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Mark A Elgar - One of the best experts on this subject based on the ideXlab platform.
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Task-Specific Recognition Signals Are Located on the Legs in a Social Insect
Frontiers in Ecology and Evolution, 2019Co-Authors: Qike Wang, Jason Q. D. Goodger, Ian E. Woodrow, Le Chang, Mark A ElgarAbstract:Task allocation ensures a high level of organization within Social Insect colonies. Workers reveal their task assignment through cuticular hydrocarbon (CHC) signals. The source and chemical composition of these signals are largely unknown. We ask whether task recognition signals are located on particular body parts of workers of Australian meat ants (Iridomyrmex purpureus). We analysed the CHC profile on the antennae, legs and abdomens of workers engaged in different tasks. Discriminant analysis showed that the leg profile is the best indicator of task identification. Behavioural assays confirmed this finding: workers typically reacted differently to non-nestmates engaged in different tasks, but not if the CHCs on the legs of their opponents were removed by a solvent. Lasso and Elastic-Net Regularized Generalized Linear Model (GLMNET) revealed which CHC components show the highest correlation in task and nestmate recognition, suggesting that Social Insects can simultaneously convey different CHC signals on different body parts, thereby allowing efficient signaling and signal perception.
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Location-specific cuticular hydrocarbon signals in a Social Insect.
Proceedings of The Royal Society B: Biological Sciences, 2016Co-Authors: Qike Wang, Jason Q. D. Goodger, Ian E. Woodrow, Mark A ElgarAbstract:Social Insects use cuticular hydrocarbons (CHCs) to convey different Social signals, including colony or nest identity. Despite extensive investigations, the exact source and identity of CHCs that ...
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location specific cuticular hydrocarbon signals in a Social Insect
Proceedings of The Royal Society B: Biological Sciences, 2016Co-Authors: Qike Wang, Jason Q. D. Goodger, Ian E. Woodrow, Mark A ElgarAbstract:Social Insects use cuticular hydrocarbons (CHCs) to convey different Social signals, including colony or nest identity. Despite extensive investigations, the exact source and identity of CHCs that act as nest-specific identification signals remain largely unknown. Perhaps this is because studies that identify CHC signals typically use organic solvents to extract a single sample from the entire animal, thereby analysing a cocktail of chemicals that may serve several signal functions. We took a novel approach by first identifying CHC profiles from different body parts of ants (Iridomyrmex purpureus), then used behavioural bioassays to reveal the location of specific Social signals. The CHC profiles of both workers and alates varied between different body parts, and workers paid more attention to the antennae of non-nest-mate and the legs of nest-mate workers. Workers responded less aggressively to non-nest-mate workers if the CHCs on the antennae of their opponents were removed with a solvent. These data indicate that CHCs located on the antennae reveal nest-mate identity and, remarkably, that antennae both convey and receive Social signals. Our approach and findings could be valuably applied to chemical signalling in other behavioural contexts, and provide insights that were otherwise obscured by including chemicals that either have no signal function or may be used in other contexts.
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learning and discrimination of cuticular hydrocarbons in a Social Insect
Biology Letters, 2012Co-Authors: Ellen Van Wilgenburg, Antoine Felden, Donghwan Choe, Robert Sulc, Jun Luo, Kenneth J Shea, Mark A Elgar, Neil D TsutsuiAbstract:Social Insect cuticular hydrocarbon (CHC) mixtures are among the most complex chemical cues known and are important in nest-mate, caste and species recognition. Despite our growing knowledge of the nature of these cues, we have very little insight into how Social Insects actually perceive and discriminate among these chemicals. In this study, we use the newly developed technique of differential olfactory conditioning to pure, custom-designed synthetic colony odours to analyse signal discrimination in Argentine ants, Linepithema humile. Our results show that tri-methyl alkanes are more easily learned than single-methyl or straight-chain alkanes. In addition, we reveal that Argentine ants can discriminate between hydrocarbons with different branching patterns and the same chain length, but not always between hydrocarbons with the same branching patterns but different chain length. Our data thus show that biochemical characteristics influence those compounds that ants can discriminate between, and which thus potentially play a role in chemical signalling and nest-mate recognition.
Paul Schmidhempel - One of the best experts on this subject based on the ideXlab platform.
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parasitism and life history in Social Insects
2006Co-Authors: Paul SchmidhempelAbstract:Abstract – Parasites are ubiquitous and present a formidable challenge for Social Insects. Studies,especially on the model system of the European bumble bee, Bombus terrestris , and its parasiteshave shown that parasitism affects almost any trait that characterizes the life history of SocialInsects. For example, infection by the trypanosome, Crithia bombi , reduces founding success of thequeen in spring. Parasitization of workers by brood of conopid flies is associated with a shift in thetiming of reproduction in natural populations. Even the use of the immune defence machineryalone elicits severe changes, such as a shift in reproductive timing, a severe reduction in colonyreproductive performance and leads to an increased investment in immune defence capacity ofoffspring. How such selective pressures have shaped Social Insect life history is still an unansweredquestion that represents a challenge for future research. Keywords: Parasite, Social Insect, life history, coevolution, bumble bees.
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trans generational immune priming in a Social Insect
Biology Letters, 2005Co-Authors: Ben M Sadd, Yvonne Kleinlogel, Regula Schmidhempel, Paul SchmidhempelAbstract:Detecting functional homology between invertebrate and vertebrate immunity is of interest in terms of understanding the dynamics and evolution of immune systems. Trans-generational effects on immunity are well known from vertebrates, but their existence in invertebrates remains controversial. Earlier work on invertebrates has interpreted increased offspring resistance to pathogens as trans-generational immune priming. However, interpretation of these earlier studies involves some caveats and thus full evidence for a direct effect of maternal immune experience on offspring immunity is still lacking in invertebrates. Here we show that induced levels of antibacterial activity are higher in the worker offspring of the bumblebee, Bombus terrestris L., when their mother queen received a corresponding immune challenge prior to colony founding. This shows trans-generational immune priming in an Insect, with ramifications for the evolution of Sociality.
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effects of inbreeding on immune response and body size in a Social Insect bombus terrestris
Functional Ecology, 2003Co-Authors: C U Gerloff, B K Ottmer, Paul SchmidhempelAbstract:Summary 1Inbreeding can negatively affect various fitness components. Here we examine how immune response and body size of a Social Insect are affected by inbreeding, sex and ploidy. 2In the bumble-bee, Bombus terrestris (L.), the offspring of colonies resulting from brother–sister matings were compared with that of outbred colonies. Immune response was measured as the degree of encapsulation of a novel antigen, body size as the length of the radial cell in the forewings. 3Inbreeding affected neither immune response nor body size in either workers or haploid males under laboratory conditions. However, fitness characteristics varied significantly among maternal families and colonies. The lack of detectable inbreeding depression for two fitness components might help explain why B. terrestris is a good colonizer in nature. 4In addition, sex and ploidy strongly affected the fitness components studied: diploid males had a significantly lower immune response than haploid males, who in turn had a significantly lower immune response than workers of the same colony. The body size of diploid males was intermediate between the body size of workers and haploid males.
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genetic variation within Social Insect colonies reduces parasite load
Proceedings of The Royal Society B: Biological Sciences, 1998Co-Authors: Stephan Liersch, Paul SchmidhempelAbstract:In colonies of Social Hymenoptera (ants, bees and wasps), workers are often not very closely related to each other, because queens mate with several different males (polyandry) or because several functional queens are present (polygyny). Both characteristics increase genetic variation among the queens' reproductive and worker offspring, but the benefits of this increased variation remain obscure. Here we report an experiment where genetically homogeneous and genetically heterogeneous colonies of the bumble bee, Bombus terrestris, have been exposed to parasitism under field conditions. Colonies of high or low genetic variation were achieved by adding and removing brood from donor colonies. The results showed a consistent effect in that genetically variable colonies experienced reduced parasite loads, i.e. lower prevalence, intensity and parasite species richness, for a range of protozoa, nematodes, mites or parasitoids affecting the workers. We therefore propose that polyandry and/or polygyny of Social Insects may be beneficial under parasitism.
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parasites and the advantage of genetic variability within Social Insect colonies
Proceedings of The Royal Society B: Biological Sciences, 1991Co-Authors: Jacqui A Shykoff, Paul SchmidhempelAbstract:Genetic variability within colonies of euSocial Insects is often higher than expected if kin selection alone explains Sociality. Parasites and pathogens have been proposed as selective agents maintaining genetic variability in populations and promoting polyandry in Social Insects. Using the natural system, bumble bees, Bombus terrestris, and their trypanosome parasites, Crithidia bombi, we find that hosts vary in susceptibility or parasites in infectiousness, and that parasite transmission in Social groups correlates with genetic relatedness among hosts. Therefore parasite-mediated negative frequency-dependent selection could play an important role in structuring the genetic composition of Social groups by counteracting kin selection for high relatedness.
Qike Wang - One of the best experts on this subject based on the ideXlab platform.
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Task-Specific Recognition Signals Are Located on the Legs in a Social Insect
Frontiers in Ecology and Evolution, 2019Co-Authors: Qike Wang, Jason Q. D. Goodger, Ian E. Woodrow, Le Chang, Mark A ElgarAbstract:Task allocation ensures a high level of organization within Social Insect colonies. Workers reveal their task assignment through cuticular hydrocarbon (CHC) signals. The source and chemical composition of these signals are largely unknown. We ask whether task recognition signals are located on particular body parts of workers of Australian meat ants (Iridomyrmex purpureus). We analysed the CHC profile on the antennae, legs and abdomens of workers engaged in different tasks. Discriminant analysis showed that the leg profile is the best indicator of task identification. Behavioural assays confirmed this finding: workers typically reacted differently to non-nestmates engaged in different tasks, but not if the CHCs on the legs of their opponents were removed by a solvent. Lasso and Elastic-Net Regularized Generalized Linear Model (GLMNET) revealed which CHC components show the highest correlation in task and nestmate recognition, suggesting that Social Insects can simultaneously convey different CHC signals on different body parts, thereby allowing efficient signaling and signal perception.
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Location-specific cuticular hydrocarbon signals in a Social Insect.
Proceedings of The Royal Society B: Biological Sciences, 2016Co-Authors: Qike Wang, Jason Q. D. Goodger, Ian E. Woodrow, Mark A ElgarAbstract:Social Insects use cuticular hydrocarbons (CHCs) to convey different Social signals, including colony or nest identity. Despite extensive investigations, the exact source and identity of CHCs that ...
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location specific cuticular hydrocarbon signals in a Social Insect
Proceedings of The Royal Society B: Biological Sciences, 2016Co-Authors: Qike Wang, Jason Q. D. Goodger, Ian E. Woodrow, Mark A ElgarAbstract:Social Insects use cuticular hydrocarbons (CHCs) to convey different Social signals, including colony or nest identity. Despite extensive investigations, the exact source and identity of CHCs that act as nest-specific identification signals remain largely unknown. Perhaps this is because studies that identify CHC signals typically use organic solvents to extract a single sample from the entire animal, thereby analysing a cocktail of chemicals that may serve several signal functions. We took a novel approach by first identifying CHC profiles from different body parts of ants (Iridomyrmex purpureus), then used behavioural bioassays to reveal the location of specific Social signals. The CHC profiles of both workers and alates varied between different body parts, and workers paid more attention to the antennae of non-nest-mate and the legs of nest-mate workers. Workers responded less aggressively to non-nest-mate workers if the CHCs on the antennae of their opponents were removed with a solvent. These data indicate that CHCs located on the antennae reveal nest-mate identity and, remarkably, that antennae both convey and receive Social signals. Our approach and findings could be valuably applied to chemical signalling in other behavioural contexts, and provide insights that were otherwise obscured by including chemicals that either have no signal function or may be used in other contexts.
Deborah M Gordon - One of the best experts on this subject based on the ideXlab platform.
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the organization of work in Social Insect colonies
Complexity, 2002Co-Authors: Deborah M GordonAbstract:A Social Insect colony operates without any central control; no one is in charge, and no colony member directs the behavior of another. A worker cannot assess the needs of the colony. How do individual workers, using fairly simple, local information, in the aggregate produce the behavior of colonies? The dynamics of colony behavior results in task allocation [1]. Colonies perform various tasks, such as foraging, care of the young, and nest construction. As environmental conditions and colony needs change, so do the numbers of workers engaged in each task. For example, when more food is available or there are more larvae to feed, more foragers may work to collect food. Task allocation is the process that adjusts the numbers of workers engaged in each task in a way appropriate to the current situation. I study task allocation in harvester ants (Pogonomyrmex barbatus) [2]. Inside the nest, ants care for the brood (the preadult forms: eggs, larvae, and pupae); process and store seeds; construct and maintain chambers; and simply stand around doing nothing. The ants that work outside the nest are a distinct group, apparently older than the interior workers. I divide the behavior I see outside the nest into four tasks: foraging, searching for and retrieving food; patrolling, assessing food supply and the presence of foragers from neighboring colonies; midden work, sorting the colony refuse pile or midden; and nest maintenance work, the construction and clearing of chambers inside the underground nest. Tasks are interdependent; numbers engaged in one task depend on numbers engaged in another [3,4]. Ants switch tasks, though not all transitions are possible. In harvester ants, task switching funnels ants into foraging and away from tasks inside the nest [4]. An ant’s decision whether to perform a task depends, first, on cues about the physical state of the environment: for example, if part of the nest is damaged, more ants do nest maintenance work to repair it. Task decisions also depend on Social cues arising from interactions with other ants. Workers from different task groups meet as they come in and out of the nest. The rate at which one ant encounters others influences its task decisions. The pattern of interactions among ants as they move around can be seen as a kind of ad hoc, dynamical network [5,6]. Task allocation is the process that adjusts the numbers of workers engaged in each task in a way appropriate to the current situation. DEBORAH M. GORDON
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the organization of work in Social Insect colonies
Complexity, 2002Co-Authors: Deborah M GordonAbstract:A Social Insect colony operates without any central control; no one is in charge, and no colony member directs the behavior of another. A worker cannot assess the needs of the colony. How do individual workers, using fairly simple, local information, in the aggregate produce the behavior of colonies? The dynamics of colony behavior results in task allocation [1]. Colonies perform various tasks, such as foraging, care of the young, and nest construction. As environmental conditions and colony needs change, so do the numbers of workers engaged in each task. For example, when more food is available or there are more larvae to feed, more foragers may work to collect food. Task allocation is the process that adjusts the numbers of workers engaged in each task in a way appropriate to the current situation. I study task allocation in harvester ants (Pogonomyrmex barbatus) [2]. Inside the nest, ants care for the brood (the preadult forms: eggs, larvae, and pupae); process and store seeds; construct and maintain chambers; and simply stand around doing nothing. The ants that work outside the nest are a distinct group, apparently older than the interior workers. I divide the behavior I see outside the nest into four tasks: foraging, searching for and retrieving food; patrolling, assessing food supply and the presence of foragers from neighboring colonies; midden work, sorting the colony refuse pile or midden; and nest maintenance work, the construction and clearing of chambers inside the underground nest. Tasks are interdependent; numbers engaged in one task depend on numbers engaged in another [3,4]. Ants switch tasks, though not all transitions are possible. In harvester ants, task switching funnels ants into foraging and away from tasks inside the nest [4]. An ant’s decision whether to perform a task depends, first, on cues about the physical state of the environment: for example, if part of the nest is damaged, more ants do nest maintenance work to repair it. Task decisions also depend on Social cues arising from interactions with other ants. Workers from different task groups meet as they come in and out of the nest. The rate at which one ant encounters others influences its task decisions. The pattern of interactions among ants as they move around can be seen as a kind of ad hoc, dynamical network [5,6]. Task allocation is the process that adjusts the numbers of workers engaged in each task in a way appropriate to the current situation. DEBORAH M. GORDON
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genetic basis for queen worker dimorphism in a Social Insect
Proceedings of the National Academy of Sciences of the United States of America, 2002Co-Authors: Veronica P Volny, Deborah M GordonAbstract:EuSocial Insects are characterized by reproductive division of labor, cooperative brood care, and the presence of a sterile worker caste. It is generally accepted that caste determination, including the differentiation of females into sterile workers and reproductive queens, is determined by environmental factors. In contrast, we find that in the red harvester ant, Pogonomyrmex barbatus, an individual's genotype at a particular microsatellite locus predicts its caste. We propose that this microsatellite locus is in tight linkage disequilibrium with at least one locus that plays an important role in caste determination. We call this the caste locus. We hypothesize that the system of caste determination we observe segregates the population into two distinct genetic lineages, each of which has distinct alleles at the microsatellite locus and also has distinct alleles, we propose, at caste. Workers are the offspring of parents from different lineages, and are thus heterozygous at caste, whereas queens are the offspring of parents from the same lineage, and are, therefore, homozygous at caste. This mode of caste determination has important consequences for the evolution of multiple mating by females and for control of the sex ratio and reproductive allocation in Social Insect colonies.
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the organization of work in Social Insect colonies
Nature, 1996Co-Authors: Deborah M GordonAbstract:In Social Insect colonies, workers perform a variety of tasks, such as foraging, brood care and nest construction. As the needs of the colony change, and as resources become available, colonies adjust the numbers of workers engaged in each task. Task allocation is the process that results in specific workers being engaged in specific tasks, in numbers appropriate to the current situation.
Nicolas Châline - One of the best experts on this subject based on the ideXlab platform.
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drifting behaviour as an alternative reproductive strategy for Social Insect workers
Proceedings of The Royal Society B: Biological Sciences, 2013Co-Authors: Pierre Blacher, Boris Yagound, Emmanuel Lecoutey, Paul Devienne, Stephane Chameron, Nicolas ChâlineAbstract:Restricted reproduction is traditionally posited as the defining feature of euSocial Insect workers. The discovery of worker reproduction in foreign colonies challenges this view and suggests that workers’ potential to pursue selfish interests may be higher than previously believed. However, whether such reproductive behaviour truly relies on a reproductive decision is still unknown. Workers’ reproductive decisions thus need to be investigated to assess the extent of workers’ reproductive options. Here, we show in the bumblebee Bombus terrestris that drifting is a distinct strategy by which fertile workers circumvent competition in their nest and reproduce in foreign colonies. By monitoring workers’ movements between colonies, we show that drifting is a remarkably dynamic behaviour, widely expressed by both fertile and infertile workers. We demonstrate that a high fertility is, however, central in determining the propensity of workers to enter foreign colonies as well as their subsequent reproduction in host colonies. Moreover, our study shows that the drifting of fertile workers reflects complex decision-making processes associated with in-nest reproductive competition. This novel finding therefore adds to our modern conception of cooperation by showing the previously overlooked importance of alternative strategies which enable workers to assert their reproductive interests.
