrib-
assigned to the following treatments: snail exclusion, snail ex- uted or were log transformed to meet ANOVA assumptions.
clusion plus fungal removal, control snails ( 220 individuals per Transformations produced data that met ANOVA assumptions.
m2), and control snails plus fungal removal. To exclude fungi
from plant tissue, we sprayed Spartina stems in fungal removal Results
treatments once every 5 days with the systemic fungicide Daconil
Patterns in Snail Grazing. Extensive survey of southeast and
Ultrex Turf Care with Chlorothanlo (Zeneca, Wilmington, DE).
gulf coast salt marshes showed that wound-grazing by snails is wide-
This fungicide seemed ideal for marsh use, because plants take
it up within 2 h and it is an effective killer of terrestrial fungi (G. spread throughout its range (Table 1). Analysis of Spartina leaves
Gilbert, University of California, Santa Cruz, personal commu- collected from our initial marsh survey in Georgia revealed that
nication) taxonomically similar to the dominant marsh fungi mean fungal biomass was significantly higher on radulated green
Phaeosphaeria and Mycosphaerella, which are typically 90% of leaves compared with uninjured green leaves (Fig. 2A). Fungal
marsh fungal biomass (22). Preliminary marsh experiments biomass was 15-fold higher on leaves with snail-induced wounds,
showed that Daconil application does not affect growth of and nearly undetectable on green leaves (Fig. 2 A). Our initial
uninjured Spartina plants (see Fig. 4C) or Littoraria grazing marsh survey in Georgia also showed that mean density of snail
preferences (when offered a choice between leaves with and fecal pellets was 4-fold greater on wounds on radulated green
without Daconil; 2.4- 0.7-cm radulations per leaf for nonfun- leaves compared with uninjured green plant surfaces (P 0.01,
gicide treatments; 3.1- 1.1-cm radulations per leaf for fungi- paired t test; pellets per radulation 22.75 6.45; pellets per green
cide treatments; P 0.30, paired t test). Daconil was sprayed for leaf surface 5.41 4.35).
30 seconds on each plot during a rainless day at low tide, when
snails are inactive for at least 6 h, and water was similarly sprayed Effects of Snail Grazing Activities on Fungal Biomass. Removal of
on nonfungicide treatments as a disturbance control. Snail- snails from the marsh reduced fungal biomass on green leaves to
grazing was simulated, the cages were constructed, and the snail low levels (Fig. 2B). In contrast, snail removal plus simulated
Silliman and Newell PNAS December 23, 2003 vol. 100 no. 26 15645
4. Fig. 3. Response of fungal growth [ g of ergosterol (erg.) per cm2 of leaf
blade] to snail fecal pellet addition on simulated grazing scars on green
Spartina leaves. Error bars represent SE. *, P 0.05, paired t test.
snail grazing significantly facilitated fungal invasion, because
fungal biomass increased 21-fold relative to removals and 76%
relative to control snail treatments. Grazing by control snails
produced fungal growth on green leaves markedly similar to that
on radulated green leaves collected in the survey (Fig. 2) but
lower than simulated grazing scars. This difference in fungal
biomass likely occurred because snails are cropping fungi at the
same time they are facilitating it, unlike simulated grazing
treatments, which only facilitate fungal growth. Field experi-
ments indicated snails further enhance fungal growth through
deposition of feces. Addition of fecal pellets at natural deposi- Fig. 4. Interactive and separate effects of snail presence and fungicide on the
tion rates to simulated grazer scars on green leaves increased total length of grazer-induced wounds per stem (A), fungal biomass [ g of
fungal biomass by 171% (Fig. 3). ergosterol (erg.) per cm2 of leaf blade] on green leaves (B), and Spartina
aboveground biomass (C). Different letters denote significant pairwise differ-
Effects of Fungus Production on Snail Growth. Snail growth rates ences at P 0.05 in mean values as determined from Tukey’s post hoc test.
mirrored fungal availability on each leaf type: Mean growth rates Error bars represent SE.
were greatest on razor-cut leaves, less on radulated, and least on
green leaves (Fig. 2C). Snail growth on green leaves, like fungal
availability, was negligible, and 48% of juveniles in uninjured, removals where fungal invasion was not facilitated but increased
green-leaf treatments died ( 3% for other treatments). Spartina growth in treatments where snail grazing promoted
invasion (Fig. 4 B and C).
Mechanisms of Top-Down Control. Survey of Spartina stems in the
Discussion
fungicide snail experiment revealed that snail presence re-
sulted in substantial scarring of green leaves and that grazing Fungal Farming in Ants, Beetles, Termites, and Snails. Evolutionary
intensity depended on fungicide (Fig. 4A). With fungicide ap- biologists have recently suggested that fungus-growing animals,
plication, the total length of radulations per stem increased by like human agriculturists (26), use a range of cultivation strat-
29% (Fig. 4A), a pattern possibly indicating snails compensate egies, varying from ‘‘low-’’ to ‘‘high-level food production’’ (27).
for decreased fungal availability with intensified grazing. Low-level promotion of fungal growth includes cases where
Analysis of Spartina leaves confirmed our initial findings animals modify local ecosystems to encourage or protect fungal
that snail grazing facilitates fungal invasion: Fungal biomass growth, provide substrate to promote growth, and consume the
was negligible on green leaves in snail removal treatments but cultivated fungi (27). At the other extreme, in high-level fungus
high in treatments with Littoraria (Fig. 4B). Snails differen- cultivation, animals additionally vertically transmit cultivar in-
tially affected fungal biomass depending on the presence ocula, inoculate substrate with propagules, fertilize the crop,
absence of fungicide. In nonfungicide treatments, snail grazing employ physical and or chemical means to exclude competitors
increased fungal biomass by 17-fold, whereas in fungicide and pathogens, and harvest and consume the cultivated
treatments this facilitative effect was dampened markedly fungi (27).
( 4-fold). The effect of fungicide application on the fungal In terrestrial systems, instances of high-level fungal cultivation
biomass on green leaves depended on snail level, as fungicide have been extensively documented and studied (1–11, 27).
had no significant effect in snail removals where fungal Fungus-growing attine ants and termites, for example, exhibit
invasion was not facilitated but strongly suppressed (71%) high-level food production (1, 4). Their farming strategies in-
fungal growth in treatments where snail grazing promoted clude evolved mechanisms of cultivar transmission from one
invasion (Fig. 4B). parent to offspring, preparation of substrate, collection and
Coincident with fungal invasion of grazer-induced wounds on concentration of growth medium, inoculation with propagules,
live Spartina were dramatic decreases in plant growth (Fig. 4C). fertilization of crop with fecal material or oral exudates, chemical
The magnitude of this top-down effect, however, like fungal and physical weeding, and harvesting and consumption of fungi.
biomass, depended on fungicide level, because snails exhibited Many beetle species also farm fungi, but do so in bored-out holes
relatively less control of Spartina in plots with fungicide (Fig. in live trees, where cultivated hyphae provide food for adults and
4C). In nonfungicide treatments, snail grazing reduced standing developing pupae (12, 13). Many of their fungal production
biomass by 65% relative to removals, whereas in fungicide strategies also fit the high-level category. Examples of low-level
addition plots, grazing by Littoraria decreased growth by only fungal production have not been experimentally demonstrated
31% (Fig. 4C). The effect of fungicide on Spartina biomass (27), although evolution of this strategy could be common, given
depended on snail presence; fungicide had no effect in snail its relative engineering simplicity.
15646 www.pnas.org cgi doi 10.1073 pnas.2535227100 Silliman and Newell
5. We argue that our experimental and large-scale survey prepared substrate to initiate fungal growth, weed their crops, or
results reveal a low-level, facultative farming mutualism§ obligately rely on one fungal species for farming. If there is an
between the marine snail Littoraria irrorata and intertidal important message to be learned from Littoraria’s distinct lower-
marsh fungi that may occur over the entire extent of Littorar- level fungal production strategy, it may be that evolutionary
ia’s 2,000-km range (Table 1 and refs. 19 –21). When grazing success of fungal farmers may not depend on intricate pest
live marsh grass, Littoraria create and maintain wounds on leaf management and inoculation techniques as long as cultivated
blades with their radulae, and the opening of live plant tissue fungi naturally occur and are successful even without farmer’s
results in microbial invasion, significantly increasing availabil- care (i.e., fungi are effective dispersers and have strong pathogen
ity of their preferred food (16, 17), leaf material containing and competitor resistance).
ascomycete fungi. Simulation of snail grazing demonstrates
that the simple mechanical opening of grass tissue is ample Is Fungal Farming Common but Overlooked? This study demonstrates
engineering to promote invasion and growth of marine fungi fungus-growing behavior in the marine environment and outside
(Fig. 2), whose spores are ubiquitous across the marsh surface the class Insecta. However, given the relative engineering simplicity
(22). Seeding and or propagule transplantation is therefore of low-level fungal production, the benefits of having predictable
not necessary for snail promotion of fungal growth. Nonethe- food supply and the fact that many detritivores have been shown to
less, our field experiments and night-time marsh survey stimulate secondary respiration through foraging activities (refs. 16
showed that snails concentrate deposition of nitrogen- and and 17 and references therein), fungal farming on live, senescing,
hyphae-rich fecal pellets¶ on radulations and that this activity and or dead plants may be more geographically and phylogeneti-
enhances fungal growth. Potential mechanisms of fungal cally widespread than presently envisioned, especially in systems
growth-enhancement by means of pellet deposition include where fungal spores are abundant, grazers can manipulate fungus-
fertilization [growth of marsh fungi is limited by nitrogen (23)] growing media, and fungus is a major diet component of consum-
and or propagule enhancement (it remains to be determined ers. Many grasses and grass-like macrophytes other than Spartina
whether undigested mycelia in fecal pellets are viable). Lab- exhibit standing decaying shoots (i.e., senescing live leaves invaded
oratory studies indicate snail success is intrinsically linked to by fungi) in both marine and freshwater ecosystems (23), and these
ECOLOGY
fungal availability in green Spartina leaves, because the growth plant communities may very well meet the criteria for potentially
of juveniles increased with increasing fungal biomass. Most harboring fungal farmers (high fungal production and mycopha-
revealing was that juvenile snails did not grow and experienced gous and shredding invertebrates).
48% mortality when fed uninjured, green leaves, a finding
consistent with controlled lab experiments (28), showing that Top-Down Control of Aquatic Plants by Means of the Facilitation of
snails can grow only on fungus-colonized Spartina or pure Fungal Invasion. If animals farm fungi on live or senescing plants
mycelium and not on sterile leaves or ones colonized by in other aquatic systems, both fungi and grazers may evolve in the
bacteria. These growth-study results indicate that Littoraria same direction, one that favors fungal growth at the expense of
obligately employs fungus-promoting feeding strategies to the invaded host. In terrestrial systems, it is well established that
benefit from grazing live Spartina. In other words, the primary the impact of insect fungal farming can be devastating to plants
purpose of grazing live grass is likely not feeding, but prepa- used as growth media (1–13, 16). For example, fungus-farming
ration of substrate for growth of nutritious fungi and con- activities by beetles in bored-out holes of tree trunks can cause
sumption of facilitated invasive fungi. massive die-off of forests, because facilitated, pathogenic fungi
Together, these experimental findings reveal that Littoraria pro- seriously damage their hosts (6, 12–13). Likewise, snail radular
motes fungal growth on live Spartina through a combination of activities promote growth of fungi on green Spartina leaves, and
relatively nonnutritive grazing (Fig. 2 and ref. 28) and fecal pellet our fungal removal experiments demonstrate that this invasion
deposition, and that this fungal production has a positive effect on can account for at least 60% of the negative effects of snail
snail growth. In turn, fungi benefit from wound-grazing by gaining grazing on marsh grass growth [probably more because fungicide
access to inner plant tissues and by receiving supplements from was not completely effective in suppressing fungal growth (Fig.
snail feces. Littoraria thus employs a low-level food production 4)]. Snail farming activities thus favor fungal growth at great
strategy whereby it prepares a favorable environment for fungal expense to the infected host plant [i.e., snail grazing activities
growth, provides substrate to promote growth, adds supplemental commonly reduce marsh plant growth 40–100% (19–21)]. These
nutrients and or propagules, and consumes fungus. results, combined with the finding that snails consume small
Unlike ants and termites, snails do not seem to inoculate amounts of live plant tissue when wound-grazing (20), show that
snails exert control of marine plant production by facilitating
growth-suppressing fungi and that this top-down effect is dis-
§Strictcriteria for ‘‘low,’’ ‘‘medium,’’ and ‘‘high’’ levels of fungal farming have not been proportionate to grazer consumption capabilities. This study
established and have only recently been suggested (27). Although we argue that snail demonstrates top-down control by means of the facilitation of
fungus-growing behavior represents low-level farming, this could be revised based on fungal invasion in a marine system; however, if grazer promotion
future results. Our findings are relatively silent as to whether growth-promotional effects
of snails are adaptations or mere by-products. If they are by-products, then this snail– of fungal invasion is not limited to salt marshes (as suggested
fungus interaction may be more accurately classified as protofarming behavior. In addi- above), then mesograzers could be exerting similarly strong but
tion, because we have no evidence that either fungus or snails have undergone selection undetected control over primary production and community
for participation in this interaction and both organisms survive independent of the
structure in many other aquatic systems.
relationship, we have classified this positive interaction as a facultative mutualism.
¶We did not determine whether snails purposefully deposited fecal pellets on grazer-
We thank Sarah Lee, Ryan Harlick, and Tracy Buck for their dedicated
induced wounds or, rather, that pellets were simply concentrated on wounds because of
increased time spent by snails feeding in those areas. If the former is found to be true, then
work and C. Layman, M. Bertness, U. Mueller, T. Schultz, R. Paine,
a stronger case for higher-level fungal cultivation [given its current definition (27)] can be and two anonymous reviewers for their comments on the manuscript,
made, because snail behavior would then seem to have evolved for ‘‘planting’’ or including the suggestion of the word ‘‘protofarming’’ by one anony-
‘‘manuring’’ by means of feces. mous reviewer. This work was supported by the National Science
Foundation (Dissertation Improvement Grant and Biological Ocean-
Mechanisms of growth enhancement are not exactly known, but nutrient transfer from
fecal pellets is likely, given that snail pellets are high in nitrogen content and fungal
ography), the Environmental Protection Agency (Science to Achieve
growth on cordgrass is nitrogen-limited (17, 18, 22, 23). Pellets could additionally provide Results Fellowship), and the National Oceanic and Atmospheric
fungal propagule supplements, given that 50% of mycelium in snail feces typically remains Association (National Estuarine Research Reserve System) Narra-
undigested and intact (25). gansett Bay Fellowship.
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