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Beshers SN. Regulation of division of labor in insects: a colony-level perspective. CURRENT OPINION IN INSECT SCIENCE 2024; 61:101155. [PMID: 38109969 DOI: 10.1016/j.cois.2023.101155] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/13/2023] [Revised: 12/06/2023] [Accepted: 12/13/2023] [Indexed: 12/20/2023]
Abstract
Studies of division of labor have focused mainly on individual workers performing tasks. Here I propose a shift in perspective: colonies perform tasks, and task performance should be evaluated at the colony level. I then review studies from the recent literature from this perspective, on topics including evaluating task performance; specialization and efficiency; flexibility and task performance; response threshold models; and variation in behavior arising from diverse sensory experiences and learning. The use of specialized workers is only one of a variety of strategies that colonies may follow in performing tasks. The ability of colonies to produce consistent responses and to compensate for changes in the labor pool supports the idea of a task allocation system that precedes specialization. The colony-level perspective raises new questions about how tasks are done and the strategies used to improve colony task performance.
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Affiliation(s)
- Samuel N Beshers
- Department of Entomology, University of Illinois at Urbana-Champaign, 505 South Goodwin Avenue, Urbana, IL 61801, USA.
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2
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Navas-Zuloaga MG, Baudier KM, Fewell JH, Ben-Asher N, Pavlic TP, Kang Y. A modeling framework for adaptive collective defense: crisis response in social-insect colonies. J Math Biol 2023; 87:87. [PMID: 37966545 DOI: 10.1007/s00285-023-01995-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2022] [Revised: 08/26/2023] [Accepted: 09/07/2023] [Indexed: 11/16/2023]
Abstract
Living systems, from cells to superorganismic insect colonies, have an organizational boundary between inside and outside and allocate resources to defend it. Whereas the micro-scale dynamics of cell walls can be difficult to study, the adaptive allocation of workers to defense in social-insect colonies is more conspicuous. This is particularly the case for Tetragonisca angustula stingless bees, which combine different defensive mechanisms found across other colonial animals: (1) morphological specialization (distinct soldiers (majors) are produced over weeks); (2) age-based polyethism (young majors transition to guarding tasks over days); and (3) task switching (small workers (minors) replace soldiers within minutes under crisis). To better understand how these timescales of reproduction, development, and behavior integrate to balance defensive demands with other colony needs, we developed a demographic Filippov ODE system to study the effect of these processes on task allocation and colony size. Our results show that colony size peaks at low proportions of majors, but colonies die if minors are too plastic or defensive demands are too high or if there is a high proportion of quickly developing majors. For fast maturation, increasing major production may decrease defenses. This model elucidates the demographic factors constraining collective defense regulation in social insects while also suggesting new explanations for variation in defensive allocation at smaller scales where the mechanisms underlying defensive processes are not easily observable. Moreover, our work helps to establish social insects as model organisms for understanding other systems where the transaction costs for component turnover are nontrivial, as in manufacturing systems and just-in-time supply chains.
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Affiliation(s)
| | - Kaitlin M Baudier
- School of Biological, Environmental, and Earth Sciences, The University of Southern Mississippi, Hattiesburg, MS, 39406, USA
| | - Jennifer H Fewell
- School of Life Sciences, Arizona State University, Tempe, AZ, 85281, USA
| | - Noam Ben-Asher
- Data Science Directorate, SimSpace Cooperation, Boston, MA, USA
| | - Theodore P Pavlic
- School of Life Sciences, Arizona State University, Tempe, AZ, 85281, USA
- School of Computing and Augmented Intelligence, Arizona State University, Tempe, AZ, 85281, USA
- School of Sustainability, Arizona State University, Tempe, AZ, 85281, USA
- School of Complex Adaptive Systems, Arizona State University, Tempe, AZ, 85281, USA
| | - Yun Kang
- Sciences and Mathematics Faculty, College of Integrative Sciences and Arts, Arizona State University, Tempe, AZ, 85281, USA.
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3
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Goldberg TS, Bloch G. Inhibitory signaling in collective social insect networks, is it indeed uncommon? CURRENT OPINION IN INSECT SCIENCE 2023; 59:101107. [PMID: 37634618 DOI: 10.1016/j.cois.2023.101107] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/17/2023] [Revised: 07/30/2023] [Accepted: 08/22/2023] [Indexed: 08/29/2023]
Abstract
Individual entities across levels of biological organization interact to reach collective decisions. In centralized neuronal networks, competing neural populations commonly accumulate information over time while increasing their own activity, and cross-inhibiting other populations until one group passes a given threshold. In social insects, there is good evidence for decisions mediated by positive feedbacks, but we found evidence for similar inhibitory signals only in honey bee (Apis mellifera) stop signals, and Pharaoh's ant- (Monomorium pharaonic) repellent pheromones, with only the former occasionally being used as cross-inhibition. We discuss whether these differences stem from insufficient research effort or represent genuine differences across levels of biological organization.
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Affiliation(s)
- Tzvi S Goldberg
- Department of Ecology, Evolution and Behavior, The A. Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Israel.
| | - Guy Bloch
- Department of Ecology, Evolution and Behavior, The A. Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Israel; The Federmann Center for the Study of Rationality, The Hebrew University of Jerusalem, Israel
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4
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Grüter C, Balbuena MS, Valadares L. Mechanisms and adaptations that shape division of labour in stingless bees. CURRENT OPINION IN INSECT SCIENCE 2023; 58:101057. [PMID: 37230412 DOI: 10.1016/j.cois.2023.101057] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/06/2022] [Revised: 04/12/2023] [Accepted: 05/02/2023] [Indexed: 05/27/2023]
Abstract
Stingless bees are a diverse and ecologically important group of pollinators in the tropics. Division of labour allows bee colonies to meet the various demands of their social life, but has been studied in only ∼3% of all described stingless bee species. The available data suggest that division of labour shows both parallels and striking differences compared with other social bees. Worker age is a reliable predictor of worker behaviour in many species, while morphological variation in body size or differences in brain structure are important for specific worker tasks in some species. Stingless bees provide opportunities to confirm general patterns of division of labour, but they also offer prospects to discover and study novel mechanisms underlying the different lifestyles found in eusocial bees.
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Affiliation(s)
- Christoph Grüter
- School of Biological Sciences, University of Bristol, 24 Tyndall Avenue, BS8 1TQ, UK.
| | - María Sol Balbuena
- Laboratorio de Insectos Sociales, Departamento de Biodiversidad y Biología Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, CABA, Argentina; Instituto de Fisiología, Biología Molecular y Neurociencias (IFIBYNE), CONICET, Universidad de Ciencias Naturales y Exactas, Universidad de Buenos Aires, CABA, Argentina
| | - Lohan Valadares
- Evolution, Genomes, Behavior, and Ecology (EGCE), Université Paris-Saclay, CNRS, IRD, Gif-sur-Yvette, France
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Valadares L, Nascimento F, Châline N. Small workers are more persistent fighters than soldiers in the highly polymorphic Atta leaf-cutting ants. Anim Behav 2022. [DOI: 10.1016/j.anbehav.2022.04.013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022]
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6
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Age-based spatial distribution of workers is resilient to worker loss in a subterranean termite. Sci Rep 2022; 12:7837. [PMID: 35552445 PMCID: PMC9098853 DOI: 10.1038/s41598-022-11512-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2021] [Accepted: 04/18/2022] [Indexed: 01/13/2023] Open
Abstract
Elaborate task allocation is key to the ecological success of eusocial insects. Termite colonies are known for exhibiting age polyethism, with older instars more likely to depart the reproductive center to access food. However, it remains unknown how termites retain this spatial structure against external disturbances. Here we show that a subterranean termite Coptotermes formosanus Shiraki combines age polyethism and behavioral flexibility to maintain a constant worker proportion at the food area. Since this termite inhabits multiple wood pieces by connecting them through underground tunnels, disastrous colony splitting events can result in the loss of colony members. We simulated this via weekly removal of all individuals at the food area. Our results showed that termites maintained a worker proportion of ~ 20% at the food area regardless of changes in total colony size and demographic composition, where younger workers replaced food acquisition functions to maintain a constant worker proportion at the food area. Food consumption analysis revealed that the per-capita food consumption rate decreased with younger workers, but the colony did not compensate for the deficiency by increasing the proportion of workers at the feeding site. These results suggest that termite colonies prioritize risk management of colony fragmentation while maintaining suitable food acquisition efficiency with the next available workers in the colony, highlighting the importance of task allocation for colony resiliency under fluctuating environments.
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Valadares L, Vieira BG, Santos do Nascimento F, Sandoz JC. Brain size and behavioral specialization in the jataí stingless bee (Tetragonisca angustula). J Comp Neurol 2022; 530:2304-2314. [PMID: 35513351 DOI: 10.1002/cne.25333] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2021] [Revised: 04/11/2022] [Accepted: 04/13/2022] [Indexed: 11/08/2022]
Abstract
Social insects are instructive models for understanding the association between investment in brain size and behavioral variability because they show a relatively simple nervous system associated with a large set of complex behaviors. In the jataí stingless bee (Tetragonisca angustula), division of labor relies both on age and body size differences among workers. When young, both minors and soldiers engage in intranidal tasks and move to extranidal tasks as they age. Minors switch to foraging activities, while soldiers take over defensive roles. Nest defense performed by soldiers includes two different tasks: (1) hovering around the nest entrance for the detection and interception of heterospecific bees (a task relying mostly on vision) and (2) standing at the nest entrance tube for inspection of returning foragers and discrimination against conspecific non-nestmates based on olfactory cues. Here, using different-sized individuals (minors and soldiers) as well as same-sized individuals (hovering and standing soldiers) performing distinct tasks, we investigated the effects of both morphological and behavioral variability on brain size. We found a negative allometric growth between brain size and body size across jataí workers, meaning that minors had relatively larger brains than soldiers. Between soldier types, we found that hovering soldiers had larger brain compartments related to visual processing (the optic lobes) and learning (the mushroom bodies). Brain size differences between jataí soldiers thus correspond to behavioral specialization in defense (i.e., vision for hovering soldiers) and illustrate a functional neuroplasticity underpinning division of labor.
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Affiliation(s)
- Lohan Valadares
- Evolution, Genomes, Behavior, and Ecology (EGCE), Université Paris-Saclay, CNRS, IRD, Gif-sur-Yvette, France
| | - Bruno Gusmão Vieira
- Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, Brazil
| | - Fabio Santos do Nascimento
- Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, Brazil
| | - Jean-Christophe Sandoz
- Evolution, Genomes, Behavior, and Ecology (EGCE), Université Paris-Saclay, CNRS, IRD, Gif-sur-Yvette, France
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When being flexible matters: Ecological underpinnings for the evolution of collective flexibility and task allocation. Proc Natl Acad Sci U S A 2022; 119:e2116066119. [PMID: 35486699 PMCID: PMC9170069 DOI: 10.1073/pnas.2116066119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
A central problem in evolutionary biology is explaining variation in the organization of task allocation across collective systems. Why do human cells irreversibly adopt a task during development (e.g., kidney vs. liver cell), while sponge cells switch between different cell types? And why have only some ant species evolved specialized castes of workers for particular tasks? Although it seems reasonable to suppose that such differences reflect, at least partially, the different ecological pressures that systems face, there is no general understanding of how a system’s dynamic environment shapes its task allocation. To this end, we develop a general mathematical framework that reveals how simple ecological considerations could potentially explain cross-system variation in task allocation—including in flexibility, specialization, and (in)activity. Task allocation is a central feature of collective organization. Living collective systems, such as multicellular organisms or social insect colonies, have evolved diverse ways to allocate individuals to different tasks, ranging from rigid, inflexible task allocation that is not adjusted to changing circumstances to more fluid, flexible task allocation that is rapidly adjusted to the external environment. While the mechanisms underlying task allocation have been intensely studied, it remains poorly understood whether differences in the flexibility of task allocation can be viewed as adaptive responses to different ecological contexts—for example, different degrees of temporal variability. Motivated by this question, we develop an analytically tractable mathematical framework to explore the evolution of task allocation in dynamic environments. We find that collective flexibility is not necessarily always adaptive, and fails to evolve in environments that change too slowly (relative to how long tasks can be left unattended) or too quickly (relative to how rapidly task allocation can be adjusted). We further employ the framework to investigate how environmental variability impacts the internal organization of task allocation, which allows us to propose adaptive explanations for some puzzling empirical observations, such as seemingly unnecessary task switching under constant environmental conditions, apparent task specialization without efficiency benefits, and high levels of individual inactivity. Altogether, this work provides a general framework for probing the evolved diversity of task allocation strategies in nature and reinforces the idea that considering a system’s ecology is crucial to explaining its collective organization.
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9
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Chittka L, Rossi N. Social cognition in insects. Trends Cogn Sci 2022; 26:578-592. [DOI: 10.1016/j.tics.2022.04.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2021] [Revised: 03/26/2022] [Accepted: 04/12/2022] [Indexed: 11/25/2022]
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10
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Abbot P. Defense in Social Insects: Diversity, Division of Labor, and Evolution. ANNUAL REVIEW OF ENTOMOLOGY 2022; 67:407-436. [PMID: 34995089 DOI: 10.1146/annurev-ento-082521-072638] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
All social insects defend their colony from predators, parasites, and pathogens. In Oster and Wilson's classic work, they posed one of the key paradoxes about defense in social insects: Given the universal necessity of defense, why then is there so much diversity in mechanisms? Ecological factors undoubtedly are important: Predation and usurpation have imposed strong selection on eusocial insects, and active defense by colonies is a ubiquitous feature of all social insects. The description of diverse insect groups with castes of sterile workers whose main duty is defense has broadened the purview of social evolution in insects, in particular with respect to caste and behavior. Defense is one of the central axes along which we can begin to organize and understand sociality in insects. With the establishment of social insect models such as the honey bee, new discoveries are emerging regarding the endocrine, neural, and gene regulatory mechanisms underlying defense in social insects. The mechanisms underlying morphological and behavioral defense traits may be shared across diverse groups, providing opportunities for identifying both conserved and novel mechanisms at work. Emerging themes highlight the context dependency of and interaction between factors that regulate defense in social insects.
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Affiliation(s)
- Patrick Abbot
- Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee, USA;
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11
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Almeida FCR, Magalhães DM, Favaris AP, Rodríguez J, Azevedo KEX, Bento JMS, Alves DA. Side effects of a fungus-based biopesticide on stingless bee guarding behaviour. CHEMOSPHERE 2022; 287:132147. [PMID: 34492415 DOI: 10.1016/j.chemosphere.2021.132147] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/17/2021] [Revised: 08/31/2021] [Accepted: 09/01/2021] [Indexed: 06/13/2023]
Abstract
Pathogenic fungi have been used worldwide to control crop pests and are assumed to pose negligible threats to the survival of pollinators. Although eusocial stingless bees provide essential pollination services and might be exposed to these biopesticides in tropical agroecosystems, there is a substantial knowledge gap regarding the side effects of fungal pathogens on behavioural traits that are crucial for colony functioning, such as guarding behaviour. Here, we evaluated the effect of Beauveria bassiana on the sophisticated kin recognition system of Tetragonisca angustula, a bee with morphologically specialized entrance guards. By combining behavioural assays and chemical analyses, we show that guards detect pathogen-exposed nestmates, preventing them from accessing nests. Furthermore, cuticular profiles of pathogen-exposed foragers contained significantly lower amounts of linear alkanes than the unexposed ones. Such chemical cues associated with fungal conidia may potentially trigger aggression towards pathogen-exposed bees, preventing pathogen spread into and among colonies. This is the first demonstration that this highly abundant native bee seems to respond in a much more adaptive way to a potentially infectious threat, outweighing the costs of losing foraging workforce when reducing the chances of fungal pathogen outbreaks within their colonies, than honeybees do.
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Affiliation(s)
- Felipe Chagas Rocha Almeida
- Laboratory of Chemical Ecology and Insect Behaviour, Department of Entomology and Acarology, Luiz de Queiroz College of Agriculture, University of São Paulo, Piracicaba, Brazil
| | - Diego Martins Magalhães
- Laboratory of Chemical Ecology and Insect Behaviour, Department of Entomology and Acarology, Luiz de Queiroz College of Agriculture, University of São Paulo, Piracicaba, Brazil
| | - Arodí Prado Favaris
- Laboratory of Chemical Ecology and Insect Behaviour, Department of Entomology and Acarology, Luiz de Queiroz College of Agriculture, University of São Paulo, Piracicaba, Brazil
| | - Jonathan Rodríguez
- Laboratory of Pathology and Microbial Control, Department of Entomology and Acarology, Luiz de Queiroz College of Agriculture, University of São Paulo, Piracicaba, Brazil
| | - Kamila Emmanuella Xavier Azevedo
- Laboratory of Chemical Ecology and Insect Behaviour, Department of Entomology and Acarology, Luiz de Queiroz College of Agriculture, University of São Paulo, Piracicaba, Brazil
| | - José Maurício Simões Bento
- Laboratory of Chemical Ecology and Insect Behaviour, Department of Entomology and Acarology, Luiz de Queiroz College of Agriculture, University of São Paulo, Piracicaba, Brazil
| | - Denise Araujo Alves
- Laboratory of Chemical Ecology and Insect Behaviour, Department of Entomology and Acarology, Luiz de Queiroz College of Agriculture, University of São Paulo, Piracicaba, Brazil.
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Baudier KM, Bennett MM, Barrett M, Cossio FJ, Wu RD, O'Donnell S, Pavlic TP, Fewell JH. Soldier neural architecture is temporarily modality-specialized but poorly predicted by repertoire size in the stingless bee Tetragonisca angustula. J Comp Neurol 2021; 530:672-682. [PMID: 34773646 DOI: 10.1002/cne.25273] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2021] [Revised: 10/21/2021] [Accepted: 10/26/2021] [Indexed: 11/09/2022]
Abstract
Individual heterogeneity within societies provides opportunities to test hypotheses about adaptive neural investment in the context of group cooperation. Here we explore neural investment in defense specialist soldiers of the eusocial stingless bee (Tetragonisca angustula) which are age sub-specialized on distinct defense tasks and have an overall higher lifetime task repertoire than other sterile workers within the colony. Consistent with predicted behavioral demands, soldiers had higher relative visual (optic lobe) investment than non-soldiers but only during the period when they were performing the most visually demanding defense task (hovering guarding). As soldiers aged into the less visually demanding task of standing guarding this difference disappeared. Neural investment was otherwise similar across all colony members. Despite having larger task repertoires, soldiers had similar absolute brain size and smaller relative brain size compared to other workers, meaning that lifetime task repertoire size was a poor predictor of brain size. Both high behavioral specialization in stable environmental conditions and reassignment across task groups during a crisis occur in T. angustula. The differences in neurobiology we report here are consistent with these specialized but flexible defense strategies. This work broadens our understanding of how neurobiology mediates age and morphological task specialization in highly cooperative societies. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Kaitlin M Baudier
- School of Biological, Environmental and Earth Sciences, The University of Southern Mississippi, Hattiesburg, MS, USA.,School of Life Sciences, Social Insect Research Group, Arizona State University, Tempe, AZ, USA
| | - Meghan M Bennett
- School of Life Sciences, Social Insect Research Group, Arizona State University, Tempe, AZ, USA.,USDA-ARS Carl Hayden Bee Research Center, Tucson, AZ, USA
| | - Meghan Barrett
- Department of Biology, Drexel University, Philadelphia, PA, USA
| | - Frank J Cossio
- School of Life Sciences, Social Insect Research Group, Arizona State University, Tempe, AZ, USA
| | - Robert D Wu
- School of Life Sciences, Social Insect Research Group, Arizona State University, Tempe, AZ, USA
| | - Sean O'Donnell
- Department of Biology, Drexel University, Philadelphia, PA, USA.,Department of Biodiversity, Earth and Environmental Science, Drexel University, Philadelphia, PA, USA
| | - Theodore P Pavlic
- School of Life Sciences, Social Insect Research Group, Arizona State University, Tempe, AZ, USA.,School of Computing, Informatics, and Decision Systems Engineering, Arizona State University, Tempe, AZ, USA.,School of Sustainability, Arizona State University, Tempe, AZ, USA.,School of Complex Adaptive Systems, Arizona State University, Tempe, AZ, USA
| | - Jennifer H Fewell
- School of Life Sciences, Social Insect Research Group, Arizona State University, Tempe, AZ, USA
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Barrs KR, Ani MO, Eversman KK, Rowell JT, Wagoner KM, Rueppell O. Time-accuracy trade-off and task partitioning of hygienic behavior among honey bee (Apis mellifera) workers. Behav Ecol Sociobiol 2021. [DOI: 10.1007/s00265-020-02940-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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14
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Wagner T, Bachenberg L, Glaser SM, Oikonomou A, Linn M, Grüter C. Large body size variation is associated with low communication success in tandem running ants. Behav Ecol Sociobiol 2020. [DOI: 10.1007/s00265-020-02941-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Abstract
Diversity in animal groups is often assumed to increase group performance. In insect colonies, genetic, behavioural and morphological variation among workers can improve colony functioning and resilience. However, it has been hypothesized that during communication processes, differences between workers, e.g. in body size, could also have negative effects. Tandem running is a common recruitment strategy in ants and allows a leader to guide a nestmate follower to resources. A substantial proportion of tandem runs fail because leader and follower lose contact. Using the ant Temnothorax nylanderi as a model system, we tested the hypothesis that tandem running success is impaired if leader and follower differ in size. Indeed, we found that the success rate of tandem pairs drops considerably as size variation increases: tandem runs were unsuccessful when the leader–follower size difference exceeded 10%, whereas ~ 80% of tandem runs were successful when ants differed less than 5% in body length. Possible explanations are that size differences are linked to differences in walking speed or sensory perception. Ants did not choose partners of similar size, but extranidal workers were larger than intranidal workers, which could reduce recruitment mistakes because it reduced the chance that very large and very small ants perform tandem runs together. Our results suggest that phenotypic differences between interacting workers can have negative effects on the efficiency of communication processes. Whether phenotypic variation has positive or negative effects is likely to depend on the task and the phenotypic trait that shows variation.
Significance statement
Diversity is often assumed to increase colony performance in social insects. However, phenotypic differences among workers could also have negative effects, e.g. during communication. Tandem running is a common recruitment strategy in ants, but tandem runs often fail when ants lose contact. We used the ant Temnothorax nylanderi to test the hypothesis that body size differences between tandem leader and follower impair tandem communication. We show that the success rate of tandem pairs drops considerably as size variation increases, possibly because ants of varying size also differ in walking speed. Our study supports the hypothesis that phenotypic variation among workers might not always be beneficial and can negatively impact the efficiency of communication processes.
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Baudier KM, Bennett MM, Ostwald MM, Hart S, Pavlic TP, Fewell JH. Age-based changes in kairomone response mediate task partitioning in stingless bee soldiers (Tetragonisca angustula). Behav Ecol Sociobiol 2020. [DOI: 10.1007/s00265-020-02902-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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16
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Balbuena MS, Farina WM. Chemosensory reception in the stingless bee Tetragonisca angustula. JOURNAL OF INSECT PHYSIOLOGY 2020; 125:104076. [PMID: 32593653 DOI: 10.1016/j.jinsphys.2020.104076] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/10/2019] [Revised: 06/11/2020] [Accepted: 06/12/2020] [Indexed: 06/11/2023]
Abstract
In stingless bees, unlike honey bees, the relationship between chemosensory abilities and colony labor division has been poorly studied. Here we examined odor reception and gustatory responsiveness of the stingless bee Tetragonisca angustula focusing on workers, whose are involved in different tasks. Using the proboscis extension response, we studied sucrose response thresholds (SRTs) of foragers and guards. Peripheral responses to odors at the antennae were recorded by electroantennography (EAG). Additionally, we quantified and described the number and type of sensilla present on the antennae using scanning electron microscopy. Foragers' SRTs changed according to the resource collected: nonpollen foragers showed higher SRTs than pollen foragers and guards, that showed similar sucrose responsiveness. EAG signal strength of both foragers and guards increased with increasing odor concentration. Interestingly, guard bees showed the highest response to citral, an odor that triggers defensive behavior in T. angustula. Type and number of sensilla present in the antennae of guards and foragers were similar. Our results suggest that differences found in chemosensory responses among worker subcastes are task dependent.
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Affiliation(s)
- María Sol Balbuena
- Laboratorio de Insectos Sociales, Departamento de Biodiversidad y Biología Experimental, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina; Instituto de Fisiología, Biología Molecular y Neurociencias (IFIBYNE), CONICET, Universidad de Buenos Aires, Buenos Aires, Argentina.
| | - Walter M Farina
- Laboratorio de Insectos Sociales, Departamento de Biodiversidad y Biología Experimental, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina; Instituto de Fisiología, Biología Molecular y Neurociencias (IFIBYNE), CONICET, Universidad de Buenos Aires, Buenos Aires, Argentina
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