The Experts below are selected from a list of 309 Experts worldwide ranked by ideXlab platform
Sean O'donnell - One of the best experts on this subject based on the ideXlab platform.
-
The development of biting interactions and task performance in a tropical eusocial wasp
Behaviour, 2003Co-Authors: Sean O'donnellAbstract:Summary Swarm-founding wasp workers (genus Polybia) exhibit developmental changes in task specialization known as temporal Polyethism. Young workers typically remain inside the nest, followed by a period of working on the exterior nest surface, and later by foraging. Polybia workers on the nest exterior engage in biting interactions with their nest mates, and workers that are bitten are more likely to forage. To assess whether biting interactions ine uence the rate of temporal Polyethism in P. aequatorialis , I tested for associations between on-nest workers’ receiving biting and their ages at onset of foraging. As predicted, most workers were bitten several days before they began foraging. Workers that were bitten sooner after appearing on the nest surface also began foraging sooner. Furthermore, workers that were bitten at higher rates began foraging at younger ages. These patterns suggest that biting interactions play a role in initiating the onset of foraging. Most workers continued to receive biting after they began foraging, and workers were more likely to depart the nest immediately after being bitten. Therefore, biting apparently also functions to maintain foraging behaviour.
-
Worker age, ovary development, and temporal Polyethism in the swarm-founding wasp Polybia occidentalis (Hymenoptera: Vespidae)
Journal of Insect Behavior, 2001Co-Authors: Sean O'donnellAbstract:I measured oocyte sizes of Polybia occidentalis workers to assess whether ovary development corresponded with adult age or with individual variation in behavior. Workers exhibited temporal Polyethism by first working inside the nest, then performing on-nest tasks, and later foraging and defending the nest. Individuals varied in their ages at first performance of each of these sets of behavioral acts. Ovary development corresponded strongly with adult age. Workers' ovaries declined quickly after an initial phase of partial development. The period of ovary decline overlapped with the age range at which most workers began performing tasks on the exterior nest surface. However, after accounting for age effects, individual behavioral differences (rate of temporal Polyethism and performance of foraging and defense tasks) did not correspond with ovary development. These data suggest that ovary development had little or no effect on variation in task performance by P. occidentalis workers on the nest surface.
-
Dominance and Polyethism in the eusocial wasp Mischocyttarus mastigophorus (Hymenoptera: Vespidae)
Behavioral Ecology and Sociobiology, 1998Co-Authors: Sean O'donnellAbstract:Dominance interactions affected patterns of non-reproductive division of labor (Polyethism) in the eusocial wasp Mischocyttarus mastigophorus. Socially dominant individuals foraged for food (nectar and insect prey) at lower rates than subordinate individuals. In contrast, dominant wasps performed most of the foraging for the wood pulp used in nest construction. Social dominance also affected partitioning of materials collected by foragers when they returned to the nest. Wood pulp loads were never shared with nest mates, while food loads, especially insect prey, were often partitioned with other wasps. Dominant individuals on the nest were more likely to take food from arriving foragers than subordinate individuals. The role of dominance interactions in regulating Polyethism has evolved in the eusocial paper wasps (Polistinae). Both specialization by foragers and task partitioning have increased from basal genera (independent-founding wasps, including Mischo-cyttarus spp.) to more derived genera (swarm-founding Epiponini). Dominance interactions do not regulate forager specialization or task partitioning in epiponines. I hypothesize that these changes in Polyethism were enabled by the evolution of increased colony size in the Epiponini.
-
Genetic effects on task performance, but not on age Polyethism, in a swarm-founding eusocial wasp
Animal behaviour, 1998Co-Authors: Sean O'donnellAbstract:Abstract Division of labour among workers in insect societies often includes two major components: age-related changes in behaviour (age Polyethism) and specialization in task performance. The aim of this study was to test whether similarity in inside-nest task performance and in rate of age Polyethism correspond to genetic similarity among nestmates in the polygynous eusocial wasp Polybia aequatorialis .Behavioural data were collected on marked, known-age workers from three source colonies introduced into two observation colonies in the field. Genetic similarity among workers was assessed by quantifying sharing of random amplified polymorphic DNA (RAPD) marker alleles. Workers were categorized by whether they engaged in nest cleaning as an indicator of individual differences in inside-nest task performance. Within source colonies, workers that performed nest-cleaning tasks were more genetically similar to each other than they were to workers not performing these tasks. Workers also differed in their rates of passage through the age-related task sequence, but no association was found between sharing of RAPD marker alleles and rate of age Polyethism. These results accord with earlier studies demonstrating flexibility in age Polyethism in swarm-founding wasps, and with findings that worker genotypic variability corresponds to specialization in task performance in P. aequatorialis. Polybia spp. workers rarely switch among tasks, even in response to changes in colony conditions, and workers’ genotypes may constrain flexibility in task performance at the individual level. Conversely, colonies may accrue benefits from having genotypically diverse worker forces, which could favour the maintenance of polygyny in swarm-founding wasps.
-
Division of labor in post-emergence colonies of the primitively eusocial wasp Polistes instabilis de Saussure (Hymenoptera: Vespidae)
Insectes Sociaux, 1995Co-Authors: Sean O'donnellAbstract:Polyethism was quantified in post-emergence colonies of the primitively eusocial wasp,Polistes instabilis, and compared to Polyethism in a sympatric advanced eusocial wasp,Polybia occidentalis. Like P.occidentalis, P. instabilis foragers collected food (nectar and prey) and nest materials (wood pulp and water).P. instabilis foragers showed some evidence of specialization with respect to which materials they gathered, but most foragers, divided their effort among food and nest materials, a pattern that is rarely seen inP. occidentalis. In colonies of both species, more foragers collected nectar than any other material; in contrast, most water foraging was performed by one or two workers. Upon returning to the nest,P. instabilis foragers gave up part or all of most nectar, prey, and pulp loads to nestmates, while water was rarely partitioned. Prey loads were most likely to be given up entirely.P. instabilis workers show evidence of conflict over the handling of materials at the nest. The frequency with which workers took portions of nectar loads from forgers was positively correlated with their frequency of aggressive dominant behavior, and with their frequency of taking other foraged materials. Compared to Polyethism inP. occidentalis P. instabilis showed less individual specialization on foraging tasks and less partitioning of foraged materials with nestmates, suggesting that these characteristics of Polyethism have been modified during the evolution of advanced insect societies.
Raghavendra Gadagkar - One of the best experts on this subject based on the ideXlab platform.
-
The effect of age on non-reproductive division of labour in the tropical primitively eusocial wasp, Ropalidia cyathiformis
The International journal of developmental biology, 2020Co-Authors: Sruthi Unnikrishnan, Raghavendra GadagkarAbstract:Division of labour among workers (non-reproductive division of labour), a characteristic feature of eusocial insects enables the efficient functioning of their colonies. In many advanced insect societies division of labour is based on age (age Polyethism). Primitively eusocial insects however are believed to have a weak age Polyethism. Here we investigated the role of age in non-reproductive division of labour in the tropical primitively eusocial wasp, Ropalidia cyathiformis and compared it with that in Ropalidia marginata, a congeneric species that exhibits relatively strong age Polyethism. Age had a significant effect on the first performance of the four tasks studied; tasks were initiated in the sequence feed larva, build, bring food and bring building material. We measured task performance as the absolute frequency of tasks performed (FTP) and the probability of performing a task relative to other tasks (PTP) and age as absolute age in days since eclosion as well as relative age compared to nestmates. FTP varied significantly with both absolute and relative age, although absolute age explained more variance. PTP varied significantly with absolute age but not always with relative age. This is contrary to R. marginata, where more variation is explained by relative age than by absolute age. There was no trade-off between intranidal and extranidal tasks in R. cyathiformis unlike in R. marginata where the frequency of intranidal tasks decreased and that of extranidal tasks increased with age. We conclude that age Polyethism is weak and less flexible in R. cyathiformis compared to that in R. marginata.
-
Hard working nurses rather than over-aged nurses permit Ropalidia marginata to respond to the loss of young individuals
Insectes Sociaux, 2004Co-Authors: Maulishree Agrahari, Raghavendra GadagkarAbstract:The primitively eusocial wasp Ropalidia marginata exhibits a remarkably well-developed honey bee like age Polyethism. Individuals perform different tasks sequentially as they age, starting with intranidal tasks (nursing and building in that order) and ending with extranidal tasks (foraging for pulp and food in that order). As in the case of honey bees such age Polyethism is rather flexible; in the absence of old individuals (in young-cohort colonies), precocious foragers forage at abnormally young ages. Here we demonstrate that the absence of young individuals (in old-cohort colonies) does not result in over-aged nurses nursing at abnormally old ages, as seen in the case of honey bees. Instead it results in hard working nurses who nurse at abnormally high rates. The possible reasons for the absence of over-aged nurses and the presence of hard working nurses are discussed.
-
Juvenile hormone accelerates ovarian development and does not affect age Polyethism in the primitively eusocial wasp, Ropalidia marginata.
Journal of insect physiology, 2003Co-Authors: Maulishree Agrahari, Raghavendra GadagkarAbstract:Juvenile hormone modulates post-imaginal reproductive division of labor in primitively eusocial species and promotes the production of queens (e.g., Polistes) while it modulates age Polyethism and promotes the production of foragers in highly eusocial species (e.g., the honey bee). Ropalidia marginata is a primitively eusocial wasp that shows both post-imaginal regulation of reproductive division of labor as well as age Polyethism. Hence, R.marginata is a particularly interesting model system to study the effect of juvenile hormone. We demonstrate here that a single, topical application of 100 μg of juvenile hormone-III per female wasp accelerates ovarian development of wasps held in isolation. Similar application to wasps released back on to their natal nests has no effect on their rate of behavioral development as witnessed from the age of first performance of feed larva, build, bring pulp and bring food. We conclude therefore that in R.marginata, juvenile hormone has retained its function of modulating reproductive division of labor and has not acquired the function of modulating age Polyethism.
Gene E. Robinson - One of the best experts on this subject based on the ideXlab platform.
-
Social inhibition and the regulation of temporal Polyethism in honey bees.
Journal of theoretical biology, 2001Co-Authors: S.n. Beshers, Z.y. Huang, Yoshitsugu Oono, Gene E. RobinsonAbstract:Honey bee division of labor is characterized by temporal Polyethism, in which young workers remain in the hive and perform tasks there, whereas old workers perform more risky outside tasks, mainly foraging. We present a model of honey bee division of labor based on (1) an intrinsic process of behavioral development and (2) inhibition of development through social interactions among the workers in a colony. The model shows that these two processes can explain the main features of honey bee temporal Polyethism: the correlation between age and task performance; the age at which a worker first forages and how this age varies among hives; the balanced allocation of workers to hive tasks and foraging; the recovery of a colony from demographic perturbations; and the differentiation of workers into different behavioral roles. The model provides a baseline picture of individual and colony behavior that can serve as the basis for studies of more fine-grained regulation of division of labor.
-
Genetic variation in worker temporal Polyethism and colony defensiveness in the honey bee, Apis mellifera
Behavioral Ecology, 2000Co-Authors: Tugrul Giray, Ernesto Guzman-novoa, Carol W. Aron, Benjamin Zelinsky, Susan E. Fahrbach, Gene E. RobinsonAbstract:To test the hypothesis that colonies of honey bees composed of workers with faster rates of adult behavioral development are more defensive than colonies composed of workers with slower behavioral development, we determined whether there is a correlation between genetic variation in worker temporal Polyethism and colony defensiveness. There was a positive correlation for these two traits, both for European and Africanized honey bees. The correlation was larger for Africanized bees, due to differences between Africanized and European bees, differences in experimental design, or both. Consistent with these results was the finding that colonies with a higher proportion of older bees were more defensive than colonies of the same size that had a lower proportion of older bees. There also was a positive correlation between rate of individual behavioral development and the intensity of colony flight activity, and a negative correlation between colony defensiveness and flight activity. This suggests that the relationship between temporal Polyethism and colony defensiveness may vary with the manner in which foraging and defense duties are allocated among a colony’s older workers. These results indicate that genotypic differences in rates of worker behavioral development can influence the phenotype of a honey bee colony in a variety of ways.
-
Response thresholds and division of labor in insect colonies.
Information Processing in Social Insects, 1999Co-Authors: Samuel N. Beshers, Gene E. Robinson, Jay E. MittenthalAbstract:Division of labor in social insects can be explained at least in part by variation among workers in response thresholds for task-specific stimuli. In this chapter we review the origins of the response threshold concept in physiology and ethology, and show how it can be used to explain division of labor. Temporal Polyethism and physical caste Polyethism, as well as hormonal, genetic, and learning effects on task performance, may be interpreted as the results of changes in response thresholds. We then provide a more speculative discussion of the implications of the response threshold concept for understanding the behavioral programs of workers and the organization of colonies. We argue that the response threshold concept is a logical starting point for developing explanations for the proximate basis of division of labor, and that further development of this concept may be a necessary and critical step in the study of social insect behavior. In addition, more experimental work is needed to demonstrate variation in response thresholds among workers, and to show that this variation causes division of labor.
-
Colony integration in honey bees: genetic, endocrine and social control of division of labor
Apidologie, 1998Co-Authors: Gene E. Robinson, Zhi Yong HuangAbstract:This paper reviews our understanding of the mechanisms that enable adult worker honey bees to show plasticity in age Polyethism in response to changing environmental conditions. There are genotypic differences in rate of behavioral development, which predispose individu- als to respond to changing conditions in predictable ways. For example, genotypes that have relatively fast rates of behavioral development under more typical conditions are more inclined to show precocious foraging in the absence of foragers of normal age. Juvenile hormone influences rate of behavioral development, and environmentally induced changes in JH titers are thought to underlie changes in age Polyethism. Results of recent experiments indicate that changes in the age at onset of foraging caused by changes in colony age demography are at least partially a conse- quence of social interactions in which older bees inhibit the rate of behavioral development of younger bees. Chemical signals are suspected to feature prominently in these interactions, and pre- liminary evidence supporting this notion is presented. © Inra/DIB/AGIB/Elsevier, Paris
-
Common endocrine and genetic mechanisms of behavioral development in male and worker honey bees and the evolution of division of labor
Proceedings of the National Academy of Sciences, 1996Co-Authors: Tugrul Giray, Gene E. RobinsonAbstract:Abstract Temporal Polyethism is a highly derived form of behavioral development displayed by social insects. Hormonal and genetic mechanisms regulating temporal Polyethism in worker honey bees have been identified, but the evolution of these mechanisms is not well understood. We performed three experiments with male honey bees (drones) to investigate how mechanisms regulating temporal Polyethism may have evolved because, relative to workers, drones display an intriguing combination of similarities and differences in behavioral development. We report that behavioral development in drones is regulated by mechanisms common to workers. In experiment 1, drones treated with the juvenile hormone (JH) analog methoprene started flying at significantly younger ages than did control drones, as is the case for workers. In experiment 2, there was an age-related increase in JH associated with the onset of drone flight, as in workers. In experiment 3, drones derived from workers with fast rates of behavioral development themselves started flying at younger ages than drones derived from workers with slower rates of behavioral development. These results suggest that endocrine and genetic mechanisms associated with temporal Polyethism did not evolve strictly within the context of worker social behavior.
Carlos Gershenson - One of the best experts on this subject based on the ideXlab platform.
-
Polyethism in a colony of artificial ants
arXiv: Artificial Intelligence, 2011Co-Authors: Chris Marriott, Carlos GershensonAbstract:We explore self-organizing strategies for role assignment in a foraging task carried out by a colony of artificial agents. Our strategies are inspired by various mechanisms of division of labor (Polyethism) observed in eusocial insects like ants, termites, or bees. Specifically we instantiate models of caste Polyethism and age or temporal Polyethism to evaluated the benefits to foraging in a dynamic environment. Our experiment is directly related to the exploration/exploitation trade of in machine learning.
-
ECAL - Polyethism in a colony of artificial ants.
2011Co-Authors: Chris Marriott, Carlos GershensonAbstract:We explore self-organizing strategies for role assignment and strategy selection in a foraging task carried out by a colony of artificial agents. Foraging strategies are selected by strategies inspired by various mechanisms of division of labor (Polyethism) observed in eusocial insects like ants, termites, or bees. Specifically we instantiate models of caste Polyethism and age or temporal Polyethism to evaluate the benefits to foraging in a dynamic or unknown environment. We focus on the ability of division of labor mechanisms to self-organize individual strategy selection based on the environment.
-
Polyethism in a colony of artificial ants
European Conference on Artificial Life, 2011Co-Authors: Chris Marriott, Carlos GershensonAbstract:We explore self-organizing strategies for role assignment and strategy selection in a foraging task carried out by a colony of artificial agents. Foraging strategies are selected by strategies inspired by various mechanisms of division of labor (Polyethism) observed in eusocial insects like ants, termites, or bees. Specifically we instantiate models of caste Polyethism and age or temporal Polyethism to evaluate the benefits to foraging in a dynamic or unknown environment. We focus on the ability of division of labor mechanisms to self-organize individual strategy selection based on the environment.
Adam Tofilski - One of the best experts on this subject based on the ideXlab platform.
-
DOI 10.1007/s00265-001-0429-z ORIGINAL ARTICLE
2014Co-Authors: Adam TofilskiAbstract:Abstract Age Polyethism is widespread among social insects and, as a rule, safe tasks are performed by workers earlier in life than are risky ones. Mathematical models were used to compare expected longevity of workers in colonies with and without age Polyethism. The results of the models suggest that if aging does not depend on activity then age Polyethism is profitable when safer tasks are performed earlier in life. If, however, aging depends on activity, age Polyethism is profitable when safer tasks are performed earlier in life and if they are associated with higher aging-related mortality. On the other hand, age Polyethism is not profitable if safer tasks are performed later in life, and if they are associated with lower aging-related mortality. Furthermore, if there is no aging, then age Polyethism does not bring any benefits. Electronic supplementary material to this paper can be obtained by using the Springer Link server located a
-
Influence of caste Polyethism on longevity of workers in social insect colonies.
Journal of theoretical biology, 2005Co-Authors: Adam TofilskiAbstract:Different patterns of division of labor can affect the expected longevity of social insects workers. It has been earlier suggested that when tasks performed inside and outside colony are equally risky then the expected longevity of workers in colonies with caste Polyethism is greater than that in colonies without Polyethism. To verify these predictions I used a model assuming two sets of tasks, associated with different mortality rates. In the colony without Polyethism the workers preformed safe and risky tasks in turn, while in the colony with caste Polyethism the workers specialized in only one set of tasks. The outcomes suggest that the expected longevity of workers in colonies with caste Polyethism cannot be greater than that in colonies without Polyethism. Only if there is no aging and under some special and rare conditions are there no differences in expected longevity between colonies with and without caste Polyethism. If aging is independent of activity, caste Polyethism does not shorten longevity when all tasks in the colony are equally risky. The results can explain why caste Polyethism is not as widespread among social insects as age Polyethism.
-
Influence of age Polyethism on longevity of workers in social insects
Behavioral Ecology and Sociobiology, 2002Co-Authors: Adam TofilskiAbstract:Age Polyethism is widespread among social insects and, as a rule, safe tasks are performed by workers earlier in life than are risky ones. Mathematical models were used to compare expected longevity of workers in colonies with and without age Polyethism. The results of the models suggest that if aging does not depend on activity then age Polyethism is profitable when safer tasks are performed earlier in life. If, however, aging depends on activity, age Polyethism is profitable when safer tasks are performed earlier in life and if they are associated with higher aging-related mortality. On the other hand, age Polyethism is not profitable if safer tasks are performed later in life, and if they are associated with lower aging-related mortality. Furthermore, if there is no aging, then age Polyethism does not bring any benefits. Electronic supplementary material to this paper can be obtained by using the Springer Link server located at http://dx.doi.org/10.1007/s00265-001-0429-z
