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McNeil DJ, Rodewald AD, Ruiz‐Gutierrez V, Fiss CJ, Larkin JL. Heterogeneity in breeding productivity is driven largely by factors affecting nestlings and young fledglings in an imperiled migratory passerine. Ecol Evol 2024; 14:e11327. [PMID: 38774142 PMCID: PMC11106047 DOI: 10.1002/ece3.11327] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2024] [Revised: 04/03/2024] [Accepted: 04/09/2024] [Indexed: 05/24/2024] Open
Abstract
Identifying factors that drive variation in vital rates among populations is a prerequisite to understanding a species' population biology and, ultimately, to developing effective conservation strategies. This is especially true for imperiled species like the golden-winged warbler (Vermivora chrysoptera) that exhibit strong spatial heterogeneity in demography and responds variably to conservation interventions. Habitat management actions recommended for breeding grounds conservation include timber harvest, shrub shearing, and prescribed fire that maintain or create early successional woody communities. Herein, we assessed variation in the survival of nests [n = 145] and fledglings [n = 134] at 17 regenerating timber harvest sites within two isolated populations in Pennsylvania that differed in productivity and response to habitat management. Although the overall survival of nests and fledglings was higher in the eastern population than the central population, this was only true when the nest phases and fledgling phases were considered wholly. Indeed, survival rates of nestlings and recently fledged young (1-5 days post-fledging) were lower in the central population, whereas eggs and older fledglings (6-30 days post-fledging) survived at comparable rates in both populations. Fledglings in the central population were smaller (10% lower weight) and begged twice as much as those in the eastern population, suggesting food limitation may contribute to lower survival rates. Fledgling survival in the central population, but not the eastern, also was a function of habitat features (understory vegetation density [positive] and distance to mature forest [negative]) and individual factors (begging effort [negative]). Our findings illustrate how identifying how survival varies across specific life stages can elucidate potential underlying demographic drivers, such as food resources in this case. In this way, our work underscores the importance of studying and decomposing stage-specific demography in species of conservation concern.
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Affiliation(s)
- Darin J. McNeil
- Department of Forestry and Natural ResourcesUniversity of KentuckyLexingtonKentuckyUSA
| | - Amanda D. Rodewald
- Cornell Laboratory of OrnithologyIthacaNew YorkUSA
- Department of Natural Resources and the EnvironmentCornell UniversityIthacaNew YorkUSA
| | | | - Cameron J. Fiss
- Department of Biological SciencesUniversity of PittsburghPittsburghPennsylvaniaUSA
| | - Jeffery L. Larkin
- Department of BiologyIndiana University of PennsylvaniaIndianaPennsylvaniaUSA
- American Bird ConservancyThe PlainsVirginiaUSA
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Xavier GM, Moura RR, Vasconcellos-Neto J, Gonzaga MO. Influences of sociality and maternal size on reproductive strategies: trade-offs between offspring size and quantity in five Anelosimus species (Araneae, Theridiidae). THE SCIENCE OF NATURE - NATURWISSENSCHAFTEN 2024; 111:7. [PMID: 38315245 DOI: 10.1007/s00114-024-01895-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/07/2023] [Revised: 01/27/2024] [Accepted: 01/30/2024] [Indexed: 02/07/2024]
Abstract
Individuals can experience accentuated disputes for resources when living with many conspecifics, even in situations in which cooperative behaviors assure benefits associated with an increase in the frequency of food acquisition and in diet breadth. Thus, intraspecific competition may exert a significant selective pressure on social animals. Theoretical models suggest that females of social species could improve their fitness by producing relatively large offspring, since body size can provide competitive advantages during foraging activities. As female reserves are limited, the production of large offspring would occur at the expense of their number. Using five Anelosimus (Araneae, Theridiidae) species, we assessed whether the social ones produce fewer and larger eggs than the subsocials. In addition, we tested the effect of female size on the adoption of each particular reproductive strategy. Small females could hypothetically invest in producing large offspring since they cannot produce as many offspring as large females. Our results suggested that, indeed, sociality influences reproductive strategies. Females of social species produced fewer and larger offspring than females of subsocial species. Subsociality, in turn, would benefit the production of many small spiderlings, possibly because a large number of siblings is important to maintain and expand new webs and to subdue prey during their initial instars. Our results also indicated that large females produce more eggs without necessarily reduce their sizes. We discussed how the costs and benefits of group living may influence reproductive strategies.
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Affiliation(s)
- Gabriel M Xavier
- Programa de Pós-Graduação Em Ecologia, Conservação E Biodiversidade, Instituto de Biologia, Universidade Federal de Uberlândia, Uberlândia, MG, Brazil.
- Núcleo de Extensão E Pesquisa Em Ecologia E Evolução (NEPEE), Departamento de Ciências Agrárias E Naturais, Universidade Do Estado de Minas Gerais, UEMG, R. Ver. Geraldo Moisés da Silva, S/N - Universitário, Ituiutaba, MG, CEP 38302-192, Brazil.
| | - Rafael R Moura
- Núcleo de Extensão E Pesquisa Em Ecologia E Evolução (NEPEE), Departamento de Ciências Agrárias E Naturais, Universidade Do Estado de Minas Gerais, UEMG, R. Ver. Geraldo Moisés da Silva, S/N - Universitário, Ituiutaba, MG, CEP 38302-192, Brazil
| | - João Vasconcellos-Neto
- Departamento de Biologia Animal, Universidade Estadual de Campinas, Campinas, SP, Brazil
| | - Marcelo O Gonzaga
- Instituto de Biologia, Universidade Federal de Uberlândia, Uberlândia, MG, Brazil
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3
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Weerawansha N, Wang Q, He XZ. Reproductive plasticity in response to the changing cluster size during the breeding period: a case study in a spider mite. EXPERIMENTAL & APPLIED ACAROLOGY 2023; 91:237-250. [PMID: 37651032 PMCID: PMC10562284 DOI: 10.1007/s10493-023-00834-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/17/2023] [Accepted: 08/12/2023] [Indexed: 09/01/2023]
Abstract
Animals living in clusters should adjust their reproductive strategies to adapt to the social environment. Theories predict that the benefits of cluster living would outweigh the costs of competition. Yet, it is largely unknown how animals optimize their reproductive fitness in response to the changing social environment during their breeding period. We used Tetranychus ludeni Zacher, a haplodiploid spider mite, to investigate how the ovipositing females modified their life-history traits in response to the change of cluster size (i.e., aggregation and dispersal) with a consistent population density (1 ♀/cm2). We demonstrate that (1) after females were shifted from a large cluster (16 ♀♀) to small ones (1 ♀, 5 and 10 ♀♀), they laid fewer and larger eggs with a higher female-biased sex ratio; (2) after females were shifted from small clusters to a large one, they laid fewer and smaller eggs, also with a higher female-biased sex ratio, and (3) increasing egg size significantly increased offspring sex ratio (% daughters), but did not increase immature survival. The results suggest that (1) females fertilize more larger eggs laid in a small population but lower the fertilization threshold and fertilize smaller eggs in a larger population, and (2) the reproductive adjustments in terms of egg number and size may contribute more to minimize the mate competition among sons but not to increase the number of inhabitants in the next generation. The current study provides evidence that spider mites can manipulate their reproductive output and adjust offspring sex ratio in response to dynamic social environments.
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Affiliation(s)
- Nuwan Weerawansha
- School of Agriculture and Environment, Massey University, Private Bag 11222, Palmerston North, New Zealand
- Faculty of Animal Science and Export Agriculture, Uva Wellassa University of Sri Lanka, Passara Road, Badulla, 90000, Sri Lanka
| | - Qiao Wang
- School of Agriculture and Environment, Massey University, Private Bag 11222, Palmerston North, New Zealand
| | - Xiong Zhao He
- School of Agriculture and Environment, Massey University, Private Bag 11222, Palmerston North, New Zealand.
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4
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Kao AB, Hund AK, Santos FP, Young JG, Bhat D, Garland J, Oomen RA, McCreery HF. Opposing Responses to Scarcity Emerge from Functionally Unique Sociality Drivers. Am Nat 2023; 202:302-321. [PMID: 37606948 DOI: 10.1086/725426] [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] [Indexed: 08/23/2023]
Abstract
AbstractFrom biofilms to whale pods, organisms across taxa live in groups, thereby accruing numerous diverse benefits of sociality. All social organisms, however, pay the inherent cost of increased resource competition. One expects that when resources become scarce, this cost will increase, causing group sizes to decrease. Indeed, this occurs in some species, but there are also species for which group sizes remain stable or even increase under scarcity. What accounts for these opposing responses? We present a conceptual framework, literature review, and theoretical model demonstrating that differing responses to sudden resource shifts can be explained by which sociality benefit exerts the strongest selection pressure on a particular species. We categorize resource-related benefits of sociality into six functionally distinct classes and model their effect on the survival of individuals foraging in groups under different resource conditions. We find that whether, and to what degree, the optimal group size (or correlates thereof) increases, decreases, or remains constant when resource abundance declines depends strongly on the dominant sociality mechanism. Existing data, although limited, support our model predictions. Overall, we show that across a wide diversity of taxa, differences in how group size shifts in response to resource declines can be driven by differences in the primary benefits of sociality.
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Martin JS, Jaeggi AV, Koski SE. The social evolution of individual differences: Future directions for a comparative science of personality in social behavior. Neurosci Biobehav Rev 2023; 144:104980. [PMID: 36463970 DOI: 10.1016/j.neubiorev.2022.104980] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2022] [Revised: 11/21/2022] [Accepted: 11/29/2022] [Indexed: 12/05/2022]
Abstract
Personality is essential for understanding the evolution of cooperation and conflict in behavior. However, personality science remains disconnected from the field of social evolution, limiting our ability to explain how personality and plasticity shape phenotypic adaptation in social behavior. Researchers also lack an integrative framework for comparing personality in the contextualized and multifaceted behaviors central to social interactions among humans and other animals. Here we address these challenges by developing a social evolutionary approach to personality, synthesizing theory, methods, and organizing questions in the study of individuality and sociality in behavior. We critically review current measurement practices and introduce social reaction norm models for comparative research on the evolution of personality in social environments. These models demonstrate that social plasticity affects the heritable variance of personality, and that individual differences in social plasticity can further modify the rate and direction of adaptive social evolution. Future empirical studies of frequency- and density-dependent social selection on personality are crucial for further developing this framework and testing adaptive theory of social niche specialization.
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Affiliation(s)
- Jordan S Martin
- Human Ecology Group, Institute of Evolutionary Medicine, University of Zurich, Switzerland.
| | - Adrian V Jaeggi
- Human Ecology Group, Institute of Evolutionary Medicine, University of Zurich, Switzerland.
| | - Sonja E Koski
- Organismal and Evolutionary Biology, University of Helsinki, Finland.
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6
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Bechsgaard J, Jorgensen TH, Jønsson AK, Schou M, Bilde T. Impaired immune function accompanies social evolution in spiders. Biol Lett 2022; 18:20220331. [PMID: 36541093 PMCID: PMC9768628 DOI: 10.1098/rsbl.2022.0331] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
An efficient immune system is essential to the survival of many animals. Sociality increases risk of pathogen transmission, which should select for enhanced immune function. However, two hypotheses instead predict a weakened immune function: relaxed selection caused by social immunity/protection, and reduced efficacy of selection due to inbreeding, reproductive skew and female bias in social species that reduce effective population size and accelerate genetic drift. We assessed the effect of social evolution on immune function in a comparative study of two social spider species and their closely related subsocial sister species (genus Stegodyphus). The haemolymph of social species was less efficient in inhibiting bacterial growth of the potentially pathogenic bacteria Bacillus subtilis than that of subsocial species. Reduced efficacy of selection in social species was supported by comparative genomic analysis showing substantially elevated non-synonymous substitutions in immune genes in one of the social species. We propose that impaired immune function results from reduced efficacy of selection because the evolution of sociality in spiders is accompanied by demographic processes that elevate genetic drift. Positive feedback between pathogen-induced local extinctions and the resulting elevation of genetic drift may further weaken responses to selection by pathogens, and threaten species persistence.
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Affiliation(s)
| | | | | | - Mads Schou
- Department of Biology, Lund University, Lund, Sweden
| | - Trine Bilde
- Department of Biology, Aarhus University, Aarhus, Denmark
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7
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Busck MM, Lund MB, Bird TL, Bechsgaard JS, Bilde T, Schramm A. Temporal and spatial microbiome dynamics across natural populations of the social spider Stegodyphus dumicola. FEMS Microbiol Ecol 2022; 98:6526868. [PMID: 35147190 DOI: 10.1093/femsec/fiac015] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2021] [Revised: 01/07/2022] [Accepted: 02/09/2022] [Indexed: 11/13/2022] Open
Abstract
Host symbiont interactions may form obligatory or facultative associations that are context dependent. Long-term studies on microbiome composition from wild populations should assess the temporal and spatial dynamics of host-microbe associations. We characterized the temporal and spatial variation in the bacterial microbiome composition in six populations of the social spider Stegodyphus dumicola for 2.5 years, using 16S rRNA gene amplicon sequencing of whole spiders. Individuals within a nest exhibit highly similar microbiomes, which remain stable over several generations and are not predictably affected by seasonal variation in temperature or humidity. This stability in nest microbiome is likely due to social transmission, whereas drift-like processes during new nest foundations explain variation in host microbiomes between nests. This is supported by the lack of obligate symbionts (i.e. no symbionts are present in all spider individuals). Quantitative PCR analyses showed that the bacterial load of individual spiders is stable in healthy nests but can increase dramatically in perishing nests. These increases are not driven by specific bacterial taxa but likely caused by loss of host immune control under deteriorating conditions. Spider nests show an annual survival rate of approximately 45%, but nest death is not correlated to microbiome composition, and the bacteria found in S. dumicola are not considered to be high virulence pathogens.
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Affiliation(s)
- Mette M Busck
- Section for Microbiology, Department of Biology, Aarhus University, Aarhus, Denmark
| | - Marie B Lund
- Section for Microbiology, Department of Biology, Aarhus University, Aarhus, Denmark
| | - Tharina L Bird
- Department of Biological Sciences and Biotechnology, Botswana International University of Science and Technology (BIUST), Botswana.,Section for Genetics, Ecology and Evolution, Department of Biology, Aarhus University, Aarhus, Denmark.,General Entomology, Ditsong National Museum of Natural History, Pretoria, South Africa.,Department of Zoology and Entomology, University of Pretoria, Pretoria, South Africa
| | - Jesper S Bechsgaard
- Section for Genetics, Ecology and Evolution, Department of Biology, Aarhus University, Aarhus, Denmark
| | - Trine Bilde
- Section for Genetics, Ecology and Evolution, Department of Biology, Aarhus University, Aarhus, Denmark
| | - Andreas Schramm
- Section for Microbiology, Department of Biology, Aarhus University, Aarhus, Denmark
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8
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Extended phenotypes can underlie trade-offs: a case of social spiders. THE SCIENCE OF NATURE - NATURWISSENSCHAFTEN 2022; 109:51. [PMID: 36308596 PMCID: PMC9617839 DOI: 10.1007/s00114-022-01826-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/03/2022] [Revised: 09/29/2022] [Accepted: 10/24/2022] [Indexed: 11/30/2022]
Abstract
Extended phenotypes engineered by animals can potentially improve safety and/or foraging. Whether the well-known trade-off between safety and foraging applies for extended phenotypes, and if so, how it is resolved has not been determined. Spiders build elaborate silk structures that serve as traps for their insect prey and often attach silken retreats (nests) to their capture webs. These extended phenotypes of spiders are made of silk that is considered costly since it is made of protein. Using the Indian social spider, Stegodyphus sarasinorum, we examined how simple proximal factors, like colony hunger state and group size, shape trade-offs in collectively built extended phenotypes that offer shelter and food. We found that well-fed colonies showed greater investment in retreat silk than starved colonies. However, the two groups did not differ in their investment in capture webs. Hence, our findings validate the starvation-risk taking hypothesis in an extended phenotypic paradigm by showing that hungry colonies trade-off retreat size for capture web, irrespective of group size.
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9
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Rose C, Schramm A, Irish J, Bilde T, Bird TL. Host Plant Availability and Nest-Site Selection of the Social Spider Stegodyphus dumicola Pocock, 1898 (Eresidae). INSECTS 2021; 13:30. [PMID: 35055873 PMCID: PMC8777811 DOI: 10.3390/insects13010030] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Revised: 12/21/2021] [Accepted: 12/23/2021] [Indexed: 11/16/2022]
Abstract
An animals' habitat defines the resources that are available for its use, such as host plants or food sources, and the use of these resources are critical for optimizing fitness. Spiders are abundant in all terrestrial habitats and are often associated with vegetation, which may provide structure for anchoring capture webs, attract insect prey, or provide protective function. Social spiders construct sedentary communal silk nests on host plants, but we know little about whether and how they make nest-site decisions. We examined host plant use in relation to host plant availability in the social spider Stegodyphus dumicola Pocock, 1898 (Eresidae) across different arid biomes in Namibia and analysed the role of host plant characteristics (height, spines, scent, sturdiness) on nest occurrence. Host plant communities and densities differed between locations. Spider nests were relatively more abundant on Acacia spp., Boscia foetida, Combretum spp., Dichrostachys cinerea, Parkinsonia africana, Tarchonanthus camphoratus, and Ziziphus mucronatus, and nests survived longer on preferred plant genera Acacia, Boscia and Combretum. Spider nests were relatively more abundant on plants higher than 2 m, and on plants with thorns and with a rigid structure. Our results suggest that spiders display differential use of host plant species, and that characteristics such as rigidity and thorns confer benefits such as protection from browsing animals.
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Affiliation(s)
- Clémence Rose
- Department of Biology, Aarhus University, 8000 Aarhus, Denmark; (A.S.); (T.B.); (T.L.B.)
| | - Andreas Schramm
- Department of Biology, Aarhus University, 8000 Aarhus, Denmark; (A.S.); (T.B.); (T.L.B.)
| | - John Irish
- National Museum of Namibia, Windhoek 1005, Namibia;
| | - Trine Bilde
- Department of Biology, Aarhus University, 8000 Aarhus, Denmark; (A.S.); (T.B.); (T.L.B.)
| | - Tharina L. Bird
- Department of Biology, Aarhus University, 8000 Aarhus, Denmark; (A.S.); (T.B.); (T.L.B.)
- General Entomology Section, Ditsong National Museum of Natural History, Pretoria 0002, South Africa
- Department of Zoology and Entomology, University of Pretoria, Private Bag X20, Pretoria 0028, South Africa
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10
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Yip EC, Smith DR, Lubin Y. Long-Term Colony Dynamics and Fitness in a Colonial Tent-Web Spider Cyrtophora citricola. Front Ecol Evol 2021. [DOI: 10.3389/fevo.2021.725647] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Social animals are expected to experience a positive effect of conspecific number or density on fitness (an Allee effect) because of the benefits of group living. However, social animals also often disperse to live either solitarily or in small groups, so to understand why social animals leave their groups it is necessary to understand how group size affects both average fitness and the expected fitness outcomes of individuals. We examined the relationships between group size and fitness in the colonial spider Cyrtophora citricola using long-term observations of colony demographics. We censused colonies, recording the number of juveniles, large females, and egg sacs, approximately every 2 months for 2 years. We also recorded the substrates supporting colony webs, including plant species and size, and the azimuth the colony occupied on the plant. Colonies in all regions showed cyclical patterns of growth and decline; however, regions were not synchronized, and seasonal effects differed between years. Colonies with fewer individuals at the initial observation were less likely to survive over the course of observations, and extinction rates were also influenced by an interaction between region and plant substrate. Small colonies were more likely to be extinct by the next census, but if they survived, they were more likely to have high growth rates compared to larger colonies. Despite the potential for high growth rates, high extinction rates depressed the average fitness of small colonies so that population growth rates peaked at intermediate colony sizes. Variance in egg sac production also peaked at intermediate colony sizes, suggesting that competitive interactions may increase the uneven distribution of resources in larger groups. Even if average fitness is high, if spiders can anticipate poor outcomes in large colonies, they may disperse to live solitarily or in smaller, less competitive groups.
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11
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Fisher DN, Kilgour RJ, Siracusa ER, Foote JR, Hobson EA, Montiglio PO, Saltz JB, Wey TW, Wice EW. Anticipated effects of abiotic environmental change on intraspecific social interactions. Biol Rev Camb Philos Soc 2021; 96:2661-2693. [PMID: 34212487 DOI: 10.1111/brv.12772] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2019] [Revised: 06/18/2021] [Accepted: 06/21/2021] [Indexed: 12/30/2022]
Abstract
Social interactions are ubiquitous across the animal kingdom. A variety of ecological and evolutionary processes are dependent on social interactions, such as movement, disease spread, information transmission, and density-dependent reproduction and survival. Social interactions, like any behaviour, are context dependent, varying with environmental conditions. Currently, environments are changing rapidly across multiple dimensions, becoming warmer and more variable, while habitats are increasingly fragmented and contaminated with pollutants. Social interactions are expected to change in response to these stressors and to continue to change into the future. However, a comprehensive understanding of the form and magnitude of the effects of these environmental changes on social interactions is currently lacking. Focusing on four major forms of rapid environmental change currently occurring, we review how these changing environmental gradients are expected to have immediate effects on social interactions such as communication, agonistic behaviours, and group formation, which will thereby induce changes in social organisation including mating systems, dominance hierarchies, and collective behaviour. Our review covers intraspecific variation in social interactions across environments, including studies in both the wild and in laboratory settings, and across a range of taxa. The expected responses of social behaviour to environmental change are diverse, but we identify several general themes. First, very dry, variable, fragmented, or polluted environments are likely to destabilise existing social systems. This occurs as these conditions limit the energy available for complex social interactions and affect dissimilar phenotypes differently. Second, a given environmental change can lead to opposite responses in social behaviour, and the direction of the response often hinges on the natural history of the organism in question. Third, our review highlights the fact that changes in environmental factors are not occurring in isolation: multiple factors are changing simultaneously, which may have antagonistic or synergistic effects, and more work should be done to understand these combined effects. We close by identifying methodological and analytical techniques that might help to study the response of social interactions to changing environments, highlight consistent patterns among taxa, and predict subsequent evolutionary change. We expect that the changes in social interactions that we document here will have consequences for individuals, groups, and for the ecology and evolution of populations, and therefore warrant a central place in the study of animal populations, particularly in an era of rapid environmental change.
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Affiliation(s)
- David N Fisher
- School of Biological Sciences, University of Aberdeen, King's College, Aberdeen, AB24 3FX, U.K
| | - R Julia Kilgour
- Department of Animal Sciences, Purdue University, West Lafayette, IN, 47907, U.S.A
| | - Erin R Siracusa
- Centre for Research in Animal Behaviour, School of Psychology, University of Exeter, Stocker Road, Exeter, EX4 4PY, U.K
| | - Jennifer R Foote
- Department of Biology, Algoma University, 1520 Queen Street East, Sault Ste. Marie, ON, P6A 2G4, Canada
| | - Elizabeth A Hobson
- Department of Biological Sciences, University of Cincinnati, 318 College Drive, Cincinnati, OH, 45221, U.S.A
| | - Pierre-Olivier Montiglio
- Département des Sciences Biologiques, Université du Québec à Montréal, 141 Avenue Président-Kennedy, Montréal, QC, H2X 3X8, Canada
| | - Julia B Saltz
- Department of Biosciences, Rice University, 6100 Main Street, Houston, TX, 77005-1827, U.S.A
| | - Tina W Wey
- Maelstrom Research, The Research Institute of the McGill University Health Centre, Montreal General Hospital, 1650 Cedar Avenue, Montréal, QC, H3G 1A4, Canada
| | - Eric W Wice
- Department of Biosciences, Rice University, 6100 Main Street, Houston, TX, 77005-1827, U.S.A
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12
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Bai Z, Liu Y, Sillam‐Dussès D, Wang R. Experimentally measured group direct benefits according to worker density explain group living of the termite Reticulitermes chinensis. Ecol Evol 2021; 11:8768-8775. [PMID: 34257926 PMCID: PMC8258223 DOI: 10.1002/ece3.7685] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2021] [Revised: 04/05/2021] [Accepted: 04/20/2021] [Indexed: 11/11/2022] Open
Abstract
The evolution of cooperation requires more benefits of group living than solitary lifestyle. However, to some degree, our understanding about the benefits is hindered by abstract debates over theoretical and experimental evidences of individual selection or group selection because it is difficult to examine the actual benefits at the group level. Moreover, group density is a crucial ecological factor which deeply affects group reproduction and survival, few studies have been performed in social insects. Here, we study the effects of worker density on group direct benefits in the termite species Reticulitermes chinensis. The termite R. chinensis is an ideal model which lives with a high worker density in wood. We used the quantity of eggs and the total biomass (biomass of all group members) accumulation as two components of group benefits. We investigated the group benefits in the context of worker density according to eleven worker densities, and we measured the group benefits and the resource consumption with the same group members in two types of artificial nest areas. Moreover, we counted the stomodeal trophallaxis occurrences from any workers to queens under three worker densities to explore the degree of cooperation according to worker density. We found that both the number of eggs and the total biomass accumulation significantly increased with increasing worker density in groups. Furthermore, the consumption of resources was similar between groups with the same number of individuals gathered in small or large nest areas, but the production of eggs and the biomass accumulation were higher in groups of small nest areas than in large nest areas. Additionally, we found the stomodeal trophallaxis behavior significantly increased in higher worker density groups. Our results suggest that the group benefits influenced by the high worker density may at least partially explain the group living of eusocial insects in ecology.
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Affiliation(s)
- Zhuangdong Bai
- School of Ecology and EnvironmentNorthwestern Polytechnical UniversityXi’anChina
| | - Yibin Liu
- School of Ecology and EnvironmentNorthwestern Polytechnical UniversityXi’anChina
| | - David Sillam‐Dussès
- Laboratory of Experimental and Comparative Ethology UR4443University Sorbonne Paris NordVilletaneuseFrance
| | - Rui‐Wu Wang
- School of Ecology and EnvironmentNorthwestern Polytechnical UniversityXi’anChina
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13
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Anderson HM, Little AG, Fisher DN, McEwen BL, Culbert BM, Balshine S, Pruitt JN. Behavioral and physiological evidence that increasing group size ameliorates the impacts of social disturbance. J Exp Biol 2020; 223:jeb217075. [PMID: 32532861 DOI: 10.1242/jeb.217075] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2019] [Accepted: 06/04/2020] [Indexed: 12/19/2022]
Abstract
Intra-group social stability is important for the long-term productivity and health of social organisms. We evaluated the effect of group size on group stability in the face of repeated social perturbations using a cooperatively breeding fish, Neolamprologus pulcher In a laboratory study, we compared both the social and physiological responses of individuals from small versus large groups to the repeated removal and replacement of the most dominant group member (the breeder male), either with a new male (treatment condition) or with the same male (control condition). Individuals living in large groups were overall more resistant to instability but were seemingly slower to recover from perturbation. Members of small groups were more vulnerable to instability but recovered faster. Breeder females in smaller groups also showed greater physiological preparedness for instability following social perturbations. In sum, we discover both behavioral and physiological evidence that living in larger groups helps to dampen the impacts of social instability in this system.
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Affiliation(s)
- Hannah M Anderson
- Department of Psychology, Neuroscience & Behaviour, McMaster University, Hamilton, ON, Canada L8S 4K1
| | - Alexander G Little
- Department of Psychology, Neuroscience & Behaviour, McMaster University, Hamilton, ON, Canada L8S 4K1
- Marine Science Institute, University of California Santa Barbara, Santa Barbara, CA 93106, USA
| | - David N Fisher
- Department of Psychology, Neuroscience & Behaviour, McMaster University, Hamilton, ON, Canada L8S 4K1
| | - Brendan L McEwen
- Department of Psychology, Neuroscience & Behaviour, McMaster University, Hamilton, ON, Canada L8S 4K1
| | - Brett M Culbert
- Department of Integrative Biology, University of Guelph, Guelph, ON, Canada N1G 2W1
| | - Sigal Balshine
- Department of Psychology, Neuroscience & Behaviour, McMaster University, Hamilton, ON, Canada L8S 4K1
| | - Jonathan N Pruitt
- Department of Psychology, Neuroscience & Behaviour, McMaster University, Hamilton, ON, Canada L8S 4K1
- Marine Science Institute, University of California Santa Barbara, Santa Barbara, CA 93106, USA
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14
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Mutz J, Underwood N, Inouye BD. Integrating top-down and bottom-up effects of local density across scales and a complex life cycle. Ecology 2020; 101:e03118. [PMID: 32531072 DOI: 10.1002/ecy.3118] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/04/2019] [Revised: 03/25/2020] [Accepted: 05/06/2020] [Indexed: 11/06/2022]
Abstract
Effects of group size (local conspecific density) on individual performance can be substantial, yet it is unclear how these translate to larger-scale and longer-term outcomes. Effects of group size can be mediated by both top-down and bottom-up interactions, can change in type or direction across the life cycle, and can depend on the spatial scale at which group size is assessed. Only by determining how these different processes combine can we make predictions about how selection operates on group size or link hierarchical patterns of density dependence with population dynamics. We manipulated the density of a leaf beetle, Leptinotarsa juncta, at three nested spatial scales (patch, plant within a patch, and leaf within plant) to investigate how conspecific density affects predator-mediated survival and resource-mediated growth during different life stages and across multiple spatial scales. We then used data from field predation experiments to assess how L. juncta densities at hierarchical scales affect different aspects of predation. Finally, we incorporated predator- and resource-mediated effects of density in a model to explore how changes in group size due to density-dependent predation might affect mass at pupation for survivors. The effects of L. juncta density on predation risk differed among scales. Per capita predation risk of both eggs and late instars was lowest at high patch-scale densities, but increased with plant-scale density. The final mass of late instars declined with increasing plant-scale larval density, potentially because of truncated development of high-density larvae. Predation incidence (i.e., group attack rate) increased with larval density at all spatial scales. A high coefficient of variation (i.e., greater aggregation) of L. juncta density was associated with lower predation incidence at some scales. Our model suggested that predator- and resource-mediated effects of density interact: lower survival at high larval density is mitigated by high final mass of larvae in the resulting smaller groups. Our results emphasize the importance of spatial scale and demonstrate that effects of top-down and bottom-up interactions are not necessarily independent. To understand how group size influences fitness, predator- and resource-mediated effects of density should be measured in their demographic and spatial context, and not in isolation.
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Affiliation(s)
- Jessie Mutz
- Department of Biological Science, Florida State University, Tallahassee, Florida, 32306, USA
| | - Nora Underwood
- Department of Biological Science, Florida State University, Tallahassee, Florida, 32306, USA
| | - Brian D Inouye
- Department of Biological Science, Florida State University, Tallahassee, Florida, 32306, USA
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15
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Guindre-Parker S, Rubenstein DR. Survival Benefits of Group Living in a Fluctuating Environment. Am Nat 2020; 195:1027-1036. [PMID: 32469654 DOI: 10.1086/708496] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
Group living is predicted to arise only when the fitness benefits outweigh the costs of sociality. Group-living species-including cooperatively breeding and family-living birds and mammals-occur most frequently in environments where climatic conditions fluctuate unpredictably from year to year. The fitness consequences of group living are thus expected to vary with changing environmental conditions, though few studies have examined this possibility. We examined whether living in large social groups improves adult survivorship in cooperatively breeding superb starlings (Lamprotornis superbus). We also tested the hypothesis that larger groups buffer against harsh conditions by increasing survivorship most under periods of low rainfall. We found that group size was positively correlated with adult survival but in a sex-specific manner: female survival increased with group size across all environmental conditions, whereas male survival increased with group size only in wet years. Together with previous work in this system, our results suggest that larger groups confer survival benefits by reducing predation, rather than by improving access to food or buffering against physiological stress. Although group living does not appear to buffer against harsh conditions in adult starlings living in a fluctuating environment, living in larger groups does confer a survival advantage.
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16
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Fisher DN, Lichtenstein JLL, Costa-Pereira R, Yeager J, Pruitt JN. Assessing the repeatability, robustness to disturbance, and parent-offspring colony resemblance of collective behavior. J Evol Biol 2019; 33:410-421. [PMID: 31821669 DOI: 10.1111/jeb.13576] [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: 09/17/2019] [Accepted: 12/04/2019] [Indexed: 11/27/2022]
Abstract
Groups of animals possess phenotypes such as collective behaviour, which may determine the fitness of group members. However, the stability and robustness to perturbations of collective phenotypes in natural conditions is not established. Furthermore, whether group phenotypes are transmitted from parent to offspring groups with fidelity is required for understanding how selection on group phenotypes contributes to evolution, but parent-offspring resemblance at the group level is rarely estimated. We evaluated the repeatability, robustness to perturbation and parent-offspring resemblance of collective foraging aggressiveness in colonies of the social spider Anelosimus eximius. Among-colony differences in foraging aggressiveness were consistent over time but changed if the colony was perturbed through the removal of individuals or via individuals' removal and subsequent return. Offspring and parent colony behaviour were correlated at the phenotypic level, but only once the offspring colony had settled after being translocated, and the correlation overlapped with zero at the among-colony level. The parent-offspring resemblance was not driven by a shared elevation but could be due to other environmental factors. The behaviour of offspring colonies in a common garden laboratory setting was not correlated with the behaviour of the parent colony nor with the same colony's behaviour once it was returned to the field. The phenotypes of groups represent a potentially important tier of biological organization, and assessing the stability and heritability of such phenotypes helps us better understand their role in evolution.
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Affiliation(s)
- David N Fisher
- Department of Psychology, Neuroscience and Behaviour, McMaster University, Hamilton, ON, Canada
| | - James L L Lichtenstein
- Department of Ecology, Evolution and Marine Biology, University of California - Santa Barbara, Santa Barbara, CA, USA
| | - Raul Costa-Pereira
- Department of Psychology, Neuroscience and Behaviour, McMaster University, Hamilton, ON, Canada.,Departamento de Biologia Animal, Instituto de Biologia, Universidade Estadual de Campinas (UNICAMP), Campinas, São Paulo, Brazil
| | - Justin Yeager
- Biodiversidad Medio Ambiente y Salud (BIOMAS), Direccion General de Investigacion, Universidad de las Américas, Quito, Ecuador
| | - Jonathan N Pruitt
- Department of Psychology, Neuroscience and Behaviour, McMaster University, Hamilton, ON, Canada.,Department of Ecology, Evolution and Marine Biology, University of California - Santa Barbara, Santa Barbara, CA, USA
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17
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Grinsted L, Schou MF, Settepani V, Holm C, Bird TL, Bilde T. Prey to predator body size ratio in the evolution of cooperative hunting-a social spider test case. Dev Genes Evol 2019; 230:173-184. [PMID: 31768622 DOI: 10.1007/s00427-019-00640-w] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2019] [Accepted: 10/30/2019] [Indexed: 11/30/2022]
Abstract
One of the benefits of cooperative hunting may be that predators can subdue larger prey. In spiders, cooperative, social species can capture prey many times larger than an individual predator. However, we propose that cooperative prey capture does not have to be associated with larger caught prey per se, but with an increase in the ratio of prey to predator body size. This can be achieved either by catching larger prey while keeping predator body size constant, or by evolving a smaller predator body size while maintaining capture of large prey. We show that within a genus of relatively large spiders, Stegodyphus, subsocial spiders representing the ancestral state of social species are capable of catching the largest prey available in the environment. Hence, within this genus, the evolution of cooperation would not provide access to otherwise inaccessible, large prey. Instead, we show that social Stegodyphus spiders are smaller than their subsocial counterparts, while catching similar sized prey, leading to the predicted increase in prey-predator size ratio with sociality. We further show that in a genus of small spiders, Anelosimus, the level of sociality is associated with an increased size of prey caught while predator size is unaffected by sociality, leading to a similar, predicted increase in prey-predator size ratio. In summary, we find support for our proposed 'prey to predator size ratio hypothesis' and discuss how relaxed selection on large body size in the evolution of social, cooperative living may provide adaptive benefits for ancestrally relatively large predators.
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Affiliation(s)
- Lena Grinsted
- School of Biological Sciences, Royal Holloway University of London, Egham, Surrey, TW20 0EX, UK
| | - Mads F Schou
- Department of Biology, Lund University, 22362, Lund, Sweden
| | - Virginia Settepani
- Department of Biology, Aarhus University, Ny Munkegade 114-116, 8000, Aarhus C, Denmark
| | - Christina Holm
- Department of Biology, Aarhus University, Ny Munkegade 114-116, 8000, Aarhus C, Denmark
| | - Tharina L Bird
- Department of Biological Sciences and Biotechnology, Botswana International University of Science and Technology (BIUST), Plot, 10071, Palapye, Botswana
| | - Trine Bilde
- Department of Biology, Aarhus University, Ny Munkegade 114-116, 8000, Aarhus C, Denmark.
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18
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Lichtenstein JLL, Fisher DN, McEwen BL, Nondorf DT, Calvache E, Schmitz C, Elässer J, Pruitt JN. Collective aggressiveness limits colony persistence in high- but not low-elevation sites at Amazonian social spiders. J Evol Biol 2019; 32:1362-1367. [PMID: 31464022 DOI: 10.1111/jeb.13532] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2019] [Revised: 08/10/2019] [Accepted: 08/22/2019] [Indexed: 11/25/2022]
Abstract
Identifying the traits that foster group survival in contrasting environments is important for understanding local adaptation in social systems. Here, we evaluate the relationship between the aggressiveness of social spider colonies and their persistence along an elevation gradient using the Amazonian spider, Anelosimus eximius. We found that colonies of A. eximius exhibit repeatable differences in their collective aggressiveness (latency to attack prey stimuli) and that colony aggressiveness is linked with persistence in a site-specific manner. Less aggressive colonies are better able to persist at high-elevation sites, which lack colony-sustaining large-bodied prey, whereas colony aggression was not related to chance of persistence at low-elevation sites. This suggests that low aggressiveness promotes colony survival in high-elevation, prey-poor habitats, perhaps via increased tolerance to resource limitation. These data reveal that the collective phenotypes that relate to colony persistence vary by site, and thus, the path of social evolution in these environments is likely to be affected.
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Affiliation(s)
- James L L Lichtenstein
- Department of Ecology, Evolution & Marine Biology, University of California - Santa Barbara, Santa Barbara, CA, USA
| | - David N Fisher
- Department of Psychology, Neuroscience & Behaviour, McMaster University, Hamilton, ON, Canada
| | - Brendan L McEwen
- Department of Psychology, Neuroscience & Behaviour, McMaster University, Hamilton, ON, Canada
| | - Daniel T Nondorf
- Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, MI, USA
| | - Esteban Calvache
- Department of Biology, Pontifica Universidad Católica del Ecuador, Quito, Ecuador
| | | | | | - Jonathan N Pruitt
- Department of Ecology, Evolution & Marine Biology, University of California - Santa Barbara, Santa Barbara, CA, USA.,Department of Psychology, Neuroscience & Behaviour, McMaster University, Hamilton, ON, Canada
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19
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Junghanns A, Holm C, Schou MF, Overgaard J, Malte H, Uhl G, Bilde T. Physiological Adaptations to Extreme Maternal and Allomaternal Care in Spiders. Front Ecol Evol 2019. [DOI: 10.3389/fevo.2019.00305] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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20
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Berkowic D, Markman S. Weighing density and kinship: Aggressive behavior and time allocation in fire salamander (Salamandra infraimmaculata). PLoS One 2019; 14:e0220499. [PMID: 31381581 PMCID: PMC6681942 DOI: 10.1371/journal.pone.0220499] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2018] [Accepted: 07/17/2019] [Indexed: 12/02/2022] Open
Abstract
Kin-biased behavior (that is responding differentially to kin and non-kin) is thought to be adaptive in many social interactions. One example of this kin bias is behaving less aggressively toward a relative than a non-relative, a behavior which yields inclusive fitness benefits. However, data are lacking about the ability of animals to weigh their preference for kinship and the density of conspecifics simultaneously and to respond accordingly. Fire salamanders (Salamandra infraimmaculata) larviposit in high densities in ponds. Thus, larvae of different females confront competition and predation by other larvae. We studied whether larvae prefer their kin over particular density or vice versa. We experimentally used a transparent glass aquarium with inner chambers to test the responses of a focal larva toward its siblings and non-siblings. Specifically, we quantified the time a focal larva spent near its siblings or non-siblings, presented in varying densities, and the aggression level it demonstrated. We found that focal larvae spent more time near non-siblings if non-sibling and sibling groups were of equal density. The focal larvae were also more aggressive toward non-siblings. The results may be explained by the cannibalistic nature of these larvae: high density may provide more opportunities for food, especially when non-siblings are present. Further explanations for these findings may include other advantages of staying in a larger group and/or the stronger olfactory and visual stimulation offered by groups compared to a single individual. These findings suggest that larvae make differential responses toward conspecifics depending simultaneously on the level of relatedness and the density of the group. Such responses have important implications for social—aggregation decisions and may especially affect the fitness of cannibalistic species.
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Affiliation(s)
- Daniel Berkowic
- Department of Biology & Environment, Faculty of Natural Sciences, University of Haifa–Oranim, Tivon, Israel
| | - Shai Markman
- Department of Biology & Environment, Faculty of Natural Sciences, University of Haifa–Oranim, Tivon, Israel
- * E-mail:
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21
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Bechsgaard J, Schou MF, Vanthournout B, Hendrickx F, Knudsen B, Settepani V, Schierup MH, Bilde T. Evidence for Faster X Chromosome Evolution in Spiders. Mol Biol Evol 2019; 36:1281-1293. [PMID: 30912801 PMCID: PMC6526907 DOI: 10.1093/molbev/msz074] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
In species with chromosomal sex determination, X chromosomes are predicted to evolve faster than autosomes because of positive selection on recessive alleles or weak purifying selection. We investigated X chromosome evolution in Stegodyphus spiders that differ in mating system, sex ratio, and population dynamics. We assigned scaffolds to X chromosomes and autosomes using a novel method based on flow cytometry of sperm cells and reduced representation sequencing. We estimated coding substitution patterns (dN/dS) in a subsocial outcrossing species (S. africanus) and its social inbreeding and female-biased sister species (S. mimosarum), and found evidence for faster-X evolution in both species. X chromosome-to-autosome diversity (piX/piA) ratios were estimated in multiple populations. The average piX/piA estimates of S. africanus (0.57 [95% CI: 0.55-0.60]) was lower than the neutral expectation of 0.75, consistent with more hitchhiking events on X-linked loci and/or a lower X chromosome mutation rate, and we provide evidence in support of both. The social species S. mimosarum has a significantly higher piX/piA ratio (0.72 [95% CI: 0.65-0.79]) in agreement with its female-biased sex ratio. Stegodyphus mimosarum also have different piX/piA estimates among populations, which we interpret as evidence for recurrent founder events. Simulations show that recurrent founder events are expected to decrease the piX/piA estimates in S. mimosarum, thus underestimating the true effect of female-biased sex ratios. Finally, we found lower synonymous divergence on X chromosomes in both species, and the male-to-female substitution ratio to be higher than 1, indicating a higher mutation rate in males.
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Affiliation(s)
| | - Mads Fristrup Schou
- Department of Bioscience, Aarhus University, Aarhus C, Denmark.,Department of Biology, Lund University, SE-223 62 Lund, Sweden
| | - Bram Vanthournout
- Department of Bioscience, Aarhus University, Aarhus C, Denmark.,Evolution and Optics of Nanostructure Group (EON), Biology Department, Ghent University, Ghent, Belgium
| | - Frederik Hendrickx
- Royal Belgian Institute of Natural Sciences, Brussels, Belgium.,Terrestrial Ecology Unit (TEREC), Biology Department, Ghent University, Ghent, Belgium
| | | | | | - Mikkel Heide Schierup
- Department of Bioscience, Aarhus University, Aarhus C, Denmark.,Bioinformatics Research Centre (BiRC), Aarhus University, Aarhus C, Denmark
| | - Trine Bilde
- Department of Bioscience, Aarhus University, Aarhus C, Denmark
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22
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Hunt ER, Mi B, Geremew R, Fernandez C, Wong BM, Pruitt JN, Pinter-Wollman N. Resting networks and personality predict attack speed in social spiders. Behav Ecol Sociobiol 2019; 73. [PMID: 32440036 DOI: 10.1007/s00265-019-2715-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Groups of social predators capture large prey items collectively, and their social interaction patterns may impact how quickly they can respond to time-sensitive predation opportunities. We investigated whether various organizational levels of resting interactions (individual, sub-group, group), observed at different intervals leading up to a collective prey attack, impacted the predation speed of colonies of the social spider Stegodyphus dumicola. We found that in adult spiders, overall group connectivity (average degree) increased group attack speed. However, this effect was detected only immediately before the predation event; connectivity between 2 and 4 days before prey capture had little impact on the collective dynamics. Significantly, lower social proximity of the group's boldest individual to other group members (closeness centrality) immediately prior and 2 days before prey capture was associated with faster attack speeds. These results suggest that for adult spiders, the long-lasting effects of the boldest individual on the group's attack dynamics are mediated by its role in the social network, and not only by its boldness. This suggests that behavioural traits and social network relationships should be considered together when defining keystone individuals in some contexts. By contrast, for subadult spiders, while the group maximum boldness was negatively correlated with latency to attack, no significant resting network predictors of latency to attack were found. Thus, separate behavioural mechanisms might play distinctive roles in determining collective outcomes at different developmental stages, timescales, and levels of social organization.
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Affiliation(s)
- Edmund R Hunt
- Department of Ecology and Evolutionary Biology, University of California, Los Angeles, CA 90095, USA
| | - Brian Mi
- BioCircuits Institute, University of California, San Diego, La Jolla, CA 92093, USA
| | - Rediet Geremew
- BioCircuits Institute, University of California, San Diego, La Jolla, CA 92093, USA
| | - Camila Fernandez
- BioCircuits Institute, University of California, San Diego, La Jolla, CA 92093, USA
| | - Brandyn M Wong
- BioCircuits Institute, University of California, San Diego, La Jolla, CA 92093, USA
| | - Jonathan N Pruitt
- Department of Ecology, Evolution, and Marine Biology, University of California, Santa Barbara, CA 93106, USA
| | - Noa Pinter-Wollman
- Department of Ecology and Evolutionary Biology, University of California, Los Angeles, CA 90095, USA
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23
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Draft Genome Sequence of Bacillus subtilis SB-14, an Antimicrobially Active Isolate from Namibian Social Spiders (
Stegodyphus dumicola
). Microbiol Resour Announc 2019; 8:8/25/e00156-19. [PMID: 31221641 PMCID: PMC6588362 DOI: 10.1128/mra.00156-19] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We present the high-quality draft genome sequence of
Bacillus subtilis
SB-14, isolated from the Namibian social spider
Stegodyphus dumicola
. In accordance with its antimicrobial activity, both known and potentially novel antimicrobial biosynthetic gene clusters were identified in the genome of SB-14.
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24
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De Bona S, Bruneaux M, Lee AEG, Reznick DN, Bentzen P, López‐Sepulcre A. Spatio‐temporal dynamics of density‐dependent dispersal during a population colonisation. Ecol Lett 2019; 22:634-644. [DOI: 10.1111/ele.13205] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2018] [Revised: 08/30/2018] [Accepted: 11/15/2018] [Indexed: 11/28/2022]
Affiliation(s)
- Sebastiano De Bona
- University of Jyväskylä Centre of Excellence in Biological Interactions Department of Biological and Environmental Science Jyväskylä Finland
| | - Matthieu Bruneaux
- University of Jyväskylä Centre of Excellence in Biological Interactions Department of Biological and Environmental Science Jyväskylä Finland
| | - Alex E. G. Lee
- University of Jyväskylä Centre of Excellence in Biological Interactions Department of Biological and Environmental Science Jyväskylä Finland
| | | | - Paul Bentzen
- Department of Biology Dalhousie University Halifax Canada
| | - Andrés López‐Sepulcre
- University of Jyväskylä Centre of Excellence in Biological Interactions Department of Biological and Environmental Science Jyväskylä Finland
- CNRS UMR 7618 Institute of Ecology and Environmental Sciences Paris (iEES) Sorbonne University Paris France
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25
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Murali G, Kumari K, Kodandaramaiah U. Dynamic colour change and the confusion effect against predation. Sci Rep 2019; 9:274. [PMID: 30670756 PMCID: PMC6342951 DOI: 10.1038/s41598-018-36541-7] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2018] [Accepted: 11/22/2018] [Indexed: 11/09/2022] Open
Abstract
The confusion effect - the decreased attack-to-kill ratio of a predator with increase in prey group size - is thought to be one of the main reasons for the evolution of group living in animals. Despite much interest, the influence of prey coloration on the confusion effect is not well understood. We hypothesized that dynamic colour change in motion (due to interference coloration or flash marks), seen widely in many group living animals, enhances the confusion effect. Utilizing a virtual tracking task with humans, we found targets that dynamically changed colour during motion were more difficult to track than targets with background matching patterns, and this effect was stronger at larger group sizes. The current study thus provides the first empirical evidence for the idea that dynamic colour change can benefit animals in a group and may explain the widespread occurrence of dynamic colorations in group-living animals.
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Affiliation(s)
- Gopal Murali
- IISER-TVM Centre for Research and Education in Ecology and Evolution (ICREEE), School of Biology, Indian Institute of Science Education and Research Thiruvananthapuram, Maruthamala PO, Vithura, Thiruvananthapuram, 695 551, India.
| | - Kajal Kumari
- IISER-TVM Centre for Research and Education in Ecology and Evolution (ICREEE), School of Biology, Indian Institute of Science Education and Research Thiruvananthapuram, Maruthamala PO, Vithura, Thiruvananthapuram, 695 551, India
| | - Ullasa Kodandaramaiah
- IISER-TVM Centre for Research and Education in Ecology and Evolution (ICREEE), School of Biology, Indian Institute of Science Education and Research Thiruvananthapuram, Maruthamala PO, Vithura, Thiruvananthapuram, 695 551, India
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26
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Kamath A, Primavera SD, Wright CM, Doering GN, Sheehy KA, Pinter-Wollman N, Pruitt JN. Collective behavior and colony persistence of social spiders depends on their physical environment. Behav Ecol 2019; 30:39-47. [PMID: 30846891 PMCID: PMC6398429 DOI: 10.1093/beheco/ary158] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2018] [Revised: 10/16/2018] [Accepted: 11/06/2018] [Indexed: 12/18/2022] Open
Abstract
The physical environment occupied by group-living animals can profoundly affect their cooperative social interactions and therefore their collective behavior and success. These effects can be especially apparent in human-modified habitats, which often harbor substantial variation in the physical environments available within them. For nest-building animal societies, this influence of the physical environment on collective behavior can be mediated by the construction of nests-nests could either buffer animal behavior from changes in the physical environment or facilitate shifts in behavior through changes in nest structure. We test these alternative hypotheses by examining the differences in collective prey-attacking behavior and colony persistence between fence-dwelling and tree-dwelling colonies of Stegodyphus dumicola social spiders. Fences and trees represent substantially different physical environments: fences are 2-dimensional and relatively homogenous environments, whereas tree branches are 3-dimensional and relatively heterogeneous. We found that fence-dwelling colonies attack prey more quickly and with more attackers than tree-dwelling colonies in both field and controlled settings. Moreover, in the field, fence-dwelling colonies captured more prey, were more likely to persist, and had a greater number of individuals remaining at the end of the experiment than tree-dwelling colonies. Intriguingly, we also observed a greater propensity for colony fragmentation in tree-dwelling colonies than fence-dwelling colonies. Our results demonstrate that the physical environment is an important influence on the collective behavior and persistence of colonies of social spiders, and suggest multiple possible proximate and ultimate mechanisms-including variation in web complexity, dispersal behavior, and bet-hedging-by which this influence may be realized.
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Affiliation(s)
- Ambika Kamath
- Department of Ecology, Evolution, and Marine Biology, University of California Santa Barbara, Santa Barbara, CA, USA
- Department of Environmental Science, Policy, and Management & Miller Institute for Basic Research in Science, University of California Berkeley, Berkeley, CA, USA
| | - Skylar D Primavera
- Department of Ecology, Evolution, and Marine Biology, University of California Santa Barbara, Santa Barbara, CA, USA
| | - Colin M Wright
- Department of Ecology, Evolution, and Marine Biology, University of California Santa Barbara, Santa Barbara, CA, USA
- Department of Biology, Pennsylvania State University, University Park, PA, USA
| | - Grant N Doering
- Department of Ecology, Evolution, and Marine Biology, University of California Santa Barbara, Santa Barbara, CA, USA
| | - Kirsten A Sheehy
- Department of Ecology, Evolution, and Marine Biology, University of California Santa Barbara, Santa Barbara, CA, USA
| | - Noa Pinter-Wollman
- Department of Ecology & Evolutionary Biology, University of California Los Angeles, Los Angeles, CA, USA
| | - Jonathan N Pruitt
- Department of Ecology, Evolution, and Marine Biology, University of California Santa Barbara, Santa Barbara, CA, USA
- Department of Psychology, Neuroscience & Behaviour, McMaster University, Hamilton, Ontario Canada
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27
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Lichtenstein JLL, Kamath A, Bengston S, Avilés L, Pruitt JN. Female-Biased Sex Ratios Increase Colony Survival and Reproductive Output in the Spider Anelosimus studiosus. Am Nat 2018; 192:552-563. [PMID: 30332581 DOI: 10.1086/699838] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
Negative frequency-dependent selection acting on the sexes is hypothesized to drive populations toward a balanced sex ratio. However, numerous examples of female-biased sex ratios pepper the arthropods. Theoretical examinations have proposed that female-biased populations or groups can have higher chances of surviving and propagating that may be advantageous. We evaluated this hypothesis in the semisocial spider Anelosimus studiosus by creating artificial colonies of varying sex ratios and sizes and observing colony performance at sites with high versus low group extinction rates. We also tested whether colony extinction rates and sex ratios were correlated across 25 collection sites, spanning 10° latitude. We found that colonies with female-biased sex ratios produced more egg cases and were more likely to survive the duration of a field season, suggesting that female-biased sex ratios confer both survival and reproductive advantages on colonies. The effect of sex ratio on colony survival and reproductive output was strongest for small colonies in high extinction areas. Moreover, we found that female-biased sex ratios correlated with greater extinction rates across 25 sites, indicating that female-biased sex ratios may have evolved at some sites in response to high extinction rates. These findings suggest that selection favoring groups with female-biased sex ratios may operate in A. studiosus, shedding light on some of the factors that may drive the evolution of biased sex ratios.
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Hunt ER, Mi B, Fernandez C, Wong BM, Pruitt JN, Pinter-Wollman N. Social interactions shape individual and collective personality in social spiders. Proc Biol Sci 2018; 285:20181366. [PMID: 30185649 PMCID: PMC6158534 DOI: 10.1098/rspb.2018.1366] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2018] [Accepted: 08/09/2018] [Indexed: 11/12/2022] Open
Abstract
The behavioural composition of a group and the dynamics of social interactions can both influence how social animals work collectively. For example, individuals exhibiting certain behavioural tendencies may have a disproportionately large impact on the group, and so are referred to as keystone individuals, while interactions between individuals can facilitate information transmission about resources. Despite the potential impact of both behavioural composition and interactions on collective behaviour, the relationship between consistent behaviours (also known as personalities) and social interactions remains poorly understood. Here, we use stochastic actor-oriented models to uncover the interdependencies between boldness and social interactions in the social spider Stegodyphus dumicola We find that boldness has no effect on the likelihood of forming social interactions, but interactions do affect boldness, and lead to an increase in the boldness of the shyer individual. Furthermore, spiders tend to interact with the same individuals as their neighbours. In general, boldness decreases over time, but once an individual's boldness begins to increase, this increase accelerates, suggesting a positive feedback mechanism. These dynamics of interactions and boldness result in skewed boldness distributions of a few bold individuals and many shy individuals, as observed in nature. This group behavioural composition facilitates efficient collective behaviours, such as rapid collective prey attack. Thus, by examining the relationship between behaviour and interactions, we reveal the mechanisms that underlie the emergence of adaptive group composition and collective behaviour.
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Affiliation(s)
- Edmund R Hunt
- Department of Ecology and Evolutionary Biology, University of California, Los Angeles, CA 90095, USA
| | - Brian Mi
- BioCircuits Institute, University of California, San Diego, La Jolla, CA 92093, USA
| | - Camila Fernandez
- BioCircuits Institute, University of California, San Diego, La Jolla, CA 92093, USA
| | - Brandyn M Wong
- BioCircuits Institute, University of California, San Diego, La Jolla, CA 92093, USA
| | - Jonathan N Pruitt
- Department of Ecology, Evolution, and Marine Biology, University of California, Santa Barbara, CA 93106, USA
| | - Noa Pinter-Wollman
- Department of Ecology and Evolutionary Biology, University of California, Los Angeles, CA 90095, USA
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Majer M, Holm C, Lubin Y, Bilde T. Cooperative foraging expands dietary niche but does not offset intra-group competition for resources in social spiders. Sci Rep 2018; 8:11828. [PMID: 30087391 PMCID: PMC6081395 DOI: 10.1038/s41598-018-30199-x] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2017] [Accepted: 07/06/2018] [Indexed: 11/23/2022] Open
Abstract
Group living animals invariably risk resource competition. Cooperation in foraging, however, may benefit individuals in groups by facilitating an increase in dietary niche. To test this, we performed a comparative study of social and solitary spider species. Three independently derived social species of Stegodyphus (Eresidae) occupy semi-arid savannas and overlap with three solitary congeners. We estimated potential prey availability in the environment and prey acquisition by spiders in their capture webs. We calculated dietary niche width (prey size) and breadth (taxonomic range) to compare resource use for these six species, and investigated the relationships between group size and average individual capture web production, prey biomass intake rate and variance in biomass intake. Cooperative foraging increased dietary niche width and breadth by foraging opportunistically, including both larger prey and a wider taxonomic range of prey in the diet. Individual capture web production decreased with increasing group size, indicating energetic benefits of cooperation, and variance in individual intake rate was reduced. However, individual biomass intake also decreased with increasing group size. While cooperative foraging did not completely offset resource competition among group members, it may contribute to sustaining larger groups by reducing costs of web production, increasing the dietary niche and reducing the variance in prey capture.
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Affiliation(s)
- Marija Majer
- Blaustein Institutes for Desert Research, Mitrani Department of Desert Ecology, Ben-Gurion University of the Negev, Midreshet Ben-Gurion, 8499000, Israel
- Institute of Bioscience, Aarhus University, Ny Munkegade 114, 8000, Aarhus, Denmark
| | - Christina Holm
- Institute of Bioscience, Aarhus University, Ny Munkegade 114, 8000, Aarhus, Denmark
| | - Yael Lubin
- Blaustein Institutes for Desert Research, Mitrani Department of Desert Ecology, Ben-Gurion University of the Negev, Midreshet Ben-Gurion, 8499000, Israel.
| | - Trine Bilde
- Institute of Bioscience, Aarhus University, Ny Munkegade 114, 8000, Aarhus, Denmark
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Haney BR, Fewell JH. Ecological drivers and reproductive consequences of non-kin cooperation by ant queens. Oecologia 2018; 187:643-655. [PMID: 29691647 DOI: 10.1007/s00442-018-4148-9] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2018] [Accepted: 04/17/2018] [Indexed: 11/25/2022]
Abstract
The fitness consequences of joining a group are highly dependent on ecological context, especially for non-kin. To assess the relationships between cooperation and environment, we examined variation in colony reproductive success for a harvester ant species that nests either solitarily or with multiple, unrelated queens, a social strategy known as primary polygyny. We measured the reproductive investment of colonies of solitary versus social nesting types at two sites, one with primarily single-queen colonies, and the other with a majority of polygynous nests. Our results were consistent with the hypothesis that cooperative nesting by unrelated ant queens is likely a selection response to difficult environments, rather than a strategy to maximize reproduction under favorable conditions. Fewer colonies at the primarily polygynous site reproduced than at the site with primarily single queen nests, and those that did had lower reproductive investment, as measured by number and total mass of reproductives. Assessment of ecological conditions also support the harsh environment hypothesis. Colony density in the multi-queen population was higher, and nearest neighbor distances were lower for non-reproducing than reproducing colonies. To more directly test the hypothesis that colony reproduction was ecologically constrained, we experimentally supplemented food resources for a subset of colonies at the primary polygyny site. Supplemented colonies increased reproductive investment levels to equal that of colonies at the single-queen population, further indicating that environmental pressures are severe where primary polygyny is dominant, and may drive the evolution of non-kin cooperation in this context.
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Keiser CN, Pinter-Wollman N, Ziemba MJ, Kothamasu KS, Pruitt JN. The primary case is not enough: Variation among individuals, groups and social networks modify bacterial transmission dynamics. J Anim Ecol 2018; 87:369-378. [PMID: 28692130 PMCID: PMC5871623 DOI: 10.1111/1365-2656.12729] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2016] [Accepted: 06/13/2017] [Indexed: 12/26/2022]
Abstract
The traits of the primary case of an infectious disease outbreak, and the circumstances for their aetiology, potentially influence the trajectory of transmission dynamics. However, these dynamics likely also depend on the traits of the individuals with whom the primary case interacts. We used the social spider Stegodyphus dumicola to test how the traits of the primary case, group phenotypic composition and group size interact to facilitate the transmission of a GFP-labelled cuticular bacterium. We also compared bacterial transmission across experimentally generated "daisy-chain" vs. "star" networks of social interactions. Finally, we compared social network structure across groups of different sizes. Groups of 10 spiders experienced more bacterial transmission events compared to groups of 30 spiders, regardless of groups' behavioural composition. Groups containing only one bold spider experienced the lowest levels of bacterial transmission regardless of group size. We found no evidence for the traits of the primary case influencing any transmission dynamics. In a second experiment, bacteria were transmitted to more individuals in experimentally induced star networks than in daisy-chains, on which transmission never exceeded three steps. In both experimental network types, transmission success depended jointly on the behavioural traits of the interacting individuals; however, the behavioural traits of the primary case were only important for transmission on star networks. Larger social groups exhibited lower interaction density (i.e. had a low ratio of observed to possible connections) and were more modular, i.e. they had more connections between nodes within a subgroup and fewer connections across subgroups. Thus, larger groups may restrict transmission by forming fewer interactions and by isolating subgroups that interacted with the primary case. These findings suggest that accounting for the traits of single exposed hosts has less power in predicting transmission dynamics compared to the larger scale factors of the social groups in which they reside. Factors like group size and phenotypic composition appear to alter social interaction patterns, which leads to differential transmission of microbes.
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Affiliation(s)
- Carl N. Keiser
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA, USA
- Biosciences Department, Rice University, Academy of Fellows, Rice University, Houston, TX, USA
| | - Noa Pinter-Wollman
- Department of Ecology and Evolutionary Biology, University of California, Los Angeles, CA, USA
| | - Michael J. Ziemba
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA, USA
| | - Krishna S. Kothamasu
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA, USA
| | - Jonathan N. Pruitt
- Department of Ecology, Evolution, and Marine Biology, University of California, Santa Barbara, CA, USA
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Parthasarathy B, Somanathan H. Body condition and food shapes group dispersal but not solitary dispersal in a social spider. Behav Ecol 2018. [DOI: 10.1093/beheco/ary013] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
- Bharat Parthasarathy
- IISER-TVM Centre for Research and Education in Ecology and Evolution (ICREEE), School of Biology, Indian Institute of Science Education and Research, Thiruvananthapuram, Kerala, India
| | - Hema Somanathan
- IISER-TVM Centre for Research and Education in Ecology and Evolution (ICREEE), School of Biology, Indian Institute of Science Education and Research, Thiruvananthapuram, Kerala, India
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Keiser CN, Howell KA, Pinter-Wollman N, Pruitt JN. Personality composition alters the transmission of cuticular bacteria in social groups. Biol Lett 2017; 12:rsbl.2016.0297. [PMID: 27381885 DOI: 10.1098/rsbl.2016.0297] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2016] [Accepted: 06/15/2016] [Indexed: 12/28/2022] Open
Abstract
The initial stages of a disease outbreak can determine the magnitude of the ensuing epidemic. Though rarely tested in unison, two factors with important consequences for the transmission dynamics of infectious agents are the collective traits of the susceptible population and the individual traits of the index case (i.e. 'patient zero'). Here, we test whether the personality composition of a social group can explain horizontal transmission dynamics of cuticular bacteria using the social spider Stegodyphus dumicola We exposed focal spiders of known behavioural phenotypes with a GFP-transformed cuticular bacterium (Pantoea sp.) and placed them in groups of 10 susceptible individuals (i.e. those with no experience with this bacterium). We measured bacterial transmission to groups composed of either all shy spiders, 10% bold spiders or 40% bold spiders. We found that colonies with 40% bold spiders experienced over twice the incidence of transmission compared to colonies with just 10% bold individuals after only 24 h of interaction. Colonies of all shy spiders experienced an intermediate degree of transmission. Interestingly, we did not detect an effect of the traits of the index case on transmission. These data suggest that the phenotypic composition of the susceptible population can have a greater influence on the degree of early transmission events than the traits of the index case.
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Affiliation(s)
- Carl N Keiser
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA 15260, USA
| | - Kimberly A Howell
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA 15260, USA
| | - Noa Pinter-Wollman
- BioCircuits Institute, University of California, San Diego, La Jolla, CA 92093, USA
| | - Jonathan N Pruitt
- Department of Ecology, Evolution, and Marine Biology, University of California, Santa Barbara, CA 93106, USA
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36
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Sitkov-Sharon G, Tremmel M, Bouskila A, Lubin Y, Harari AR. Inbreeding, but not seed availability, affects dispersal and reproductive success in a seed-inhabiting social beetle. Behav Ecol Sociobiol 2017. [DOI: 10.1007/s00265-017-2407-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Lichtenstein JL, Wright CM, Luscuskie LP, Montgomery GA, Pinter-Wollman N, Pruitt JN. Participation in cooperative prey capture and the benefits gained from it are associated with individual personality. Curr Zool 2017; 63:561-567. [PMID: 29033979 PMCID: PMC5637736 DOI: 10.1093/cz/zow097] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2016] [Accepted: 09/20/2016] [Indexed: 11/13/2022] Open
Abstract
In animal societies, behavioral idiosyncrasies of the individuals often guide which tasks they should perform. Such personality-specific task participation can increase individual task efficiency, thereby improving group performance. While several recent studies have documented group-level benefits of within-group behavioral (i.e., personality) diversity, how these benefits are realized at the individual level is unclear. Here we probe the individual-level benefits of personality-driven task participation in the social spider Stegodyphus dumicola. In S. dumicola, the presence of at least one highly bold individual catalyzes foraging behavior in shy colony members, and all group constituents heavily compete for prey. We assessed boldness by examining how quickly spiders resumed normal movement after a simulated predator attack. We test here whether (1) participants in collective foraging gain more mass from prey items and (2) whether bold individuals are less resistant to starvation than shy spiders, which would motivate the bold individuals to forage more. Next, we assembled colonies of shy spiders with and without a bold individual, added one prey item, and then tracked the mass gain of each individual spider after this single feeding event. We found that spiders that participated in prey capture (whether bold or shy) gained more mass than nonparticipators, and colonies containing a single bold spider gained more total mass than purely shy colonies. We also found that bold spiders participated in more collective foraging events and were more susceptible to starvation than shy spiders, suggesting that the aggressive foraging of bold individuals may represent a strategy to offset starvation risk. These findings add to the body of evidence that animal personality can shape social organization, individual performance, and group success.
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Affiliation(s)
| | - Colin M. Wright
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA 15260, USA
| | - Lauren P. Luscuskie
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA 15260, USA
| | - Graham A. Montgomery
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA 15260, USA
| | - Noa Pinter-Wollman
- Department of Ecology and Evolutionary Biology, University of California Los Angeles, CA 90095, USAand
| | - Jonathan N. Pruitt
- Department of Ecology, Evolution, and Marine Biology, University of California Santa Barbara, Santa Barbara, CA 93106, USA
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Junghanns A, Holm C, Schou MF, Sørensen AB, Uhl G, Bilde T. Extreme allomaternal care and unequal task participation by unmated females in a cooperatively breeding spider. Anim Behav 2017. [DOI: 10.1016/j.anbehav.2017.08.006] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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Walter A, Bechsgaard J, Scavenius C, Dyrlund TS, Sanggaard KW, Enghild JJ, Bilde T. Characterisation of protein families in spider digestive fluids and their role in extra-oral digestion. BMC Genomics 2017; 18:600. [PMID: 28797246 PMCID: PMC5553785 DOI: 10.1186/s12864-017-3987-9] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2017] [Accepted: 08/01/2017] [Indexed: 12/19/2022] Open
Abstract
BACKGROUND Spiders are predaceous arthropods that are capable of subduing and consuming relatively large prey items compared to their own body size. For this purpose, spiders have evolved potent venoms to immobilise prey and digestive fluids that break down nutrients inside the prey's body by means of extra-oral digestion (EOD). Both secretions contain an array of active proteins, and an overlap of some components has been anecdotally reported, but not quantified. We systematically investigated the extent of such protein overlap. As venom injection and EOD succeed each other, we further infer functional explanations, and, by comparing two spider species belonging to different clades, assess its adaptive significance for spider EOD in general. RESULTS We describe the protein composition of the digestive fluids of the mygalomorph Acanthoscurria geniculata and the araneomorph Stegodyphus mimosarum, in comparison with previously published data on a third spider species. We found a number of similar hydrolases being highly abundant in all three species. Among them, members of the family of astacin-like metalloproteases were particularly abundant. While the importance of these proteases in spider venom and digestive fluid was previously noted, we now highlight their widespread use across different spider taxa. Finally, we found species specific differences in the protein overlap between venom and digestive fluid, with the difference being significantly greater in S. mimosarum compared to A. geniculata. CONCLUSIONS The injection of venom precedes the injection with digestive fluid, and the overlap of proteins between venom and digestive fluid suggests an early involvement in EOD. Species specific differences in the overlap may reflect differences in ecology between our two study species. The protein composition of the digestive fluid of all the three species we compared is highly similar, suggesting that the cocktail of enzymes is highly conserved and adapted to spider EOD.
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Affiliation(s)
- André Walter
- Department of Bioscience, Aarhus University, Aarhus, Denmark.
| | | | - Carsten Scavenius
- Department of Molecular Biology and Genetics, Aarhus University, Aarhus, Denmark
| | - Thomas S Dyrlund
- Department of Molecular Biology and Genetics, Aarhus University, Aarhus, Denmark
| | - Kristian W Sanggaard
- Department of Molecular Biology and Genetics, Aarhus University, Aarhus, Denmark
| | - Jan J Enghild
- Department of Molecular Biology and Genetics, Aarhus University, Aarhus, Denmark
| | - Trine Bilde
- Department of Bioscience, Aarhus University, Aarhus, Denmark
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Settepani V, Schou MF, Greve M, Grinsted L, Bechsgaard J, Bilde T. Evolution of sociality in spiders leads to depleted genomic diversity at both population and species levels. Mol Ecol 2017; 26:4197-4210. [DOI: 10.1111/mec.14196] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2016] [Revised: 04/06/2017] [Accepted: 04/10/2017] [Indexed: 12/21/2022]
Affiliation(s)
- V. Settepani
- Department of Bioscience; Aarhus University; Aarhus C Denmark
| | - M. F. Schou
- Department of Bioscience; Aarhus University; Aarhus C Denmark
| | - M. Greve
- Department of Plant Science; University of Pretoria; Hatfield South Africa
| | - L. Grinsted
- School of Biological Sciences; Royal Holloway University of London; Egham UK
| | - J. Bechsgaard
- Department of Bioscience; Aarhus University; Aarhus C Denmark
| | - T. Bilde
- Department of Bioscience; Aarhus University; Aarhus C Denmark
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41
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Pinter-Wollman N, Mi B, Pruitt JN. Replacing bold individuals has a smaller impact on group performance than replacing shy individuals. Behav Ecol 2017. [DOI: 10.1093/beheco/arx054] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
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42
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Hoffman CR, Avilés L. Rain, predators, and spider sociality: a manipulative experiment. Behav Ecol 2017. [DOI: 10.1093/beheco/arx010] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Affiliation(s)
- Catherine R. Hoffman
- Department of Zoology, University of British Columbia, 6270 University Blvd., Vancouver, BC V6T 1Z4, Canada
| | - Leticia Avilés
- Department of Zoology, University of British Columbia, 6270 University Blvd., Vancouver, BC V6T 1Z4, Canada
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Monks JM, O'Donnell CFJ. Social implications of a colony collapse in a highly structured vertebrate species (long-tailed bat, Chalinolobus tuberculatus
). Anim Conserv 2016. [DOI: 10.1111/acv.12324] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- J. M. Monks
- Science and Policy Group; Department of Conservation; P O Box 5244 Dunedin New Zealand
| | - C. F. J. O'Donnell
- Science and Policy Group; Department of Conservation; Private Bag 4715; Christchurch Mail Centre; Christchurch New Zealand
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Yang WJ, Maldonado-Chaparro AA, Blumstein DT. A cost of being amicable in a hibernating mammal. Behav Ecol 2016. [DOI: 10.1093/beheco/arw125] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Pinter-Wollman N, Keiser CN, Wollman R, Pruitt JN. The Effect of Keystone Individuals on Collective Outcomes Can Be Mediated through Interactions or Behavioral Persistence. Am Nat 2016; 188:240-52. [PMID: 27420788 PMCID: PMC5475371 DOI: 10.1086/687235] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Collective behavior emerges from interactions among group members who often vary in their behavior. The presence of just one or a few keystone individuals, such as leaders or tutors, may have a large effect on collective outcomes. These individuals can catalyze behavioral changes in other group members, thus altering group composition and collective behavior. The influence of keystone individuals on group function may lead to trade-offs between ecological situations, because the behavioral composition they facilitate may be suitable in one situation but not another. We use computer simulations to examine various mechanisms that allow keystone individuals to exert their influence on group members. We further discuss a trade-off between two potentially conflicting collective outcomes, cooperative prey attack and disease dynamics. Our simulations match empirical data from a social spider system and produce testable predictions for the causes and consequences of the influence of keystone individuals on group composition and collective outcomes. We find that a group's behavioral composition can be impacted by the keystone individual through changes to interaction patterns or behavioral persistence over time. Group behavioral composition and the mechanisms that drive the distribution of phenotypes influence collective outcomes and lead to trade-offs between disease dynamics and cooperative prey attack.
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Affiliation(s)
- Noa Pinter-Wollman
- BioCircuits Institute, University of California, San Diego, La Jolla, California 92093
- San Diego Center for Systems Biology, University of California, San Diego, La Jolla, California 92093
| | - Carl N. Keiser
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania 15260
| | - Roy Wollman
- San Diego Center for Systems Biology, University of California, San Diego, La Jolla, California 92093
- Department of Chemistry and Biochemistry and Section for Cellular and Developmental Biology, University of California, San Diego, La Jolla, California 92093
| | - Jonathan N. Pruitt
- Department of Ecology, Evolution, and Marine Biology, University of California, Santa Barbara, California 93106
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47
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Sharpe RV, Avilés L. Prey size and scramble vs. contest competition in a social spider: implications for population dynamics. J Anim Ecol 2016; 85:1401-10. [PMID: 27300160 DOI: 10.1111/1365-2656.12559] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2015] [Accepted: 06/07/2016] [Indexed: 11/27/2022]
Abstract
There are many benefits of group living, but also substantial costs, one of which is competition for resources. How scarce food resources are distributed among different members of a population or social group - whether via scramble or contest competition - can influence not only the variance in individual fitness, but also the stability and therefore survival of the group or population. Attributes of the food resources themselves, such as their size, may influence the type of intraspecific competition that occurs and therefore the intrinsic stability of a group or population. By experimentally manipulating the size of prey fed to artificial colonies of the social spider Anelosimus eximius, we investigated whether prey size could alter the degree of scramble vs. contest competition that takes place and, thus, potentially influence colony population dynamics. We found that large prey were shared more evenly than small prey and that individuals in poor condition were more likely to feed when prey were large than when prey were small. Additionally, we show that individuals participating in prey capture are also more likely to feed on the captured prey. We developed a simple mathematical model to explore the prey sizes that would be energetically worth defending, i.e. prey that are 'economically defendable'. The model shows that neither very small prey, nor prey above a certain size is worth monopolizing, with only intermediate size prey being 'economically defendable'. We therefore suggest the small and large prey in our experiment corresponds to our model's intermediate and large prey categories, respectively. As the size of prey captured by social spider colonies increases with colony size, our findings suggest that scramble competition may predominate in large colonies. Scramble competition, combined with the fact that prey biomass per capita declines as colonies grow beyond a certain size, would then explain why extremely large colonies of this social spider may suddenly go extinct. Our project thus illustrates the potential triple link between characteristics of the resources, individual behaviour and population dynamics, a link rarely considered in an empirical setting.
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Affiliation(s)
- Ruth V Sharpe
- Department of Zoology, University of British Columbia, Vancouver, BC, Canada
| | - Leticia Avilés
- Department of Zoology, University of British Columbia, Vancouver, BC, Canada
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48
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Keiser CN, Pinter-Wollman N, Augustine DA, Ziemba MJ, Hao L, Lawrence JG, Pruitt JN. Individual differences in boldness influence patterns of social interactions and the transmission of cuticular bacteria among group-mates. Proc Biol Sci 2016; 283:20160457. [PMID: 27097926 PMCID: PMC4855390 DOI: 10.1098/rspb.2016.0457] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2016] [Accepted: 03/30/2016] [Indexed: 12/15/2022] Open
Abstract
Despite the importance of host attributes for the likelihood of associated microbial transmission, individual variation is seldom considered in studies of wildlife disease. Here, we test the influence of host phenotypes on social network structure and the likelihood of cuticular bacterial transmission from exposed individuals to susceptible group-mates using female social spiders (Stegodyphus dumicola). Based on the interactions of resting individuals of known behavioural types, we assessed whether individuals assorted according to their behavioural traits. We found that individuals preferentially interacted with individuals of unlike behavioural phenotypes. We next applied a green fluorescent protein-transformed cuticular bacterium,Pantoeasp., to individuals and allowed them to interact with an unexposed colony-mate for 24 h. We found evidence for transmission of bacteria in 55% of cases. The likelihood of transmission was influenced jointly by the behavioural phenotypes of both the exposed and susceptible individuals: transmission was more likely when exposed spiders exhibited higher 'boldness' relative to their colony-mate, and when unexposed individuals were in better body condition. Indirect transmission via shared silk took place in only 15% of cases. Thus, bodily contact appears key to transmission in this system. These data represent a fundamental step towards understanding how individual traits influence larger-scale social and epidemiological dynamics.
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Affiliation(s)
- Carl N Keiser
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA 15260, USA
| | - Noa Pinter-Wollman
- BioCircuits Institute, University of California, San Diego, La Jolla, CA 92093, USA
| | - David A Augustine
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA 15260, USA
| | - Michael J Ziemba
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA 15260, USA
| | - Lingran Hao
- BioCircuits Institute, University of California, San Diego, La Jolla, CA 92093, USA
| | - Jeffrey G Lawrence
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA 15260, USA
| | - Jonathan N Pruitt
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA 15260, USA Department of Ecology, Evolution, and Marine Biology, University of California, Santa Barbara, CA 93106, USA
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49
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Berger-Tal R, Berner-Aharon N, Aharon S, Tuni C, Lubin Y. Good reasons to leave home: proximate dispersal cues in a social spider. J Anim Ecol 2016; 85:1035-42. [PMID: 27084588 DOI: 10.1111/1365-2656.12534] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2015] [Accepted: 03/29/2016] [Indexed: 11/30/2022]
Abstract
Natal dispersal is a successful tactic under a range of conditions in spite of significant costs. Habitat quality is a frequent proximate cause of dispersal, and studies have shown that dispersal increases both when natal habitat quality is good or poor. In social species kin competition, favouring dispersal may be balanced by the benefits of group living, favouring philopatry. We investigated the effect of changes in the local environment on natal dispersal of adult females in a social spider species, Stegodyphus dumicola (Araneae, Eresidae), with a flexible breeding system, where females can breed either within the colony or individually following dispersal. We manipulated foraging opportunities in colonies by either removing the capture webs or by adding prey and recorded the number of dispersing females around each focal colony, and their survival and reproductive success. We predicted that increasing kin competition should increase dispersal of less-competitive individuals, while reducing competition could cause either less dispersal (less competition) or more dispersal (a cue indicating better chances to establish a new colony). Dispersal occurred earlier and at a higher rate in both food-augmented and web-removal colonies than in control colonies. Fewer dispersing females survived and reproduced in the web-removal group than in the control or food-augmented groups. The results support our prediction that worsening conditions in web-removal colonies favour dispersal, whereby increased kin competition and increased energy expenditure on web renewal cause females to leave the natal colony. By contrast, prey augmentation may serve as a habitat-quality cue; when the surrounding habitat is expected to be of high quality, females assess the potential benefit of establishing a new colony to be greater than the costs of dispersal.
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Affiliation(s)
- Reut Berger-Tal
- Mitrani Department of Desert Ecology, Blaustein Institutes for Desert Research, Ben-Gurion University, Midreshet Ben-Gurion, 8499000, Israel.,Department of Bioscience, Aarhus University, Ny Munkegade 116, building 1540, 8000, Aarhus C, Denmark
| | - Na'ama Berner-Aharon
- Mitrani Department of Desert Ecology, Blaustein Institutes for Desert Research, Ben-Gurion University, Midreshet Ben-Gurion, 8499000, Israel
| | - Shlomi Aharon
- Mitrani Department of Desert Ecology, Blaustein Institutes for Desert Research, Ben-Gurion University, Midreshet Ben-Gurion, 8499000, Israel
| | - Cristina Tuni
- Department of Bioscience, Aarhus University, Ny Munkegade 116, building 1540, 8000, Aarhus C, Denmark.,Department Biology II, Ludwig Maximilians University Munich, Großhaderner Str. 2, 82152, Planegg-Martinsried, Germany
| | - Yael Lubin
- Mitrani Department of Desert Ecology, Blaustein Institutes for Desert Research, Ben-Gurion University, Midreshet Ben-Gurion, 8499000, Israel
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50
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Keiser CN, Wright CM, Pruitt JN. Increased bacterial load can reduce or negate the effects of keystone individuals on group collective behaviour. Anim Behav 2016. [DOI: 10.1016/j.anbehav.2016.02.010] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
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