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Lagos-Oviedo JJ, Pen I, Kreider JJ. Coevolution of larval signalling and worker response can trigger developmental caste determination in social insects. Proc Biol Sci 2024; 291:20240538. [PMID: 39013422 PMCID: PMC11251759 DOI: 10.1098/rspb.2024.0538] [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: 03/05/2024] [Accepted: 05/23/2024] [Indexed: 07/18/2024] Open
Abstract
Eusocial insects belong to distinct queen and worker castes, which, in turn, can be divided into several morphologically specialized castes of workers. Caste determination typically occurs by differential nutrition of developing larvae. We present a model for the coevolution of larval signalling and worker task allocation-both modelled by flexible smooth reaction norms-to investigate the evolution of caste determination mechanisms and worker polymorphism. In our model, larvae evolve to signal their nutritional state to workers. The workers evolve to allocate time to foraging for resources versus feeding the brood, conditional on the larval signals and their body size. Worker polymorphism evolves under accelerating foraging returns of increasing body size, which causes selection to favour large foraging and small nursing workers. Worker castes emerge because larvae evolve to amplify their signals after obtaining some food, which causes them to receive more food, while the other larvae remain unfed. This leads to symmetry-breaking among the larvae, which are either well-nourished or malnourished, thus emerging as small or large workers. Our model demonstrates the evolution of nutrition-dependent caste determination and worker polymorphism by a self-reinforcement mechanism that evolves from the interplay of larval signalling and worker response to the signals.
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Affiliation(s)
- Juan J. Lagos-Oviedo
- Theoretical Research in Evolutionary Life Sciences, Groningen Institute for Evolutionary Life Sciences, University of Groningen, Nijenborgh 7, Groningen 9747 AG, The Netherlands
- Department of Animal Ecology and Tropical Biology, University of Würzburg, Am Hubland, Würzburg 97074, Germany
| | - Ido Pen
- Theoretical Research in Evolutionary Life Sciences, Groningen Institute for Evolutionary Life Sciences, University of Groningen, Nijenborgh 7, Groningen 9747 AG, The Netherlands
| | - Jan J. Kreider
- Theoretical Research in Evolutionary Life Sciences, Groningen Institute for Evolutionary Life Sciences, University of Groningen, Nijenborgh 7, Groningen 9747 AG, The Netherlands
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2
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Gilgenreiner M, Kurze C. Age dominates flight distance and duration, while body size shapes flight speed in Bombus terrestris L. (Hymenoptera: Apidae). Proc Biol Sci 2024; 291:20241001. [PMID: 39079662 PMCID: PMC11288671 DOI: 10.1098/rspb.2024.1001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2024] [Revised: 06/04/2024] [Accepted: 06/05/2024] [Indexed: 08/03/2024] Open
Abstract
Flight plays a crucial role in the fitness of insect pollinators, such as bumblebees. Despite their relatively large body size compared with their wings, bumblebees can fly under difficult ambient conditions, such as cooler temperatures. While their body size is often positively linked to their foraging range and flight ability, the influence of age remains less explored. Here, we studied the flight performance (distance, duration and speed) of ageing bumblebee workers using tethered flight mills. Additionally, we measured their intertegular distance and dry mass as proxies for their body size. We found that the flight distance and duration were predominantly influenced by age, challenging assumptions that age does not play a key role in foraging and task allocation. From the age of 7 to 14 days, flight distance and duration increased sixfold and fivefold, respectively. Conversely, the body size primarily impacted the maximum and average flight speed of workers. Our findings indicate that age substantially influences the flight distance and duration in bumblebee workers, affecting foraging performance and potentially altering task allocation strategies. This underscores the importance of considering individual age and physiological changes alongside body size/mass in experiments involving bumblebee workers.
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Affiliation(s)
- Milena Gilgenreiner
- Institute for Zoology and Evolutionary Biology, University of Regensburg, Regensburg, Germany
| | - Christoph Kurze
- Institute for Zoology and Evolutionary Biology, University of Regensburg, Regensburg, Germany
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3
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Klunk CL, Argenta MA, Rosumek FB, Schmelzle S, van de Kamp T, Hammel JU, Pie MR, Heethoff M. Simulated biomechanical performance of morphologically disparate ant mandibles under bite loading. Sci Rep 2023; 13:16833. [PMID: 37803099 PMCID: PMC10558566 DOI: 10.1038/s41598-023-43944-8] [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: 07/21/2023] [Accepted: 09/30/2023] [Indexed: 10/08/2023] Open
Abstract
Insects evolved various modifications to their mouthparts, allowing for a broad exploration of feeding modes. In ants, workers perform non-reproductive tasks like excavation, food processing, and juvenile care, relying heavily on their mandibles. Given the importance of biting for ant workers and the significant mandible morphological diversity across species, it is essential to understand how mandible shape influences its mechanical responses to bite loading. We employed Finite Element Analysis to simulate biting scenarios on mandible volumetric models from 25 ant species classified in different feeding habits. We hypothesize that mandibles of predatory ants, especially trap-jaw ants, would perform better than mandibles of omnivorous species due to their necessity to subdue living prey. We defined simulations to allow only variation in mandible morphology between specimens. Our results demonstrated interspecific differences in mandible mechanical responses to biting loading. However, we found no evident differences in biting performance between the predatory and the remaining ants, and trap-jaw mandibles did not show lower stress levels than other mandibles under bite loading. These results suggest that ant feeding habit is not a robust predictor of mandible biting performance, a possible consequence of mandibles being employed as versatile tools to perform several tasks.
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Affiliation(s)
- C L Klunk
- Graduate Program in Ecology and Conservation, Universidade Federal do Paraná, Centro Politécnico, Av. Cel. Francisco H. dos Santos, 100 - Jardim das Américas, Curitiba, PR, 81531-980, Brazil.
- Animal Evolutionary Ecology, Technische Universität Darmstadt, Schnittspahnstr. 3, 64287, Darmstadt, Germany.
| | - M A Argenta
- Department of Civil Construction, Universidade Federal do Paraná, Curitiba, PR, Brazil
| | - F B Rosumek
- Department of Ecology and Zoology, Universidade Federal de Santa Catarina, Florianópolis, SC, Brazil
| | - S Schmelzle
- Animal Evolutionary Ecology, Technische Universität Darmstadt, Schnittspahnstr. 3, 64287, Darmstadt, Germany
| | - T van de Kamp
- Institute for Photon Science and Synchrotron Radiation (IPS), Karlsruhe Institute of Technology (KIT), Eggenstein-Leopoldshafen, Germany
- Laboratory for Applications of Synchrotron Radiation (LAS), Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany
| | - J U Hammel
- Institute of Materials Physics, Helmholtz-Zentrum Hereon, Geesthacht, Germany
| | - M R Pie
- Biology Department, Edge Hill University, Ormskirk, Lancashire, UK
| | - M Heethoff
- Animal Evolutionary Ecology, Technische Universität Darmstadt, Schnittspahnstr. 3, 64287, Darmstadt, Germany.
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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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5
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Dziechciarz P, Strachecka A, Borsuk G, Olszewski K. Workers of Apis mellifera Reared in Small-Cell Combs Show Higher Activity of the Proteolytic System in Hemolymph than Workers Reared in Standard-Cell Combs in Laboratory Cage Tests. Animals (Basel) 2023; 13:ani13081368. [PMID: 37106931 PMCID: PMC10135212 DOI: 10.3390/ani13081368] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2023] [Revised: 04/13/2023] [Accepted: 04/14/2023] [Indexed: 04/29/2023] Open
Abstract
The aim of the study was to compare the activities of proteases and their inhibitors in the hemolymph of honeybee workers reared in small-cell combs (SMC) and standard-cell combs (STC) in laboratory cage tests. The analyses conducted in laboratory conditions facilitated assessment of the impact of the comb cell width (small vs. standard) along with eliminating the influence of many environmental factors on the results. The width of the comb cells in which the workers were reared had a significant effect on the protein concentrations and proteolytic system activities in the hemolymph. Irrespective of the age of the workers, higher protein concentrations were found in the hemolymph of the SMC workers. In turn, the activities of proteases and their inhibitors in the hemolymph of 1-day-old bees were higher in the STC workers. In older bees, aged 7-21 days, activity was higher in the SMC workers. The role of the considerable cell width variability in natural combs that were built without the use of an artificially produced wax foundation is worth investigating. It is highly probable that the impact of the comb cell width on the features of workers reared in these combs modifies the age polyethism in the worker caste as well. The investigation results of one-season studies of honeybees could be seriously affected by random factors. To reduce the risk of these effects, it is advisable to continue experiments over a few consecutive years.
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Affiliation(s)
- Piotr Dziechciarz
- Subdepartment of Apidology, Institute of Biological Basis of Animal Production, Faculty of Animal Sciences and Bioeconomy, University of Life Sciences in Lublin, 20-950 Lublin, Poland
| | - Aneta Strachecka
- Department of Invertebrate Ecophysiology and Experimental Biology, University of Life Sciences in Lublin, 20-950 Lublin, Poland
| | - Grzegorz Borsuk
- Subdepartment of Apidology, Institute of Biological Basis of Animal Production, Faculty of Animal Sciences and Bioeconomy, University of Life Sciences in Lublin, 20-950 Lublin, Poland
| | - Krzysztof Olszewski
- Subdepartment of Apidology, Institute of Biological Basis of Animal Production, Faculty of Animal Sciences and Bioeconomy, University of Life Sciences in Lublin, 20-950 Lublin, Poland
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6
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Climate and body size have differential roles on melanism evolution across workers in a worldwide ant genus. Oecologia 2022; 199:579-587. [PMID: 35804249 DOI: 10.1007/s00442-022-05211-x] [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: 11/19/2021] [Accepted: 06/14/2022] [Indexed: 10/17/2022]
Abstract
One of the main aspects associated with the diversity in animal colour is the variation in melanization levels. In ectotherms, melanism can be advantageous in aiding thermoregulation through heat absorption. Darker bodies may also serve as a shield from harmful UV-B radiation. Melanism may also confer protection against parasites and predators through improving immunity responses and camouflage in regions with high precipitation, with complex and shaded vegetations and greater diversity of pathogens and parasites. We studied melanism evolution in the globally distributed ant genus Pheidole under the pressures of temperature, UV-B radiation and precipitation, while considering the effects of body size and nest habit, traits that are commonly overlooked. More importantly, we account for worker caste polymorphism, which is marked by distinct roles and behaviours. We revealed for the first time distinct evolutionary trajectories for each worker subcaste. As expected, major workers from species inhabiting locations with lower temperatures and higher precipitation tend to be more melanised. Curiously, we show a slight trend where minor workers of larger species also tend to have darker bodies when inhabiting regions with higher precipitation. Lastly, we did not find evidence for the effects of UV-B radiation and nest habit in the lightness variation of workers. Our paper explores the evolution of ant melanization considering a marked ant worker polymorphism and a wide range of ecological factors. We discuss our findings under the light of the Thermal Melanism Hypothesis, the Photoprotection Hypothesis and the Gloger's Rule.
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GUERRERO ROBERTOJ, GARCÍA EMIRA, FERNÁNDEZ FERNANDO. The Pheidole Westwood, 1839 ants (Formicidae: Myrmicinae) in Colombia: new records including two species with remarkable morphology. Zootaxa 2022; 5154:319-332. [DOI: 10.11646/zootaxa.5154.3.5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2022] [Indexed: 11/04/2022]
Abstract
Pheidole is one of the most diverse groups of ants in the World, with more than 630 species known from the Neotropical Region. As part of studies on the ant fauna of Colombia, a contribution to the taxonomy of these ants is presented here. The worker subcastes of Pheidole praeusta Roger are redescribed, this being the first record of a trimorphic species outside the Nearctic region. Pheidole amata Forel is proposed as a junior synonym of Pheidole praeusta. Pheidole rogeripolita Longino is identified as the first species in the New World with a 5-segmented antennal club, and the third species with such antennal club in the world. Pheidole distorta Forel, a species described 120 years ago, is redescribed, and notes on its reproductive caste are offered. The description and diagnosis of the Pheidole iceni Fernández soldier is amended. New species records for the country and South America are listed. Multifocus photographs of P. praeusta, and P. rogeripolita are offered.
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8
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Casadei‐Ferreira A, Feitosa RM, Pie MR. Size and shape in the evolution of the worker head in
Pheidole
ants (Hymenoptera: Formicidae). J Zool (1987) 2022. [DOI: 10.1111/jzo.12978] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- A. Casadei‐Ferreira
- Departamento de Zoologia Setor de Ciências Biológicas Centro Politécnico Universidade Federal do Paraná Curitiba Paraná Brazil
- Biodiversity and Biocomplexity Unit Okinawa Institute of Science and Technology Graduate University Onna Okinawa Japan
| | - R. M. Feitosa
- Departamento de Zoologia Setor de Ciências Biológicas Centro Politécnico Universidade Federal do Paraná Curitiba Paraná Brazil
| | - M. R. Pie
- Departamento de Zoologia Setor de Ciências Biológicas Centro Politécnico Universidade Federal do Paraná Curitiba Paraná Brazil
- Biology Department Edge Hill University Ormskirk Lancashire UK
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9
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Dziechciarz P, Strachecka A, Olszewski K. Effect of Comb Cell Width on the Activity of the Proteolytic System in the Hemolymph of Apis mellifera Workers. Animals (Basel) 2022; 12:ani12080978. [PMID: 35454226 PMCID: PMC9030460 DOI: 10.3390/ani12080978] [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: 03/16/2022] [Revised: 04/05/2022] [Accepted: 04/08/2022] [Indexed: 02/04/2023] Open
Abstract
Simple Summary Honeybees are threatened by many biotic factors, e.g., microbes and parasites such as Nosema spp. and Varroa mites, or predators, as well as environmental factors such as weather conditions, pesticides, or food contaminants. Honeybee colonies have behavioral defense mechanisms against pathogens resulting from their social lifestyle. Moreover, these insects have innate immune barriers. One of the immune defense elements is the proteolytic system consisting of proteases and their inhibitors in the hemolymph (insect blood) and on the body surface. The proteolytic system is activated by both external and internal environmental factors. An important element of the nest environment is the comb. In feral bee colony nests, the bee comb cell size varies in width. In turn, bee colonies in Europe tend to be kept only on standard- (cell width approx. 5.50 mm) or small-cell (cell width approx. 4.90 mm) combs. We assessed the proteolytic system activity in the hemolymph of workers reared in a small-cell comb and a standard-cell comb in colonies kept simultaneously on standard- and small-cell combs. Simultaneous keeping of a colony on standard- and small-cell combs is a novel approach to the use of small-cell combs in beekeeping. The width of comb cells (small or standard) where workers were reared had a significant effect on the protein concentrations and the activities of proteases and protease inhibitors in hemolymph of workers. The protein concentrations in 1-day-old workers were higher in bees reared in small-cell combs than in those reared in standard-cell combs. The opposite was found in the groups of older bees (aged 7, 14 and 21 d). Moreover, the activities of proteases and their inhibitors in 1-day-old workers were always higher in bees reared in standard-cell combs, whereas opposite results were usually obtained in the group of the older workers. The differences between workers reared in the small-cell combs and those from the standard-cell combs may be associated with their different tasks. Workers reared in small-cell combs probably work outside the nest as foragers, whereas those reared in standard-cell combs work in the nest. However, this assumption requires confirmation. Abstract This study is a continuation of the innovative research of the impact of rearing of bee colonies simultaneously on standard- and small-cell combs on the traits of worker bees and bee colonies. Its aim was to compare the activities of proteases and their inhibitors in the hemolymph of workers reared in a small-cell comb (SMC) and a standard-cell comb (STC) in colonies kept simultaneously on standard- and small-cell combs. The width of comb cells in which workers are reared has a significant effect on the protein concentration and the proteolytic system in the hemolymph, which is reflected in the activities of proteases and their inhibitors. The protein concentrations in the 1-day-old workers were always higher (p ≤ 0.05) in the SMC than STC workers. The opposite was found in the older bee workers (aged 7, 14 and 21 d). The activities of proteases and their inhibitors in the 1-day-old workers were always higher (usually significantly at p ≤ 0.05) in STC than SMC workers, and opposite results were observed in the groups of the older workers (aged 7, 14 and 21 d). The differences between the workers from small-cell combs and those reared in standard-cell combs may be related to their different tasks. Workers reared in small-cell combs probably work as foragers outside the nest, whereas bees reared in standard-cell combs work in the nest. This hypothesis requires confirmation. To reduce the impact of accidental determinants on the results of single-season research on honeybees, it is advisable that such investigations should be conducted for several consecutive years.
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Affiliation(s)
- Piotr Dziechciarz
- Department of Apidology, Institute of Biological Basis of Animal Production, Faculty of Animal Sciences and Bioeconomy, University of Life Sciences in Lublin, 20-950 Lublin, Poland;
- Correspondence:
| | - Aneta Strachecka
- Department of Invertebrate Ecophysiology and Experimental Biology, University of Life Sciences in Lublin, 20-950 Lublin, Poland;
| | - Krzysztof Olszewski
- Department of Apidology, Institute of Biological Basis of Animal Production, Faculty of Animal Sciences and Bioeconomy, University of Life Sciences in Lublin, 20-950 Lublin, Poland;
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10
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Jeanne RL, Loope KJ, Bouwma AM, Nordheim EV, Smith ML. Five decades of misunderstanding in the social Hymenoptera: a review and meta-analysis of Michener's paradox. Biol Rev Camb Philos Soc 2022; 97:1559-1611. [PMID: 35338566 PMCID: PMC9546470 DOI: 10.1111/brv.12854] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2019] [Revised: 03/15/2022] [Accepted: 03/17/2022] [Indexed: 12/22/2022]
Abstract
In a much-cited 1964 paper entitled "Reproductive efficiency in relation to colony size in hymenopterous societies," Charles Michener investigated the correlation between a colony's size and its reproductive efficiency - the ability of its adult females to produce reproductives, measured as per-capita output. Based on his analysis of published data from destructively sampled colonies in 18 species, he reported that in most of these species efficiency decreased with increasing colony size. His conclusion that efficiency is higher in smaller groups has since gained widespread acceptance. But it created a seeming paradox: how can natural selection maintain social behaviour when a female apparently enjoys her highest per-capita output by working alone? Here we treat Michener's pattern as a hypothesis and perform the first large-scale test of its prediction across the eusocial Hymenoptera. Because data on actual output of reproductives were not available for most species, Michener used various proxies, such as nest size, numbers of brood, or amounts of stored food. We show that for each of Michener's data sets the reported decline in per-capita productivity can be explained by factors other than decreasing efficiency, calling into question his conclusion that declining efficiency is the cause of the pattern. The most prominent cause of bias is the failure of the proxy to capture all forms of output in which the colony invests during the course of its ontogeny. Other biasing factors include seasonal effects and a variety of methodological flaws in the data sets he used. We then summarize the results of 215 data sets drawn from post-1964 studies of 80 species in 33 genera that better control for these factors. Of these, 163 data sets are included in two meta-analyses that statistically synthesize the available data on the relationship between colony size and efficiency, accounting for variable sample sizes and non-independence among the data sets. The overall effect, and those for most taxonomic subgroups, indicates no loss of efficiency with increasing colony size. Two exceptional taxa, the halictid bees and independent-founding paper wasps, show negative trends consistent with the Michener hypothesis in some species. We conclude that in most species, particularly those with large colony sizes, the hypothesis of decreasing efficiency with increasing colony size is not supported. Finally, we explore potential mechanisms through which the level of efficiency can decrease, be maintained, or even increase, as colonies increase in size.
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Affiliation(s)
- Robert L Jeanne
- Department of Entomology, University of Wisconsin, 1630 Linden Drive, Madison, WI, 53706, U.S.A
| | - Kevin J Loope
- Department of Fish and Wildlife Conservation, Virginia Polytechnic Institute and State University (Virginia Tech), Cheatham Hall, 310 W. Campus Drive, Blacksburg, VA, 24060, U.S.A
| | - Andrew M Bouwma
- Department of Integrative Biology, Oregon State University, Cordley Hall, 3029, 2701 SW Campus Way, Corvallis, OR, 97331, U.S.A
| | - Erik V Nordheim
- Department of Statistics, University of Wisconsin, 1300 University Avenue, Madison, WI, 53706, U.S.A
| | - Michael L Smith
- Department of Biological Sciences, Auburn University, Auburn, AL, 36849, U.S.A
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11
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Hu J, Zhan R, Wu H, Li Y. Wolf Pack's Role Matching Labor Division Model for Dynamic Task Allocation of Swarm Robotics. INTERNATIONAL JOURNAL OF SWARM INTELLIGENCE RESEARCH 2022. [DOI: 10.4018/ijsir.310063] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
First, through in-depth analysis of the diversified collective behaviors in wolf pack, this study summarizes four remarkable features of wolf pack's labor division. Second, the wolf pack's role-task matching labor division mechanism is investigated, namely the individual wolves perform specific tasks that match their respective roles, and then a novel role matching labor division model is proposed. Finally, the performances of RMM are tested and evaluated with two swarm robotics task allocation scenarios. It is proved that RMM has higher solving efficiency and faster calculation speed for the concerned problem than the compared approach. Moreover, the proposed model shows advantages in the task allocation balance, robustness, and real time, especially in the dynamic response capability to the complex and changing environments.
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Affiliation(s)
- Jinqiang Hu
- Armed Police Force Engineering University, China
| | - Renjun Zhan
- Armed Police Force Engineering University, China
| | - Husheng Wu
- Armed Police Force Engineering University, China
| | - Yongli Li
- Armed Police Force Engineering University, China
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12
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Strachecka A, Migdał P, Kuszewska K, Skowronek P, Grabowski M, Paleolog J, Woyciechowski M. Humoral and Cellular Defense Mechanisms in Rebel Workers of Apis mellifera. BIOLOGY 2021; 10:1146. [PMID: 34827139 PMCID: PMC8615136 DOI: 10.3390/biology10111146] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/12/2021] [Revised: 11/03/2021] [Accepted: 11/03/2021] [Indexed: 12/20/2022]
Abstract
The physiological state of an insect depends on efficiently functioning immune mechanisms such as cellular and humoral defenses. However, compounds participating in these mechanisms also regulate reproductive caste formation and are responsible for reproductive division of labor as well as for labor division in sterile workers. Divergent reaction of the same genotype yielding reproductive queens and worker castes led to shaping of the physiological and behavioral plasticity of sterile or reproductive workers. Rebels that can lay eggs while maintaining tasks inside and outside the colony exhibit both queen and worker traits. So, we expected that the phagocytic index, JH3 titer, and Vg concentration would be higher in rebels than in normal workers and would increase with their age. We also assumed that the numbers of oenocytes and their sizes would be greater in rebels than in normal workers. The rebels and the normal workers were collected at the age of 1, 7, 14, and 21 days, respectively. Hemolymph and fat bodies were collected for biochemical and morphological analyses. The high levels of JH, Vg, and the phagocytic index, as well as increased numbers and sizes of oenocytes in the fat body cells demonstrate the physiological and phenotypic adaptation of rebels to the eusocial life of honeybees.
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Affiliation(s)
- Aneta Strachecka
- Department of Invertebrate Ecophysiology and Experimental Biology, University of Life Sciences in Lublin, 20-950 Lublin, Poland; (P.S.); (M.G.); (J.P.)
| | - Paweł Migdał
- Department of Environment, Hygiene and Animal Welfare, Wroclaw University of Environmental and Life Sciences, 50-375 Wroclaw, Poland;
| | - Karolina Kuszewska
- Institute of Environmental Sciences, Jagiellonian University, 30-387 Krakow, Poland; (K.K.); (M.W.)
| | - Patrycja Skowronek
- Department of Invertebrate Ecophysiology and Experimental Biology, University of Life Sciences in Lublin, 20-950 Lublin, Poland; (P.S.); (M.G.); (J.P.)
| | - Marcin Grabowski
- Department of Invertebrate Ecophysiology and Experimental Biology, University of Life Sciences in Lublin, 20-950 Lublin, Poland; (P.S.); (M.G.); (J.P.)
| | - Jerzy Paleolog
- Department of Invertebrate Ecophysiology and Experimental Biology, University of Life Sciences in Lublin, 20-950 Lublin, Poland; (P.S.); (M.G.); (J.P.)
| | - Michał Woyciechowski
- Institute of Environmental Sciences, Jagiellonian University, 30-387 Krakow, Poland; (K.K.); (M.W.)
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13
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Koch S, Tahara R, Vasquez-Correa A, Abouheif E. Nano-CT imaging of larvae in the ant Pheidole hyatti reveals coordinated growth of a rudimentary organ necessary for soldier development. JOURNAL OF EXPERIMENTAL ZOOLOGY PART B-MOLECULAR AND DEVELOPMENTAL EVOLUTION 2021; 336:540-553. [PMID: 34549874 DOI: 10.1002/jez.b.23097] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/06/2021] [Revised: 08/05/2021] [Accepted: 09/02/2021] [Indexed: 11/09/2022]
Abstract
The growth of imaginal discs in holometabolous insects is coordinated with larval growth to ensure the symmetrical and proportional development of the adult appendages. In ants, the differential growth of these discs generates distinct castes-the winged male and queen castes and the wingless worker caste. In the hyperdiverse ant genus Pheidole, the worker caste is composed of two morphologically distinct subcastes: small-headed minor workers and larger, big-headed, soldiers. Although these worker subcastes are completely wingless, soldier larvae develop rudimentary forewing discs that function in generating the disproportionate head-to-body scaling and size of soldiers. It remains unclear, however, how rudimentary forewing discs in soldier larvae are coordinated with other imaginal discs. Here we show, using quantitative nano-CT imaging and three-dimensional analyses, that the increase in the volume of the soldier rudimentary forewing discs is coordinated with larval size as well as with the increase in the volume of the leg and eye-antennal (head) discs. However, relative to larval size, we found that when the rudimentary forewing discs appear during the last larval instar, they are relatively smaller but increase in volume faster than that of the head (eye-antennal) and leg discs. These findings show that the rudimentary wing disc in soldier larvae has evolved novel patterns of inter-organ coordination as compared with other insects to generate the big-headed soldier caste in Pheidole. More generally, our study raises the possibility that novel patterns of inter-organ coordination are a general feature of rudimentary organs that acquire novel regulatory functions during development and evolution.
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Affiliation(s)
- Sophie Koch
- Department of Biology, McGill University, Montréal, Quebec, Canada
| | - Rui Tahara
- Department of Biology, McGill University, Montréal, Quebec, Canada
| | | | - Ehab Abouheif
- Department of Biology, McGill University, Montréal, Quebec, Canada
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14
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Ulrich Y, Kawakatsu M, Tokita CK, Saragosti J, Chandra V, Tarnita CE, Kronauer DJC. Response thresholds alone cannot explain empirical patterns of division of labor in social insects. PLoS Biol 2021; 19:e3001269. [PMID: 34138839 PMCID: PMC8211278 DOI: 10.1371/journal.pbio.3001269] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2020] [Accepted: 05/07/2021] [Indexed: 12/30/2022] Open
Abstract
The effects of heterogeneity in group composition remain a major hurdle to our understanding of collective behavior across disciplines. In social insects, division of labor (DOL) is an emergent, colony-level trait thought to depend on colony composition. Theoretically, behavioral response threshold models have most commonly been employed to investigate the impact of heterogeneity on DOL. However, empirical studies that systematically test their predictions are lacking because they require control over colony composition and the ability to monitor individual behavior in groups, both of which are challenging. Here, we employ automated behavioral tracking in 120 colonies of the clonal raider ant with unparalleled control over genetic, morphological, and demographic composition. We find that each of these sources of variation in colony composition generates a distinct pattern of behavioral organization, ranging from the amplification to the dampening of inherent behavioral differences in heterogeneous colonies. Furthermore, larvae modulate interactions between adults, exacerbating the apparent complexity. Models based on threshold variation alone only partially recapitulate these empirical patterns. However, by incorporating the potential for variability in task efficiency among adults and task demand among larvae, we account for all the observed phenomena. Our findings highlight the significance of previously overlooked parameters pertaining to both larvae and workers, allow the formulation of theoretical predictions for increasing colony complexity, and suggest new avenues of empirical study. This study uses automated tracking of clonal raider ants and mathematical modeling to reveal how previously overlooked traits of larvae and workers might shape social organization in heterogeneous ant colonies. By incorporating the potential for variability in task efficiency among adults and task demand among larvae, the authors were able to account for all empirically observed phenomena.
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Affiliation(s)
- Yuko Ulrich
- Laboratory of Social Evolution and Behavior, The Rockefeller University, New York, New York, United States of America
- Institute of Integrative Biology, ETH Zurich, Zurich, Switzerland
| | - Mari Kawakatsu
- Program in Applied and Computational Mathematics, Princeton University, Princeton, New Jersey, United States of America
| | - Christopher K. Tokita
- Department of Ecology and Evolutionary Biology, Princeton University, Princeton, New Jersey, United States of America
| | - Jonathan Saragosti
- Laboratory of Social Evolution and Behavior, The Rockefeller University, New York, New York, United States of America
| | - Vikram Chandra
- Laboratory of Social Evolution and Behavior, The Rockefeller University, New York, New York, United States of America
| | - Corina E. Tarnita
- Department of Ecology and Evolutionary Biology, Princeton University, Princeton, New Jersey, United States of America
- * E-mail: (CET); (DJCK)
| | - Daniel J. C. Kronauer
- Laboratory of Social Evolution and Behavior, The Rockefeller University, New York, New York, United States of America
- * E-mail: (CET); (DJCK)
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15
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Klunk CL, Argenta MA, Casadei-Ferreira A, Economo EP, Pie MR. Mandibular morphology, task specialization and bite mechanics in Pheidole ants (Hymenoptera: Formicidae). J R Soc Interface 2021; 18:20210318. [PMID: 34102082 PMCID: PMC8187013 DOI: 10.1098/rsif.2021.0318] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2021] [Accepted: 05/17/2021] [Indexed: 11/12/2022] Open
Abstract
Ants show remarkable ecological and evolutionary success due to their social life history and division of labour among colony members. In some lineages, the worker force became subdivided into morphologically distinct individuals (i.e. minor versus major workers), allowing for the differential performance of particular roles in the colony. However, the functional and ecological significance of these morphological differences are not well understood. Here, we applied finite element analysis (FEA) to explore the biomechanical differences between major and minor ant worker mandibles. Analyses were carried out on mandibles of two Pheidole species, a dimorphic ant genus. We tested whether major mandibles evolved to minimize stress when compared to minors using combinations of the apical tooth and masticatory margin bites under strike and pressure conditions. Majors performed better in pressure conditions yet, contrary to our expectations, minors performed better in strike bite scenarios. Moreover, we demonstrated that even small morphological differences in ant mandibles might lead to substantial differences in biomechanical responses to bite loading. These results also underscore the potential of FEA to uncover biomechanical consequences of morphological differences within and between ant workers.
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Affiliation(s)
- Cristian L. Klunk
- Graduate Program in Ecology and Conservation, Federal University of Paraná, Curitiba-PR, Brazil
| | - Marco A. Argenta
- Department of Civil Construction, Federal University of Paraná, Curitiba-PR, Brazil
| | - Alexandre Casadei-Ferreira
- Biodiversity and Biocomplexity Unit, Okinawa Institute of Science and Technology Graduate University, Onna, Japan
| | - Evan P. Economo
- Biodiversity and Biocomplexity Unit, Okinawa Institute of Science and Technology Graduate University, Onna, Japan
| | - Marcio R. Pie
- Graduate Program in Ecology and Conservation, Federal University of Paraná, Curitiba-PR, Brazil
- Department of Zoology, Federal University of Paraná, Curitiba-PR, Brazil
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16
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Casadei‐Ferreira A, Friedman NR, Economo EP, Pie MR, Feitosa RM. Head and mandible shapes are highly integrated yet represent two distinct modules within and among worker subcastes of the ant genus Pheidole. Ecol Evol 2021; 11:6104-6118. [PMID: 34141206 PMCID: PMC8207162 DOI: 10.1002/ece3.7422] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2020] [Revised: 02/14/2021] [Accepted: 02/23/2021] [Indexed: 11/10/2022] Open
Abstract
Ants use their mandibles for a wide variety of tasks related to substrate manipulation, brood transport, food processing, and colony defense. Due to constraints involved in colony upkeep, ants evolved a remarkable diversity of mandibular forms, often related to specific roles such as specialized hunting and seed milling. Considering these varied functional demands, we focused on understanding how the mandible and head shape vary within and between Pheidole subcastes. Using x-ray microtomography and 3D geometric morphometrics, we tested whether these structures are integrated and modular, and how ecological predictors influenced these features. Our results showed that mandible and head shape of majors and minor workers tend to vary from robust to slender, with some more complex changes related to the mandibular base. Additionally, we found that head and mandible shapes are characterized by a high degree of integration, but with little correlation with feeding and nesting habits. Our results suggest that a combination of structural (allometric) constraints and the behavioral flexibility conferred by subcaste dimorphism might largely buffer selective pressures that would otherwise lead to a fine-tuning between ecological conditions and morphological adaptation.
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Affiliation(s)
- Alexandre Casadei‐Ferreira
- Departamento de ZoologiaUniversidade Federal do ParanáCuritibaBrazil
- Biodiversity and Biocomplexity UnitOkinawa Institute of Science and Technology Graduate UniversityOnnaJapan
| | - Nicholas R. Friedman
- Biodiversity and Biocomplexity UnitOkinawa Institute of Science and Technology Graduate UniversityOnnaJapan
| | - Evan P. Economo
- Biodiversity and Biocomplexity UnitOkinawa Institute of Science and Technology Graduate UniversityOnnaJapan
| | - Marcio R. Pie
- Departamento de ZoologiaUniversidade Federal do ParanáCuritibaBrazil
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17
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Taxonomic and morphological diversity of the ground-dwelling ant fauna in Eastern Amazonian grasslands. ACTA OECOLOGICA 2021. [DOI: 10.1016/j.actao.2020.103693] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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18
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Coto ZN, Traniello JFA. Brain Size, Metabolism, and Social Evolution. Front Physiol 2021; 12:612865. [PMID: 33708134 PMCID: PMC7940180 DOI: 10.3389/fphys.2021.612865] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Accepted: 02/01/2021] [Indexed: 12/24/2022] Open
Affiliation(s)
- Zach N Coto
- Department of Biology, Boston University, Boston, MA, United States
| | - James F A Traniello
- Department of Biology, Boston University, Boston, MA, United States.,Graduate Program in Neuroscience, Boston University, Boston, MA, United States
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19
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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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20
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Villagra C, Frías-Lasserre D. Epigenetic Molecular Mechanisms in Insects. NEOTROPICAL ENTOMOLOGY 2020; 49:615-642. [PMID: 32514997 DOI: 10.1007/s13744-020-00777-8] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/20/2019] [Accepted: 04/06/2020] [Indexed: 06/11/2023]
Abstract
Insects are the largest animal group on Earth both in biomass and diversity. Their outstanding success has inspired genetics and developmental research, allowing the discovery of dynamic process explaining extreme phenotypic plasticity and canalization. Epigenetic molecular mechanisms (EMMs) are vital for several housekeeping functions in multicellular organisms, regulating developmental, ontogenetic trajectories and environmental adaptations. In Insecta, EMMs are involved in the development of extreme phenotypic divergences such as polyphenisms and eusocial castes. Here, we review the history of this research field and how the main EMMs found in insects help to understand their biological processes and diversity. EMMs in insects confer them rapid response capacity allowing insect either to change with plastic divergence or to keep constant when facing different stressors or stimuli. EMMs function both at intra as well as transgenerational scales, playing important roles in insect ecology and evolution. We discuss on how EMMs pervasive influences in Insecta require not only the control of gene expression but also the dynamic interplay of EMMs with further regulatory levels, including genetic, physiological, behavioral, and environmental among others, as was earlier proposed by the Probabilistic Epigenesis model and Developmental System Theory.
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Affiliation(s)
- C Villagra
- Instituto de Entomología, Univ Metropolitana de Ciencias de la Educación, Santiago, Chile.
| | - D Frías-Lasserre
- Instituto de Entomología, Univ Metropolitana de Ciencias de la Educación, Santiago, Chile
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21
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Friedman NR, Lecroq Bennet B, Fischer G, Sarnat EM, Huang J, Knowles LLK, Economo EP. Macroevolutionary integration of phenotypes within and across ant worker castes. Ecol Evol 2020; 10:9371-9383. [PMID: 32953067 PMCID: PMC7487254 DOI: 10.1002/ece3.6623] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2020] [Revised: 06/27/2020] [Accepted: 06/29/2020] [Indexed: 11/11/2022] Open
Abstract
Phenotypic traits are often integrated into evolutionary modules: sets of organismal parts that evolve together. In social insect colonies, the concepts of integration and modularity apply to sets of traits both within and among functionally and phenotypically differentiated castes. On macroevolutionary timescales, patterns of integration and modularity within and across castes can be clues to the selective and ecological factors shaping their evolution and diversification. We develop a set of hypotheses describing contrasting patterns of worker integration and apply this framework in a broad (246 species) comparative analysis of major and minor worker evolution in the hyperdiverse ant genus Pheidole. Using geometric morphometrics in a phylogenetic framework, we inferred fast and tightly integrated evolution of mesosoma shape between major and minor workers, but slower and more independent evolution of head shape between the two worker castes. Thus, Pheidole workers are evolving as a mixture of intracaste and intercaste integration and rate heterogeneity. The decoupling of homologous traits across worker castes may represent an important process facilitating the rise of social complexity.
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Affiliation(s)
- Nicholas R. Friedman
- Biodiversity and Biocomplexity UnitOkinawa Institute of Science and Technology Graduate UniversityOkinawaJapan
| | - Beatrice Lecroq Bennet
- Biodiversity and Biocomplexity UnitOkinawa Institute of Science and Technology Graduate UniversityOkinawaJapan
| | - Georg Fischer
- Biodiversity and Biocomplexity UnitOkinawa Institute of Science and Technology Graduate UniversityOkinawaJapan
| | - Eli M. Sarnat
- Biodiversity and Biocomplexity UnitOkinawa Institute of Science and Technology Graduate UniversityOkinawaJapan
| | - Jen‐Pan Huang
- Department of Ecology and Evolutionary Biology, Museum of ZoologyUniversity of MichiganAnn ArborMIUSA
- Biodiversity Research CenterAcademia SinicaTaipeiTaiwan
| | - L. Lacey Knowles Knowles
- Department of Ecology and Evolutionary Biology, Museum of ZoologyUniversity of MichiganAnn ArborMIUSA
| | - Evan P. Economo
- Biodiversity and Biocomplexity UnitOkinawa Institute of Science and Technology Graduate UniversityOkinawaJapan
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22
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Ortiz-Alvarado Y, Rivera-Marchand B. Worker Queens? Behavioral Flexibility of Queens in the Little Fire Ant Wasmannia auropunctata. Front Ecol Evol 2020. [DOI: 10.3389/fevo.2020.00241] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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23
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Cini A, Bordoni A, Cappa F, Petrocelli I, Pitzalis M, Iovinella I, Dani FR, Turillazzi S, Cervo R. Increased immunocompetence and network centrality of allogroomer workers suggest a link between individual and social immunity in honeybees. Sci Rep 2020; 10:8928. [PMID: 32488140 PMCID: PMC7265547 DOI: 10.1038/s41598-020-65780-w] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2019] [Accepted: 04/24/2020] [Indexed: 01/11/2023] Open
Abstract
The significant risk of disease transmission has selected for effective immune-defense strategies in insect societies. Division of labour, with individuals specialized in immunity-related tasks, strongly contributes to prevent the spread of diseases. A trade-off, however, may exist between phenotypic specialization to increase task efficiency and maintenance of plasticity to cope with variable colony demands. We investigated the extent of phenotypic specialization associated with a specific task by using allogrooming in the honeybee, Apis mellifera, where worker behaviour might lower ectoparasites load. We adopted an integrated approach to characterize the behavioural and physiological phenotype of allogroomers, by analyzing their behavior (both at individual and social network level), their immunocompetence (bacterial clearance tests) and their chemosensory specialization (proteomics of olfactory organs). We found that allogroomers have higher immune capacity compared to control bees, while they do not differ in chemosensory proteomic profiles. Behaviourally, they do not show differences in the tasks performed (other than allogrooming), while they clearly differ in connectivity within the colonial social network, having a higher centrality than control bees. This demonstrates the presence of an immune-specific physiological and social behavioural specialization in individuals involved in a social immunity related task, thus linking individual to social immunity, and it shows how phenotypes may be specialized in the task performed while maintaining an overall plasticity.
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Affiliation(s)
- Alessandro Cini
- Dipartimento di Biologia, Università di Firenze, Via Madonna del Piano 6, 50019, Sesto Fiorentino, Firenze, Italy.
- Centre for Biodiversity and Environment Research, University College London, Gower Street, London, WC1E 6BT, UK.
| | - Adele Bordoni
- Dipartimento di Biologia, Università di Firenze, Via Madonna del Piano 6, 50019, Sesto Fiorentino, Firenze, Italy
| | - Federico Cappa
- Dipartimento di Biologia, Università di Firenze, Via Madonna del Piano 6, 50019, Sesto Fiorentino, Firenze, Italy
| | - Iacopo Petrocelli
- Dipartimento di Biologia, Università di Firenze, Via Madonna del Piano 6, 50019, Sesto Fiorentino, Firenze, Italy
| | - Martina Pitzalis
- Dipartimento di Biologia, Università di Firenze, Via Madonna del Piano 6, 50019, Sesto Fiorentino, Firenze, Italy
| | - Immacolata Iovinella
- Dipartimento di Biologia, Università di Firenze, Via Madonna del Piano 6, 50019, Sesto Fiorentino, Firenze, Italy
| | - Francesca Romana Dani
- Dipartimento di Biologia, Università di Firenze, Via Madonna del Piano 6, 50019, Sesto Fiorentino, Firenze, Italy
- CISM, Mass Spectrometry Centre, Università di Firenze, Via U. Schiff 6, 50019, Sesto Fiorentino, Firenze, Italy
| | - Stefano Turillazzi
- Dipartimento di Biologia, Università di Firenze, Via Madonna del Piano 6, 50019, Sesto Fiorentino, Firenze, Italy
| | - Rita Cervo
- Dipartimento di Biologia, Università di Firenze, Via Madonna del Piano 6, 50019, Sesto Fiorentino, Firenze, Italy
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24
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Task partitioning in ants lacking discrete morphological worker subcastes. Behav Ecol Sociobiol 2020. [DOI: 10.1007/s00265-020-02845-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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25
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Abstract
Nest choice in Temnothorax spp.; task allocation and the regulation of activity in Pheidole dentata, Pogonomyrmex barbatus, and Atta spp.; and trail networks in Monomorium pharaonis and Cephalotes goniodontus all provide examples of correspondences between the dynamics of the environment and the dynamics of collective behavior. Some important aspects of the dynamics of the environment include stability, the threat of rupture or disturbance, the ratio of inflow and outflow of resources or energy, and the distribution of resources. These correspond to the dynamics of collective behavior, including the extent of amplification, how feedback instigates and inhibits activity, and the extent to which the interactions that provide the information to regulate behavior are local or spatially centralized.
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Affiliation(s)
- Deborah M Gordon
- Department of Biology, Stanford University, Stanford, California 94305-5020, USA;
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26
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Finkelstein AB, Amdam GV. Aversive Foraging Conditions Modulate Downstream Social Food Sharing. Sci Rep 2018; 8:17764. [PMID: 30531822 PMCID: PMC6288118 DOI: 10.1038/s41598-018-35910-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2018] [Accepted: 11/09/2018] [Indexed: 11/09/2022] Open
Abstract
Eusocial insects divide their labour so that individuals working inside the nest are affected by external conditions through a cascade of social interactions. Honey bees (Apis mellifera) transfer food and information via mouth-to-mouth social feeding, ie trophallaxis, a process known to be modulated by the rate of food flow at feeders and familiarity of food's scent. Little is understood about how aversive foraging conditions such as predation and con-specific competition affect trophallaxis. We hypothesized that aversive conditions have an impact on food transfer inside the colony. Here we explore the effect of foragers' aversive experience on downstream trophallaxis in a cage paradigm. Each cage contained one group of bees that was separated from feeders by mesh and allowed to feed only through trophallaxis, and another group that had access to feeders and self-specialized to either forage or distribute food. Our results show that aversive foraging conditions increase non-foragers' trophallaxis with bees restricted from feeder access when food is scented, and have the opposite effect when food is unscented. We discuss potential behavioural mechanisms and implications for the impact of aversive conditions such as malaise inducing toxins, predation, and con-specific competition.
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Affiliation(s)
- Abby Basya Finkelstein
- School of Life Sciences, Arizona State University, Tempe, USA. .,Psychological and Brain Sciences, Boston University, Massachusetts, USA.
| | - Gro V Amdam
- School of Life Sciences, Arizona State University, Tempe, USA.,Faculty of Environmental Sciences and Natural Resource Management, Norwegian University of Life Sciences, Aas, Norway
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27
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Synaptic organization and division of labor in the exceptionally polymorphic ant Pheidole rhea. Neurosci Lett 2018; 676:46-50. [PMID: 29625207 DOI: 10.1016/j.neulet.2018.04.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2018] [Revised: 03/18/2018] [Accepted: 04/01/2018] [Indexed: 11/22/2022]
Abstract
Social insect polyphenisms provide models to examine the neural basis of division of labor and anatomy of the invertebrate social brain. Worker size-related behavior is hypothesized to enhance task performance, raising questions concerning the integration of morphology, behavior, and cellular neuroarchitecture, and how variation in sensory inputs and cognitive demands of behaviorally differentiated workers is reflected in higher-order processing ability. We used the highly polymorphic ant Pheidole rhea, which has three distinct worker size classes - minors, soldiers, and supersoldiers - to examine variation in synaptic circuitry across worker size and social role. We hypothesized that the density and size of synaptic complexes (microglomeruli, MG) would be positively associated with behavioral repertoire and the relative size of the mushroom bodies (MB). Supersoldiers had significantly larger and less dense MG in the lip (olfactory region) of the MB calyx (MBC), and larger MG in the collar (visual region) compared to minors. Soldiers were intermediate in synaptic phenotype: they did not differ significantly in MG density from minors and supersoldiers, had MG of similar size to minors in the lip, and did not differ from these two worker groups in MG size in the collar. Results suggest a complex relationship between MG density, size, behavior, and worker body size involving a conserved and plastic neurobiological development plan, although workers show strong variation in size and social role.
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28
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Wills BD, Powell S, Rivera MD, Suarez AV. Correlates and Consequences of Worker Polymorphism in Ants. ANNUAL REVIEW OF ENTOMOLOGY 2018; 63:575-598. [PMID: 29068707 DOI: 10.1146/annurev-ento-020117-043357] [Citation(s) in RCA: 52] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Body size is a key life-history trait influencing all aspects of an organism's biology. Ants provide an interesting model for examining body-size variation because of the high degree of worker polymorphism seen in many taxa. We review worker-size variation in ants from the perspective of factors internal and external to the colony that may influence body-size distributions. We also discuss proximate and ultimate causes of size variation and how variation in worker size can promote worker efficiency and colony fitness. Our review focuses on two questions: What is our current understanding of factors influencing worker-size variation? And how does variation in body size benefit the colony? We conclude with recommendations for future work aimed at addressing current limitations and ask, How can we better understand the contribution of worker body-size variation to colony success? And, what research is needed to address gaps in our knowledge?
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Affiliation(s)
- Bill D Wills
- Department of Entomology, Michigan State University, East Lansing, Michigan 48824, USA;
| | - Scott Powell
- Department of Biological Sciences, George Washington University, Washington, DC 20052, USA;
| | - Michael D Rivera
- Program in Ecology, Evolution and Conservation Biology, University of Illinois, Urbana, Illinois 61801, USA;
| | - Andrew V Suarez
- Program in Ecology, Evolution and Conservation Biology, University of Illinois, Urbana, Illinois 61801, USA;
- Department of Entomology, University of Illinois, Urbana, Illinois 61801, USA;
- Department of Animal Biology, University of Illinois, Urbana, Illinois 61801, USA
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29
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Kamhi JF, Gronenberg W, Robson SKA, Traniello JFA. Social complexity influences brain investment and neural operation costs in ants. Proc Biol Sci 2017; 283:rspb.2016.1949. [PMID: 27798312 DOI: 10.1098/rspb.2016.1949] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2016] [Accepted: 09/26/2016] [Indexed: 11/12/2022] Open
Abstract
The metabolic expense of producing and operating neural tissue required for adaptive behaviour is considered a significant selective force in brain evolution. In primates, brain size correlates positively with group size, presumably owing to the greater cognitive demands of complex social relationships in large societies. Social complexity in eusocial insects is also associated with large groups, as well as collective intelligence and division of labour among sterile workers. However, superorganism phenotypes may lower cognitive demands on behaviourally specialized workers resulting in selection for decreased brain size and/or energetic costs of brain metabolism. To test this hypothesis, we compared brain investment patterns and cytochrome oxidase (COX) activity, a proxy for ATP usage, in two ant species contrasting in social organization. Socially complex Oecophylla smaragdina workers had larger brain size and relative investment in the mushroom bodies (MBs)-higher order sensory processing compartments-than the more socially basic Formica subsericea workers. Oecophylla smaragdina workers, however, had reduced COX activity in the MBs. Our results suggest that as in primates, ant group size is associated with large brain size. The elevated costs of investment in metabolically expensive brain tissue in the socially complex O. smaragdina, however, appear to be offset by decreased energetic costs.
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Affiliation(s)
- J Frances Kamhi
- Department of Biology, Boston University, Boston, MA 02215, USA .,Graduate Program for Neuroscience, Boston University, Boston, MA 02215, USA
| | - Wulfila Gronenberg
- Department of Neuroscience, University of Arizona, Tucson, AZ 85721, USA
| | - Simon K A Robson
- Zoology and Ecology, James Cook University, Townsville, Queensland 4811, Australia
| | - James F A Traniello
- Department of Biology, Boston University, Boston, MA 02215, USA.,Graduate Program for Neuroscience, Boston University, Boston, MA 02215, USA
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Behavior, brain, and morphology in a complex insect society: trait integration and social evolution in the exceptionally polymorphic ant Pheidole rhea. Behav Ecol Sociobiol 2017. [DOI: 10.1007/s00265-017-2396-z] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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Gordon DG, Zelaya A, Ronk K, Traniello JFA. Interspecific comparison of mushroom body synaptic complexes of dimorphic workers in the ant genus Pheidole. Neurosci Lett 2017; 662:110-114. [PMID: 29024727 DOI: 10.1016/j.neulet.2017.10.009] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2017] [Revised: 09/03/2017] [Accepted: 10/08/2017] [Indexed: 10/18/2022]
Abstract
Social insects may have morphologically and behaviorally specialized workers that vary in requirements for sensory information processing, making them excellent systems to examine the relationship between brain structure and behavior. The density and size of synaptic complexes (microglomeruli, MG) in the mushroom bodies (MB) have served as proxies for processing ability and synaptic plasticity, and have been shown to vary among insect species that differ in behavioral complexity. To understand the relationship between behavioral specialization and synaptic structure, we examined age-related changes in MG density and size between minor worker and soldier subcastes in two species of Pheidole ants, P. dentata and P. morrisi, that differ in behavior. We hypothesized that task-diverse minor workers would have more densely packed MG than soldiers, and that species-specific differences in soldier repertories would be reflected in MG structure. We also examined MG variation in young and mature minor workers and soldiers, predicting that as workers age and develop behaviorally, MG would decrease in density in both subcastes due to synaptic pruning. Results support the hypothesis that MG density in the lip (olfactory) and collar (visual) regions of the MBs decrease with age in association with increases in bouton size in the lip. However, minors had significantly lower densities of MG in the lip than soldiers, suggesting MG may not show structural variation according to subcaste-related differences in cognitive demands in either species.
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Affiliation(s)
- Darcy G Gordon
- Department of Biology, Boston University, 5 Cummington Mall, Boston MA, 02215, USA.
| | - Alejandra Zelaya
- Department of Biology, Boston University, 5 Cummington Mall, Boston MA, 02215, USA
| | - Katherine Ronk
- Department of Biology, Boston University, 5 Cummington Mall, Boston MA, 02215, USA
| | - James F A Traniello
- Department of Biology, Boston University, 5 Cummington Mall, Boston MA, 02215, USA; Graduate Program for Neuroscience, Boston University, 5 Cummington Mall, Boston, MA, 02215, USA
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Sarnat EM, Friedman NR, Fischer G, Lecroq-Bennet B, Economo EP. Rise of the spiny ants: diversification, ecology and function of extreme traits in the hyperdiverse genus Pheidole (Hymenoptera: Formicidae). Biol J Linn Soc Lond 2017. [DOI: 10.1093/biolinnean/blx081] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
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Lillico-Ouachour A, Abouheif E. Regulation, development, and evolution of caste ratios in the hyperdiverse ant genus Pheidole. CURRENT OPINION IN INSECT SCIENCE 2017; 19:43-51. [PMID: 28521942 DOI: 10.1016/j.cois.2016.11.003] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/07/2016] [Revised: 11/23/2016] [Accepted: 11/24/2016] [Indexed: 06/07/2023]
Abstract
Ant colonies are considered complex biological systems because many individuals are divided into different castes that interact to efficiently perform their tasks. Colonies in the hyperdiverse ant genus Pheidole have evolved a worker caste with at least two subcastes: soldiers and minor workers. The proportion of soldiers and minor workers in a colony has a major impact on the colony's fitness and is tightly regulated. Here, we summarize over 100 years of research on the internal, external, and developmental factors that regulate subcaste production as well as influence subcaste evolution in Pheidole. We hope that summarizing these factors into a network of interactions will provide insight into how complex biological systems regulate, develop, and evolve.
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Affiliation(s)
- Angelica Lillico-Ouachour
- Department of Biology, McGill University, 1205 Avenue Docteur Penfield, Montréal, QC, Canada H3A 1B1
| | - Ehab Abouheif
- Department of Biology, McGill University, 1205 Avenue Docteur Penfield, Montréal, QC, Canada H3A 1B1.
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Segers FHID, von Zuben L, Grüter C. Local differences in parasitism and competition shape defensive investment in a polymorphic eusocial bee. Ecology 2016; 97:417-26. [PMID: 27145616 DOI: 10.1890/15-0793.1] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Many colonial animals rely for their defense on a soldier caste. Adaptive colony demography theory predicts that colonies should flexibly adjust the investment in different worker castes depending on the colony needs. For example, colonies should invest more in defensive workers (e.g., soldiers) in dangerous environments. However, evidence for this prediction has been mixed. We combined descriptive and experimental approaches to examine whether defensive investment and worker size are adjusted to local ecology in the only known bee with polymorphic workers, Tetragonisca angustula. Colonies of this species are defended by a morphologically specialized soldier caste. Our study included three populations that differed in the density of food competition and the occurrence of a parasitic robber bee. We found that colonies coexisting with robber bees had on average 43% more soldiers defending the nest entrance, while colonies facing stronger foraging competition had soldiers that were -6-7% smaller. We then experimentally relocated colonies to areas with different levels of competition. When released from intense food competition, body sizes of guards and foragers increased. After introducing chemical robber bee cues at nest entrances, we found both a short-term and a long-term up-regulation of the number of soldiers defending the colony. Active soldier numbers remained high after the experiment for a duration equivalent to 2-3 worker life spans. How information about past parasite threat is stored in the colony is currently unknown. In summary, T. angustula adjusts both the number and the body size of active soldiers to local ecological conditions. Competitor density also affects forager (or minor) size, an important colony trait with potential community ecological consequences. Our study supports adaptive colony demography theory in a eusocial bee and highlights the importance of colony threats and competition as selective forces shaping colony phenotype.
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Kamhi JF, Nunn K, Robson SKA, Traniello JFA. Polymorphism and division of labour in a socially complex ant: neuromodulation of aggression in the Australian weaver ant, Oecophylla smaragdina. Proc Biol Sci 2016; 282:rspb.2015.0704. [PMID: 26136448 DOI: 10.1098/rspb.2015.0704] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Complex social structure in eusocial insects can involve worker morphological and behavioural differentiation. Neuroanatomical variation may underscore worker division of labour, but the regulatory mechanisms of size-based task specialization in polymorphic species are unknown. The Australian weaver ant, Oecophylla smaragdina, exhibits worker polyphenism: larger major workers aggressively defend arboreal territories, whereas smaller minors nurse brood.Here, we demonstrate that octopamine (OA) modulates worker size-related aggression in O. smaragdina. We found that the brains of majors had significantly higher titres of OA than those of minors and that OA was positively and specifically correlated with the frequency of aggressive responses to non-nestmates, a key component of territorial defence. Pharmacological manipulations that effectively switched OA action in major and minor worker brains reversed levels of aggression characteristic of each worker size class. Results suggest that altering OA action is sufficient to produce differences in aggression characteristic of size-related social roles. Neuromodulators therefore may generate variation in responsiveness to task-related stimuli associated with worker size differentiation and collateral behavioural specializations, a significant component of division of labour in complex social systems.
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Holley JAC, Moreau CS, Laird JG, Suarez AV. Subcaste-specific evolution of head size in the ant genusPheidole. Biol J Linn Soc Lond 2016. [DOI: 10.1111/bij.12769] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Affiliation(s)
- Jo-Anne C. Holley
- Department of Entomology; University of Illinois; 320 Morrill Hall 505 S. Goodwin Ave Urbana IL 61801 USA
| | - Corrie S. Moreau
- Department of Science and Education; Center for Integrative Research; Field Museum of Natural History; 1400 South Lake Shore Drive Chicago IL 60605 USA
| | - Joseph G. Laird
- Department of Biochemistry; University of Iowa; 4-403 BSB Iowa City IA 52242 USA
| | - Andrew V. Suarez
- Department of Entomology; University of Illinois; 320 Morrill Hall 505 S. Goodwin Ave Urbana IL 61801 USA
- Department of Animal Biology; University of Illinois; 515 Morrill Hall 505 S. Goodwin Ave Urbana IL 61801 USA
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Powell S. A comparative perspective on the ecology of morphological diversification in complex societies: nesting ecology and soldier evolution in the turtle ants. Behav Ecol Sociobiol 2016. [DOI: 10.1007/s00265-016-2080-8] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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Ilieş I, Muscedere ML, Traniello JF. Neuroanatomical and Morphological Trait Clusters in the Ant Genus Pheidole: Evidence for Modularity and Integration in Brain Structure. BRAIN, BEHAVIOR AND EVOLUTION 2015; 85:63-76. [DOI: 10.1159/000370100] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/29/2014] [Accepted: 08/28/2014] [Indexed: 11/19/2022]
Abstract
A central question in brain evolution concerns how selection has structured neuromorphological variation to generate adaptive behavior. In social insects, brain structures differ between reproductive and sterile castes, and worker behavioral specializations related to morphology, age, and ecology are associated with intra- and interspecific variation in investment in functionally different brain compartments. Workers in the hyperdiverse ant genus Pheidole are morphologically and behaviorally differentiated into minor and major subcastes that exhibit distinct species-typical patterns of brain compartment size variation. We examined integration and modularity in brain organization and its developmental patterning in three ecotypical Pheidole species by analyzing intra- and interspecific morphological and neuroanatomical covariation. Our results identified two trait clusters, the first involving olfaction and social information processing and the second composed of brain regions regulating nonolfactory sensorimotor functions. Patterns of size covariation between brain compartments within subcastes were consistent with levels of behavioral differentiation between minor and major workers. Globally, brains of mature workers were more heterogeneous than brains of newly eclosed workers, suggesting diversified developmental trajectories underscore species- and subcaste-typical brain organization. Variation in brain structure associated with the striking worker polyphenism in our sample of Pheidole appears to originate from initially differentiated brain templates that further diverge through species- and subcaste-specific processes of maturation and behavioral development.
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Wills BD, Moreau CS, Wray BD, Hoffmann BD, Suarez AV. Body size variation and caste ratios in geographically distinct populations of the invasive big-headed ant,Pheidole megacephala(Hymenoptera: Formicidae). Biol J Linn Soc Lond 2014. [DOI: 10.1111/bij.12386] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Bill D. Wills
- Department of Animal Biology; University of Illinois; 515 Morrill Hall, 505 S. Goodwin Ave. Urbana IL 61801 USA
| | - Corrie S. Moreau
- Department of Science and Education; Center for Integrative Research; Field Museum of Natural History; 1400 South Lake Shore Drive Chicago IL 60605 USA
| | - Brian D. Wray
- Department of Science and Education; Center for Integrative Research; Field Museum of Natural History; 1400 South Lake Shore Drive Chicago IL 60605 USA
| | - Benjamin D. Hoffmann
- CSIRO Land and Water Flagship, Tropical Ecosystems Research Centre; PMB 44 Winnellie NT 0822 Australia
| | - Andrew V. Suarez
- Department of Animal Biology; University of Illinois; 515 Morrill Hall, 505 S. Goodwin Ave. Urbana IL 61801 USA
- Program in Ecology, Evolution and Conservation Biology; Department of Entomology; University of Illinois; 320 Morrill Hall, 505 S. Goodwin Ave. Urbana IL 61801 USA
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41
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Arnan X, Cerdá X, Retana J. Ant functional responses along environmental gradients. J Anim Ecol 2014; 83:1398-408. [DOI: 10.1111/1365-2656.12227] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2013] [Accepted: 03/24/2014] [Indexed: 11/26/2022]
Affiliation(s)
- Xavier Arnan
- CREAF; Cerdanyola del Vallès 08193 Catalunya Spain
- Faculty of Biology; TU Darmstadt; Schnittspahnstrasse 3 D-64287 Darmstadt Germany
| | - Xim Cerdá
- Estación Biológica de Doñana; CSIC; Avda Américo Vespucio, s/n E-41092 Sevilla Spain
| | - Javier Retana
- CREAF; Cerdanyola del Vallès 08193 Catalunya Spain
- Univ Autònoma Barcelona; Cerdanyola del Vallès 08193 Catalunya Spain
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42
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Scholes DR, Suarez AV, Paige KN. Can endopolyploidy explain body size variation within and between castes in ants? Ecol Evol 2013; 3:2128-37. [PMID: 23919157 PMCID: PMC3728952 DOI: 10.1002/ece3.623] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2013] [Revised: 04/30/2013] [Accepted: 05/06/2013] [Indexed: 11/13/2022] Open
Abstract
Endoreduplication is the process by which the nuclear genome is repeatedly replicated without mitotic cell division, resulting in nuclei that contain numerous additional genome copies. Endoreduplication occurs widely throughout Eucarya and is particularly common in angiosperms and insects. Although endoreduplication is an important process in the terminal differentiation of some specialized cell types, and often increases cell size and metabolism, the direct effects of increasing nuclear ploidy on cell function are not well resolved. Here, we examine if endoreduplication may play a role in body size and/or caste differentiation in ants. Nuclear ploidy was measured by flow cytometry of whole individuals (providing the basis for overall body size patterns) and individual body segments for multiple polymorphic ant species. We used cell cycle values, interpreted as the mean number of endocycles performed by each cell in the sample, as our measure of overall endoreduplication. Among females of four polymorphic ant species, endoreduplication was positively related with size within the worker caste, but was not related to caste generally in two species where we also examined queens. Additionally, abdomens had the greatest endoreduplication of all body parts regardless of caste or size. We also found that males, having derived from haploid unfertilized eggs, had the highest rates of endoreduplication and may compensate for their haploid origin by performing an additional endocycle relative to females. These results suggest that endoreduplication may play a role in body size variation in eusocial insects and the development of some segment-specific tissues.
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Affiliation(s)
- Daniel R Scholes
- Program in Ecology Evolution and Conservation Biology, University of Illinois at Urbana-Champaign 515 Morrill Hall, 505 S Goodwin Ave, Urbana, Illinois, 61801
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Kamhi JF, Traniello JF. Biogenic Amines and Collective Organization in a Superorganism: Neuromodulation of Social Behavior in Ants. BRAIN, BEHAVIOR AND EVOLUTION 2013; 82:220-36. [DOI: 10.1159/000356091] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/28/2013] [Accepted: 09/26/2013] [Indexed: 11/19/2022]
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McGlynn TP, Diamond SE, Dunn RR. Tradeoffs in the evolution of caste and body size in the hyperdiverse ant genus Pheidole. PLoS One 2012; 7:e48202. [PMID: 23133570 PMCID: PMC3485035 DOI: 10.1371/journal.pone.0048202] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2012] [Accepted: 09/24/2012] [Indexed: 11/24/2022] Open
Abstract
The efficient investment of resources is often the route to ecological success, and the adaptability of resource investment may play a critical role in promoting biodiversity. The ants of the “hyperdiverse” genus Pheidole produce two discrete sterile castes, soldiers and minor workers. Within Pheidole, there is tremendous interspecific variation in proportion of soldiers. The causes and correlates of caste ratio variation among species of Pheidole remain enigmatic. Here we test whether a body size threshold model accounts for interspecific variation in caste ratio in Pheidole, such that species with larger body sizes produce relatively fewer soldiers within their colonies. We evaluated the caste ratio of 26 species of Pheidole and found that the body size of workers accounts for interspecific variation in the production of soldiers as we predicted. Twelve species sampled from one forest in Costa Rica yielded the same relationship as found in previously published data from many localities. We conclude that production of soldiers in the most species-rich group of ants is regulated by a body size threshold mechanism, and that the great variation in body size and caste ratio in Pheidole plays a role in niche divergence in this rapidly evolving taxon.
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Affiliation(s)
- Terrence P McGlynn
- Department of Biology, California State University Dominguez Hills, Carson, California, United States of America.
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Muscedere ML, Traniello JFA. Division of labor in the hyperdiverse ant genus Pheidole is associated with distinct subcaste- and age-related patterns of worker brain organization. PLoS One 2012; 7:e31618. [PMID: 22363686 PMCID: PMC3281964 DOI: 10.1371/journal.pone.0031618] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2011] [Accepted: 01/10/2012] [Indexed: 11/21/2022] Open
Abstract
The evolutionary success of ants and other social insects is considered to be intrinsically linked to division of labor among workers. The role of the brains of individual ants in generating division of labor, however, is poorly understood, as is the degree to which interspecific variation in worker social phenotypes is underscored by functional neurobiological differentiation. Here we demonstrate that dimorphic minor and major workers of different ages from three ecotypical species of the hyperdiverse ant genus Pheidole have distinct patterns of neuropil size variation. Brain subregions involved in sensory input (optic and antennal lobes), sensory integration, learning and memory (mushroom bodies), and motor functions (central body and subesophageal ganglion) vary significantly in relative size, reflecting differential investment in neuropils that likely regulate subcaste- and age-correlated task performance. Worker groups differ in brain size and display patterns of altered isometric and allometric subregion scaling that affect brain architecture independently of brain size variation. In particular, mushroom body size was positively correlated with task plasticity in the context of both age- and subcaste-related polyethism, providing strong, novel support that greater investment in this neuropil increases behavioral flexibility. Our findings reveal striking levels of developmental plasticity and evolutionary flexibility in Pheidole worker neuroanatomy, supporting the hypothesis that mosaic alterations of brain composition contribute to adaptive colony structure and interspecific variation in social organization.
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Affiliation(s)
- Mario L Muscedere
- Department of Biology, Boston University, Boston, Massachusetts, United States of America.
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Duarte A, Weissing FJ, Pen I, Keller L. An Evolutionary Perspective on Self-Organized Division of Labor in Social Insects. ANNUAL REVIEW OF ECOLOGY EVOLUTION AND SYSTEMATICS 2011. [DOI: 10.1146/annurev-ecolsys-102710-145017] [Citation(s) in RCA: 122] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Ana Duarte
- Department of Theoretical Biology, Center for Ecological and Evolutionary Studies, University of Groningen, Groningen, 9747 AG The Netherlands; , ,
| | - Franz J. Weissing
- Department of Theoretical Biology, Center for Ecological and Evolutionary Studies, University of Groningen, Groningen, 9747 AG The Netherlands; , ,
| | - Ido Pen
- Department of Theoretical Biology, Center for Ecological and Evolutionary Studies, University of Groningen, Groningen, 9747 AG The Netherlands; , ,
| | - Laurent Keller
- Department of Ecology and Evolution, University of Lausanne, Lausanne, CH-1015 Switzerland;
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47
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Johnson BR. Task partitioning in honey bees: the roles of signals and cues in group-level coordination of action. Behav Ecol 2010. [DOI: 10.1093/beheco/arq138] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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