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Selectiveforagingby EasternRed-backedSalamanders, Plethodon cinereus,among3ant species;
Aphaenogasterpicea,Lasiusalienus...
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Abstract
Eastern Red-backed Salamanders, Plethodon cinereus, are one of the most abundant
organisms within the United St...
3
Introduction
One of the most widely distributed and commonly observed amphibian species in the
Eastern United States is ...
4
Red-backed salamanders are generalist predators with ants being an important part of
their diet, making up 33% of prey t...
5
occurred in only 2% of diet samples with ants (Anthony and Pfingsten, 2013). The hypothesis is
that P. cinereus would pr...
6
Paluh et al (under review) found that striped P. cinereus consumed 2.5 times more ants than
unstriped P. cinereus. Becau...
7
Every feeding trial was ran for a duration of 1 hour. The hour feeding duration was
initiated once an individual P. cine...
8
within 15 minutes. Individuals who did not attack within the first 15 minutes were considered to
be “unresponsive” (Jaeg...
9
and L. alienus, was a fatty acid with a retention time of about 15 minutes (Figures 5 & 6). The
GC-MS analysis indicated...
10
species, L. nearticus, as well especially given that they have small colonies that would be less
able to mount a defens...
11
Skelhorn and Rowe, 2006; Wiklund and Jarvi 1982). Through taste-rejection a predator is able
to determine, either throu...
12
seconds) was observed in L. alienus. This may indicate that P. cinereus prefers to forage on L.
alienus more so than A....
13
cinereus exhibited that the use of chemical cues through vomernasal sensory is an important
adaptation for detecting pr...
14
Literature Cited
Alder, K., 1969. Extraoptic phase shifting of circadian locomotor rhythm in salamanders.
Science 164:1...
15
Halpern, M., 1987. The organization and function of the vomeronasal system. Ann. Bev.
Neurosci. 10:325-362.
Hölldobler,...
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cinereus) under various lighting conditions. Journal of Herpetology 35521-524.
Placyk, J.S. and Graves, B.M., 2002. Pre...
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FIGURE LEGENDS
Figure 1: Latency in seconds to first attack on ant species Aphaenogaster picea as a function of
Aphaeno...
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retention time of 15 minutes indicates fatty acids as the most abundant chemical compound
within L. alienus. This sampl...
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0 100 200 300 400 500 600 700 800 900 1000
NumberofAphaeanogasterpiceaeaten
Latency(seconds)to firs...
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0 100 200 300 400 500 600 700 800 900 1000
NumberofLasiusalienuseaten
Latency (seconds) to fista...
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0 100 200 300 400 500 600 700 800 900 1000
NumberofLasiusnearticuseaten
Latency (seconds) to firstattack
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Apeanogaster picea Lasius alienus Lasius nearcticus
Mean number of ants eaten Times attacked by a...
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Spies - Selective foraging by Eastern Red-backed Salamanders (Plethodon cinereus) between 3 ant species; Aphaenogaster picea, Lasius alienus, and Lasius nearticus

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Spies - Selective foraging by Eastern Red-backed Salamanders (Plethodon cinereus) between 3 ant species; Aphaenogaster picea, Lasius alienus, and Lasius nearticus

  1. 1. 1 Selectiveforagingby EasternRed-backedSalamanders, Plethodon cinereus,among3ant species; Aphaenogasterpicea,Lasiusalienus,andLasiusnearticus. NICOLASA.SPIES,SARAHBOLTON,and KYLE HOVEY Departmentof Biology,John CarrollUniversity,University Heights,Ohio,44118 RunningHead:SPIES ET AL: SELECTIVEFORAGINGBY RED-BACKEDSALAMANDERS
  2. 2. 2 Abstract Eastern Red-backed Salamanders, Plethodon cinereus, are one of the most abundant organisms within the United States; because of this, many studies have been conducted on their behavior, foraging tactics, and diet. P. cinereus has been described as a generalist predator of invertebrates available in terrestrial environments. From all these studies, only a few have managed to directly assess their dietary preferences to a species level. We examined foraging tactics on 3 different ant species; Aphaenogaster picea, Lasius alienus, and L. nearticus, to determine if P. cinereus prefers one species of ant over another within forests in northeastern Ohio. All 3 ant species inhabit similar habitats of P. cinereus, but were eaten at different rates. Our results indicate that P. cinereus forages on A. picea and L. alienus at about the same rate and avoids foraging on L. nearticus. Plethodon cinereus avoid foraging on L. nearticus due to the high abundance of volatile chemicals specifically the chemical compound, 2-tridecotone. P. cinereus most likely prefer A. picea and L. alienus because of their high caloric values and the energy they receive in return. Our results also demonstrate how salamanders rely on chemical cues through vomeronasal sensory to access prey items. Since ants are an abundant species within terrestrial environments, it is important to consider what the effects could be on forests when red-backed salamanders prefer to forage on specific ant species and avoid foraging on other ant species. More importantly this idea changes the way ecologists view tropic interactions within complex communities in terrestrial environments.
  3. 3. 3 Introduction One of the most widely distributed and commonly observed amphibian species in the Eastern United States is the red-back salamander, Plethodon cinereus (Petranka, 1998). This species is very important to food web structures in terrestrial ecosystems. According to Semiltch et al’s (2014) study they believe that previous results have underestimated the importance of salamander biomass, nutrient, and energy flux, and their functional role in regulating invertebrates and carbon retention in forest ecosystems. This species can be found under logs, leaf litter, and rocks in late successional deciduous forests of northeastern North America (Petranka, 1998) and feed on a broad variety of invertebrates (Burton, 1976). Common prey of P.cinereus are Acarina (mites), Araneida (spiders), Collembola (springtails), adult Coleoptera (beetles, primarily Curculionidae), larval Coleoptera, adult Diptera (flies), larval Diptera, formicid Hymenoptera (ants), non-formicid Hymenoptera (wasps), larval Lepidoptera(moths), shelled Gastropoda (snails) and non-shelled Gastropoda (slugs) (Maerz et al, 2006). P. cinereus forage exclusively at night (Alder, 1969, 1970) when visual cues would likely not be available for prey detection under cover objects and the dense canopy of old growth forests, so the primary detection of prey is through chemical cues (Placyk and Graves, 2001). More accurately, David and Jaeger (1981) found that P. cinereus rely on visuals cues to detect mobile prey but rely primarily on chemical cues to locate stationary prey. The olfactory system of terrestrial salamanders is characterized by an elongate snout that houses paired and cartilaginous olfactory capsules (Placyk and Graves, 2002). The nasal olfactory system is primarily responsible for the detection of volatile odorants (airborne chemical cues), while the vomeronasal system responds to primarily nonvolatile odorants (substrate-borne chemical cues) (Burghardt, 1980, Bertmar, 1981, and Halpern, 1987).
  4. 4. 4 Red-backed salamanders are generalist predators with ants being an important part of their diet, making up 33% of prey taken in northeastern Ohio (Ivanov et al, 2011). Ants are very abundant organisms in terrestrial environments, having the ability to physically and chemically alter the soil environment which in turn indirectly affects plants and other organisms inhabiting the leaf litter (Holldobler and Wilson, 1990; Folgarait, 1998). Recent studies suggest that P. cinereus exhibit selective foraging behavior within their territories and ant diversity observed in the diet represents a subset of that available in the surrounding leaf litter habitat (Paluh et al, under review). Therefore, P. cinereus preyed on a subset of the available ants present within their territories (Paluh et al, under review). Paluh (under review), indicated that in northeastern Ohio the ant species, Aphaenogaster picea, were among the most eaten ant species within P. cinereus territories, while Lasius aliens tended to be avoided. For this current study the goal is to determine if P. cinereus is a specialist on one particular ant species over another. We chose to use 3 different species of ants for this experiment that are common within leaf litter in northeastern Ohio. Two of the 3 ant species were selected from data previously collected, A. picea and L. alienus, and the third ant species selected was L. nearticus. A. picea is a very common species on the edge of woods in moist or dense woods (Wesson and Wesson Jr., 1940), L. alienus is a non parasitic ant found throughout North Temperate Zone (Regnier and Wilson 1968), and Lasius nearticus is a moderately abundant species found under stones and logs in upland woods (Wesson and Wesson Jr., 1940). Maerz et al (2005) found one introduced ant species, Lasius alienus, among seven native ant species. L. alienus was the fourth most frequent and volumetrically important ant in salamander diets, occurring in 13% of samples with ants and accounting for an average of 10% of ant volume. L. alienus was significantly more common than its native congener, L. nearticus, which
  5. 5. 5 occurred in only 2% of diet samples with ants (Anthony and Pfingsten, 2013). The hypothesis is that P. cinereus would prefer A. picea over L. alienus and L. nearticus, because of the defensive compounds found in L. alienus, which could be also present in the congener, L. nearticus. Methods Specimens collected and housing Ants were collected from the beginning of September 2014 to the beginning of November 2014 at Doan Brook Watershed, Cuyahoga County, Ohio (N 41° 27.779 W 81° 18.252) and The West Woods, Geauga County, Ohio (N 41° 29’ 0.76” W 81° 34’ 19.85”). During this time 3 different colonies of each ant species (A. picea, L. alienus, and L. nearticus) were collected from underneath cover objects (rocks, logs, etc.). When collecting ants the observations was made that the species, L. nearticus was never found under a cover object cohabitating with P. cinereus. Ants were collected using a garden shovel and then placed into plastic Ziploc containers with soil and leaf litter substrate. These ants were then housed in a temperature controlled lab room at 17 C under a natural photo period. P. cinereus were collected from the same locality as Paluh et al in April 2014. These individuals were used during the summer 2014 in a separate experiment. Salamanders were kept in the same lab room, under the same conditions. They were housed in 480 cc glass bowl containing leaf litter prior to experiment. Feeding Experiment The feeding experiment was conducted over a consecutive 3 week time span from October 25, 2014 – November 9, 2014. Twenty-four striped adult female P. cinereus (snout-vent length (SVL) of 32-34 mm) (Anthony and Pfingsten, 2013). Anthony et al (2008) indicated that unstriped P. cinereus would consume more ants as prey rather than striped P. cinereus, however,
  6. 6. 6 Paluh et al (under review) found that striped P. cinereus consumed 2.5 times more ants than unstriped P. cinereus. Because of this recent study, we chose to use the striped morph of P. cinereus in this feeding experiment. In order to control for the level of hunger at the start of each trial, a rigid feeding schedule was maintained (Jaeger and Barnard, 1981) and individual P. cinereus received ants to eat once every 7-8 days during the 3 week period. Individual P. cinereus were placed into petri dishes (65mm X 15mm) containing a lid covered with white opaque masking tape while the bottom of the petri dish lined with damp filter paper (Jaeger and Barnard, 1981). The cover lids were wrapped with white opaque masking tape to replicate the natural microhabitats of a cover object, such as a rock or log, where P. cinereus find refuge (Petranka, 1998). Salamanders were placed into these petri dishes 7 days prior to the feeding experiment allowing the substrate to be marked with their own pheromones so they would exhibit little escape behavior (Tristram, 1977). During the first week trial, 8 individual P. cinereus were fed A. picea, 8 additional individual P. cinereus were fed L. alienus, and the remaining 8 individual P. cinereus were fed L. nearticus. For the second week of trials, individual P. cinereus were assigned ant species by the flipping of a coin. Prior week data were used to determine which individuals ate which ant species. After that was determined, the heads face value on the coin was assigned one ant species which an individual was not yet fed and the tails value on the coin was assigned the other ant species which an individual was not yet fed. In the third week of trials, the previous 2 weeks’ data were used to determine which individuals had been fed which ant species. Based on that information, individuals were fed an ant species they that had not yet been fed in the prior 2 weeks of the experiment.
  7. 7. 7 Every feeding trial was ran for a duration of 1 hour. The hour feeding duration was initiated once an individual P. cinereus attacked and ate its first ant. Latency to attack was not collect if the time recorded was longer than 15 minutes. For each feeding trial, 10 individuals of each species were presented in each individual salamander’s petri dish. Chemical Evaluation When each colony of the 3 species of ants were collected, 5 individuals from each colony were immediately collected and placed into a vial filled with a 2 ml of a 70% methanol solution. Three vials of 70% methanol extract of each species were analyzed by using gas chromatography mass spectral analysis (GC-MS) (Saporito et al, 2004) to determine the chemical compounds present in the 3 ant species; A. picea, L. alienus, and L. nearticus. Each 70% methanol extract sample took 29 minutes to run though the GC-MS. Statistical Analysis We used a repeated measures analysis (SPSS Version 21) to compare the total number of ants consumed by each 1 of the individual 24 P. cinereus during the feeding experiment and the total number of each of the 3 individual ant species consumed during the feeding experiment. Repeated measures analysis (SPSS Version 21) was also used to compare latency to first attack between each 1 of the individual 24 P. cinereus used in the feeding experiment and the latency to first attack between each of the 3 individual ant species during the feeding experiment. Results Feeding Experiment Twenty-four individual striped female P. cinereus were fed 3 different species of ants; A. picea, L. alienus, and L. nearticus over a consecutive 3 week time frame. Latency to first attack was collected for most P. cinereus individuals except for those individuals that failed to attack
  8. 8. 8 within 15 minutes. Individuals who did not attack within the first 15 minutes were considered to be “unresponsive” (Jaeger and Bernard, 1981), however, these individuals were still allowed to feed on ants for 1 hour and were assigned a latency to first attack of 900 seconds (15 minutes). We found significant differences among the number of ants eaten (df Hypothesis=2, df Error=46, F=15.439, and p<0.001) and no significance among the number of ants each individual P. cinereus ate (df Hypothesis=23, df Error=46, F=2.160, p=0.013). After analyzing the latency results, we detected significant differences in latency to first attack among individual salamanders (df Hypothesis=23, df Error=46, F=1.878, p=0.034), and a significant effect of ant species on latency to first attack among individual salamanders (df Hypothesis=2, df Error=23, F=2.808, p=0.071). We also recorded if any P. cinereus were attacked by ants during the feeding experiment. There was a slightly significant effect indicated by 1 x 3 chi square analysis on the mean number of ants eaten of each of the three species when compared to the total number of times an individual P. cinereus was attacked (x2=5.12, df=2, P=0.077) (Figure 4). However, there was a weak correlation present to whether P. cinereus were deterred from eating ants after being attacked. Chemical Evaluation Three vials containing 5 individuals from 3 separate colonies of A. picea, L. alienus, and L. nearticus were ran through the GC-MS for 29 minutes. During the GC-MS analysis a graph was produced with peaks of compounds retentions times, representing chemical compounds found within the ants. This data were then analyzed to determine if any of these chemical compounds were chemical defenses present in any of the three species of ants. The GC-MS analysis indicated that the most abundant chemical compound within the ant species, A. picea
  9. 9. 9 and L. alienus, was a fatty acid with a retention time of about 15 minutes (Figures 5 & 6). The GC-MS analysis indicated that the 2 most abundant chemical compounds within the ant species, L. nearticus, were 2-pentadrcanone and 2-tridecanone; which is a volatile chemical compound used as defense chemical against predators and other ants (Regnier and Wilson, 1969). L. alienus also exhibited this compound, but only in trace amounts. Discussion Our results suggest that P. cinereus forage selectively between the three ant species; A. picea, L. alienus, and L. nearticus (Figures 1, 2, 3, & 4). Recent studies indicated that A. picea is commonly consumed in the spring and summer and became rare in the environment during the fall. However it was preferentially sought out by P. cinereus remaining abundant in their diet, making up the largest portion of the formicid diet of salamanders (37.2%) (Paluh et al, under review). L. alienus was suggested to be avoided in the fall season, but was prevalent in P. cinereus diets in the spring and summer (5.8% of diet) (Paluh et al, under review). However, our data shows differently, salamanders tended to prefer both A. picea and L. alienus at about the same rate (Figures 1 & 2) and avoided L. nearticus (Figure 4). A. picea most commonly nest under rocks, logs, limbs, barks of rotten logs, and under barks of logs in often moderately large colonies (Coover, 2005), L. alienus most commonly nest under rocks, logs and bark in typically large and vigorous colonies (Coover, pgs. 120-121), and L. nearticus most commonly nest in soil and under rocks and logs in small colonies (Coover, pgs. 124-125). All three of these species colonies are located in similar habitats to that of P. cinereus; however, they were preferred at different rates. This idea of similar habitats between P. cinereus and the ant species; A. picea and L. alienus, indicates why salamanders may have preferred this species of ant, but does not explain why salamanders would not prefer the ant
  10. 10. 10 species, L. nearticus, as well especially given that they have small colonies that would be less able to mount a defense against an intruding salamander. Therefore, there must be something chemically different between the three ant species indicating why P. cinereus would avoid one species and prefer the two other species. There have been at least 12 volatile compounds described in the ant species, L. alienus, which are used in alarm communication within the colonies and for combat defense of predators and other ants (Regnier and Wilson, 1969). Paluh et al (under review) hypothesized this to be one reason why L. alienus was avoided by P. cinereus, however, our data our data suggest otherwise, indicating that even with these volatile defense chemicals, P. cinereus preferred L. alienus at about the same rate as A. picea. This is probably due to the small trace amounts that were detected through chemical analysis. These results support the data collected by Maerz et al (2005) indicating that L. alienus was the fourth most common ant species in P. cinereus diet from data collected in Pennsylvania and New York. The least eaten species of ant, L. nearticus, contains the same 12 volatile compounds as the ant species, Lasius alienus, however, the presence of these compounds were found in L. nearticus at a much higher rate though GC-MS (Figures 6 & 7). During the feeding experiment, Plethodon cinereus was observed multiple times attacking L. nearticus, but soon after spat out the individual that was attacked. Following the rejection of eating this species the individual salamanders were observed rubbing their nose against the most paper substrate at the bottom of the petri dish. Taste-rejection, the assessment of palatability or toxicity of food after an attack that involves oral contact and sometimes ingestion of a small portion of the food item, is a method used by predators to evaluate chemical prey defenses (Lindquist, 1996; Sillen-Tullberg, 1985;
  11. 11. 11 Skelhorn and Rowe, 2006; Wiklund and Jarvi 1982). Through taste-rejection a predator is able to determine, either through taste specifically or through minor intoxication, the relative toxicity of a prey item (Avila at el, 2011). Taste-rejection occurs well after prey have been captured, thus requiring direct contact between the predator and prey (Avila at el, 2011). All of these taste-rejection observations were only made during the feeding experiment with the ant species, L. nearticus, indicating that their volatile compounds work as an anti-predatory defense against P. cinereus. The most abundant volatile compound found in this species was the compound, 2- tridecanone (Figure 7). Morgan et al (2005) describes 2-tridecanone as a long hydrocarbon chain with a ketone, which is used as a defensive chemical against other ants and predators (Regnier and Wilson, 1969). Optimal foraging theory predicts that predators will rank all potential types of prey by their profitability and then specialize on the most profitable type when it is abundant (Jaeger and Rubin, 1982). Our findings show correlation with this theory through the foraging behavior exhibited by P. cinereus during the feeding trials. The idea that P. cinereus foraged on A. picea and L. alienus at about the same rate indicates that they specialized on those prey types that are most profitable, because of their high caloric values exhibited through the GC-MS analysis (Figures 5 & 6). There were selective differences present between these two species that were preferred in terms of latency to first attack. Latency to first attack on L. alienus occurred in a shorter time span than latency to first attack on A. picea. Also L. alienus was eaten at a steadier rate when compared to the number of ants eaten and latency to first attack when compared to the rate at which A. picea was eaten when compared to latency to first attack (Figures 1 & 2). The highest average latency to first attack (526 seconds) was calculated within A. picea and the lowest average latency to first attack (319
  12. 12. 12 seconds) was observed in L. alienus. This may indicate that P. cinereus prefers to forage on L. alienus more so than A. picea. Another reason why salamanders may prefer L. alienus slightly more over A. picea could be because of the more aggressive behavior exhibited by A. picea (Figure 4). In nature, L. alienus benefits from occurring in large colonies, but in our experiment that component was removed, only providing 10 ants. This may explain the differences between our results and Paluh et al’s results. Plethodon cinereus tended to avoid L. nearticus because of their aggressive behavior that was exhibited and volatile chemicals when ingested (Figure 7). However, our results indicated that P.cinereus had the second lowest average latency (385 seconds) to first attack on this ant species. The species within the genus Lasius could have been more readily detected by salamanders, because of the volatile chemical compound, 2-tridecanone. This compound could be both good and bad for ant prey. It seems that P. cinereus was able to detect this volatile compound in L. alienus and L. nearticus though their vomernasal sensory organ making it more easy for salamanders to forage for these species (Figures 2, 3, 6, & 7). If this chemical compound was found in high concentration within an ant species then it was an effective defensive component against predators (i.e. L. nearticus) (Figure 7). This study demonstrates that P. cinereus, a known generalist that feeds on a broad variety of invertebrates (Burton, 1976) may exhibit selective foraging on certain invertebrates over others, specifically ants. Ants make up a large portion of salamander’s diets (33% of prey taken) within northeastern Ohio (Ivanov et al, 2011). The most important finding within this study is that P. cinereus was able to accurately determine that L. nearticus was an unprofitable prey through taste-rejection. More importantly salamanders may prefer one species over another for caloric value or avoid a species, because of high concentrations of volatile chemicals. Also P.
  13. 13. 13 cinereus exhibited that the use of chemical cues through vomernasal sensory is an important adaptation for detecting prey during foraging. This data then changes the understanding of leaf litter tropic interactions between guilds and tropic level interactions. Since ants have the ability to physically and chemically alter the soil environment which in turn indirectly affects plants and other organisms inhabiting the leaf litter (Holldobler and Wilson, 1990), be selectively preyed on or avoid could drastically change the biodiversity of forests from one region to another. Acknowledgments We thank both Doan Brook Watershed and The West Woods for allowing use to use their properties to obtain ants. We also thank John Carroll Department of Chemistry for allowing us to use the GC-MS for data analysis and Dr. Ralph Saporito for helping in determining the chemical compounds found within each ant species.
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  17. 17. 17 FIGURE LEGENDS Figure 1: Latency in seconds to first attack on ant species Aphaenogaster picea as a function of Aphaenogaster picea eaten in an hour feeding time period by Plethodon cinereus (n=24). As latency to first attack increased, the number of Aphaenogaster picea eaten decreased at a relatively rapid rate. Data were collected on October 25, 2014, November 2, 2014, and November 9, 2014. Figure 2: Latency in seconds to first attack on ant species Lasius alienus as a function of Lasius alienus eaten in an hour feeding time period by Plethodon cinereus (n=24). As latency to first attack increased, the number of Lasius alienus eaten slightly increased. Data were collected on October 25, 2014, November 2, 2014, and November 9, 2014. Figure 3: Latency in seconds to first attack on ant species Lasius nearticus as a function of Lasius nearticus eaten in an hour feeding time period by Plethodon cinereus (n=24). As latency to first attack increased, the number of Lasius nearticus eaten slightly increased. Data were collected on October 25, 2014, November 2, 2014, and November 9, 2014. Figure 4: Mean number of ants eaten (Aphaenogaster picea, Lasius alienus, and Lasius nearticus) by Plethodon cinereus (n=24) compared to the number of times each individual ant species attacked an individual P. cinereus during the feeding experiment. Figure 5: Gas chromatography mass spectral analysis (GC-MS) graph produced indicating the compounds found in the ant species, Aphaenogaster picea. The largest peak produced with the retention time of 15 minutes indicates fatty acids as the most abundant chemical compound within A. picea. Figure 6: Gas chromatography mass spectral analysis (GC-MS) graph produced indicating the compounds found in the ant species, Lasius alienus. The largest peak produced with the
  18. 18. 18 retention time of 15 minutes indicates fatty acids as the most abundant chemical compound within L. alienus. This sample also contained the chemical compound, 2-tridacanone (a defensive (volatile) chemical compound), which had a retention time of about 8 minutes and 11 minutes, however, it was present in small amounts. Figure 7: Gas chromatography mass spectral analysis (GC-MS) graph produced indicating the compounds found in the ant species, Lasius nearticus. The 2 largest peaks produced with the retention times at about 8 minutes and 11 minutes represent an isomer known as, 2-tridecanone (a defensive (volatile) chemical compound).
  19. 19. 19 0 1 2 3 4 5 6 7 8 9 0 100 200 300 400 500 600 700 800 900 1000 NumberofAphaeanogasterpiceaeaten Latency(seconds)to firstattack
  20. 20. 20 0 1 2 3 4 5 6 7 8 9 10 0 100 200 300 400 500 600 700 800 900 1000 NumberofLasiusalienuseaten Latency (seconds) to fistattack
  21. 21. 21 0 1 2 3 4 5 6 0 100 200 300 400 500 600 700 800 900 1000 NumberofLasiusnearticuseaten Latency (seconds) to firstattack
  22. 22. 22 0 2 4 6 8 10 12 14 16 Apeanogaster picea Lasius alienus Lasius nearcticus Mean number of ants eaten Times attacked by ants
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