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York J. Costly conspicuousness reveals benefits of sexual dimorphism in brood parasitic diederik cuckoos. Ecol Evol 2024; 14:e11263. [PMID: 38779529 PMCID: PMC11108799 DOI: 10.1002/ece3.11263] [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: 07/14/2023] [Revised: 03/18/2024] [Accepted: 03/27/2024] [Indexed: 05/25/2024] Open
Abstract
The existence of adult sexual dimorphism is typically explained as a consequence of sexual selection, yet coevolutionary drivers of sexual dimorphism frequently remain untested. Here, I investigate the role of sexual dimorphism in host-parasite interactions of the brood parasitic diederik cuckoo, Chrysococcyx caprius. Female diederik cuckoos are more cryptic in appearance and pose a threat to the clutch, while male diederik cuckoos are conspicuous and not a direct threat. Specifically, I examine whether sexual dimorphism in diederik cuckoos provokes threat-level sensitive responses in Southern red bishop, Euplectes orix, hosts. I use experimentally simulated nest intrusions to test whether hosts have the capacity to differentially (i) detect, and/or (ii) discriminate between, male and female diederik cuckoos, relative to harmless controls. Overall, I found no evidence that diederik cuckoos differ in detectability, since both sexes are comparable to controls in the probability and speed of host detection. Furthermore, neither male nor female hosts discriminate between sexually dimorphic diederik cuckoos when engaging in frontline nest defences. However, hosts that witnessed a male diederik cuckoo during the trial were more likely to reject odd eggs. Moreover, experimental eggs were significantly more likely to be rejected when female bishops observed a male compared to a female diederik cuckoo. While the cryptic appearance of female diederik cuckoos does not reduce detection by hosts, it does provide the benefit of anonymity given the egg rejection costs of conspicuous male-like appearance in the nest vicinity. These findings have implications for the evolution and maintenance of sexual dimorphism across the Cuculidae, and highlight the value of testing assumptions about the ecological drivers of sexual dimorphism.
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Affiliation(s)
- Jennifer York
- Department of ZoologyUniversity of CambridgeCambridgeUK
- Department of Zoology and EntomologyUniversity of PretoriaHatfield, PretoriaSouth Africa
- Department of Ecology and Evolutionary BiologyPrinceton UniversityPrincetonNew JerseyUSA
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Montgomery TM, Lehmann KDS, Gregg S, Keyser K, McTigue LE, Beehner JC, Holekamp KE. Determinants of hyena participation in risky collective action. Proc Biol Sci 2023; 290:20231390. [PMID: 38018101 PMCID: PMC10685128 DOI: 10.1098/rspb.2023.1390] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2023] [Accepted: 11/03/2023] [Indexed: 11/30/2023] Open
Abstract
Collective action problems arise when cooperating individuals suffer costs of cooperation, while the benefits of cooperation are received by both cooperators and defectors. We address this problem using data from spotted hyenas fighting with lions. Lions are much larger and kill many hyenas, so these fights require cooperative mobbing by hyenas for them to succeed. We identify factors that predict when hyena groups engage in cooperative fights with lions, which individuals choose to participate and how the benefits of victory are distributed among cooperators and non-cooperators. We find that cooperative mobbing is better predicted by lower costs (no male lions, more hyenas) than higher benefits (need for food). Individual participation is facilitated by social factors, both over the long term (close kin, social bond strength) and the short term (greeting interactions prior to cooperation). Finally, we find some direct benefits of participation: after cooperation, participants were more likely to feed at contested carcasses than non-participants. Overall, these results are consistent with the hypothesis that, when animals face dangerous cooperative dilemmas, selection favours flexible strategies that are sensitive to dynamic factors emerging over multiple time scales.
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Affiliation(s)
- Tracy M. Montgomery
- Department of Integrative Biology and Program in Ecology, Evolution, and behavior, Michigan State University, 288 Farm Lane, East Lansing, MI 48824, USA
- Mara Hyena Project, PO Box 164-00502, Karen, Nairobi, Kenya
- Department for the Ecology of Animal Societies, Max Planck Institute for Animal Behavior, Bücklestraße 5a, 78467 Konstanz, Germany
- Center for the Advanced Study of Collective Behavior, University of Konstanz, Universitätsstraße 10, 78464 Konstanz, Germany
| | - Kenna D. S. Lehmann
- Department of Integrative Biology and Program in Ecology, Evolution, and behavior, Michigan State University, 288 Farm Lane, East Lansing, MI 48824, USA
- Human Biology Program, Michigan State University, 288 Farm Lane, East Lansing, MI 48824, USA
- Mara Hyena Project, PO Box 164-00502, Karen, Nairobi, Kenya
| | - Samantha Gregg
- Department of Integrative Biology and Program in Ecology, Evolution, and behavior, Michigan State University, 288 Farm Lane, East Lansing, MI 48824, USA
| | - Kathleen Keyser
- Department of Integrative Biology and Program in Ecology, Evolution, and behavior, Michigan State University, 288 Farm Lane, East Lansing, MI 48824, USA
| | - Leah E. McTigue
- Department of Integrative Biology and Program in Ecology, Evolution, and behavior, Michigan State University, 288 Farm Lane, East Lansing, MI 48824, USA
- Rocky Mountain Research Station, Colorado State University, 240 W Prospect St, Fort Collins, CO 80525, USA
| | - Jacinta C. Beehner
- Department of Psychology, University of Michigan, 530 Church Street, Ann Arbor, MI 48109, USA
- Department of Anthropology, University of Michigan, 1085 South University Avenue, Ann Arbor, MI 48109, USA
| | - Kay E. Holekamp
- Department of Integrative Biology and Program in Ecology, Evolution, and behavior, Michigan State University, 288 Farm Lane, East Lansing, MI 48824, USA
- Mara Hyena Project, PO Box 164-00502, Karen, Nairobi, Kenya
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McGuire KM, Sauther ML. Characterizing group and individual engagement in intergroup encounters between small groups of ring-tailed lemurs (Lemur catta) on St. Catherines Island, USA. Primates 2023; 64:161-176. [PMID: 36418748 DOI: 10.1007/s10329-022-01036-7] [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: 06/30/2022] [Accepted: 11/02/2022] [Indexed: 11/25/2022]
Abstract
Primate species exhibit considerable variation in behavior and outcomes during intergroup encounters (IGEs). Social group characteristics, like group size, and individual traits, such as sex, rank, and reproductive status, within those groups can influence both IGE engagement and outcomes. To better understand the impact of group heterogeneity on IGEs, we must examine individual strategies to elucidate individual costs and benefits of engaging in these interactions. Here, we present a descriptive study of the IGEs between two small social groups of ring-tailed lemurs (Lemur catta) on St. Catherines Island, GA, USA. We distinguish between dyadic and multiple-individual interactions between groups to compare collective and individual agonistic engagement. All encounters occurred when the East Road group (N = 7 individuals) traveled from the center of their home range to the boundary with Windmill group's (N = 5 individuals) home range, indicating that East Road might have been actively testing this boundary for access to food resources, sleeping trees, and mating opportunities. We also found notable individual variation in participation during IGEs. The daughters of the highest-ranking females were the most-engaged in dyadic intergroup and intragroup aggression, had high "win" rates during intergroup dyadic encounters, and engaged in intergroup multiple-individual interactions at high levels. These findings indicate that they might value their home range more as "potential alphas" compared to other group members. Dominant females were the most engaged in multiple-individual interactions, suggesting that they contribute heavily to collective action that might result in a gain or loss of access to resources. Finally, these two small groups might be equally matched despite the two-individual group size disparity due to individual free-riding strategies. Future research should focus on individual strategies during IGEs to characterize the complex decisions and trade-offs that influence participation.
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Affiliation(s)
- Kathleen M McGuire
- Department of Anthropology, University of Colorado Boulder, Boulder, CO, 80302, USA.
| | - Michelle L Sauther
- Department of Anthropology, University of Colorado Boulder, Boulder, CO, 80302, USA
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Wood EM, Capilla-Lasheras P, Cram DL, Walker LA, York JE, Lange A, Hamilton PB, Tyler CR, Young AJ. Social dominance and rainfall predict telomere dynamics in a cooperative arid-zone bird. Mol Ecol 2022; 31:6141-6154. [PMID: 33657651 DOI: 10.1111/mec.15868] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2020] [Accepted: 02/17/2021] [Indexed: 02/02/2023]
Abstract
In many vertebrate societies dominant individuals breed at substantially higher rates than subordinates, but whether this hastens ageing remains poorly understood. While frequent reproduction may trade off against somatic maintenance, the extraordinary fecundity and longevity of some social insect queens highlight that breeders need not always suffer more rapid somatic deterioration than their nonbreeding subordinates. Here, we used extensive longitudinal assessments of telomere dynamics to investigate the impact of dominance status on within-individual age-related changes in somatic integrity in a wild social bird, the white-browed sparrow-weaver (Plocepasser mahali). Dominant birds, who monopolise reproduction, had neither shorter telomeres nor faster telomere attrition rates over the long-term (1-5 years) than their subordinates. However, over shorter (half-year) time intervals dominants with shorter telomeres showed lower rates of telomere attrition (and evidence suggestive of telomere lengthening), while the same was not true among subordinates. Dominants may therefore invest more heavily in telomere length regulation (and/or somatic maintenance more broadly); a strategy that could mitigate the long-term costs of reproductive effort, leaving their long-term telomere dynamics comparable to those of subordinates. Consistent with the expectation that reproduction entails short-term costs to somatic integrity, telomere attrition rates were most severe for all birds during the breeding seasons of wetter years (rainfall is the key driver of reproductive activity in this arid-zone species). Our findings suggest that, even in vertebrate societies in which dominants monopolise reproduction, dominants may experience long-term somatic integrity trajectories indistinguishable from those of their nonreproductive subordinates.
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Affiliation(s)
- Emma M Wood
- Centre for Ecology & Conservation, University of Exeter, Penryn, UK
| | - Pablo Capilla-Lasheras
- Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, Glasgow, UK
| | - Dominic L Cram
- Department of Zoology, University of Cambridge, Cambridge, UK
| | - Lindsay A Walker
- Geoffrey Pope, Biosciences, College of Life and Environmental Sciences, University of Exeter, Exeter, UK
| | - Jenny E York
- Department of Zoology, University of Cambridge, Cambridge, UK.,Department of Zoology and Entomology, University of Pretoria, Pretoria, South Africa.,Department of Ecology and Evolutionary Biology, Princeton University, Princeton, NJ, USA
| | - Anke Lange
- Geoffrey Pope, Biosciences, College of Life and Environmental Sciences, University of Exeter, Exeter, UK
| | - Patrick B Hamilton
- Geoffrey Pope, Biosciences, College of Life and Environmental Sciences, University of Exeter, Exeter, UK
| | - Charles R Tyler
- Geoffrey Pope, Biosciences, College of Life and Environmental Sciences, University of Exeter, Exeter, UK
| | - Andrew J Young
- Centre for Ecology & Conservation, University of Exeter, Penryn, UK
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Superb fairy-wrens with extreme exploration phenotypes respond more strongly to simulated territory intrusions. Anim Behav 2022. [DOI: 10.1016/j.anbehav.2022.08.015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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Werba JA, Stuckert AM, Edwards M, McCoy MW. Stranger danger: A meta-analysis of the dear enemy hypothesis. Behav Processes 2021; 194:104542. [PMID: 34818561 DOI: 10.1016/j.beproc.2021.104542] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2021] [Revised: 11/10/2021] [Accepted: 11/11/2021] [Indexed: 01/01/2023]
Abstract
The dear enemy hypothesis predicts that territorial individuals will be less aggressive toward known neighbors than to strangers. This hypothesis has been well studied and there is a wealth of data demonstrating its prevalence in some taxa. However, a quantitative synthesis is needed to test the generality of the phenomenon, identify key mechanisms driving the behavior, and guide future research. In this study, we conduct a meta-analysis and, we test the importance of the location of intrusion, the type of experiment conducted (field, laboratory, or neutral arenas), and the sex and breeding status of territory holders, on the occurrence of dear enemy behavior. We also test how various ecological and life history traits, such as territory type, stimulus of intrusion, and taxonomic group, affect the magnitude of dear enemy behavior. We find that this phenomenon is common and that taxonomic class and breeding status are correlated with the expression of dear enemy behaviors. Further, we found that the way authors measure aggression influences the likelihood of identifying dear enemy responses, and thus we discuss potential pitfalls of dear enemy studies. Considering this conclusion, we discuss future lines of inquiry that could more directly examine the mechanisms of the dear enemy phenomenon.
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Affiliation(s)
- Jo A Werba
- Department Ecosystem Sciences and Management, Pennsylvania State University, University Park, PA 16802, USA.
| | - Adam Mm Stuckert
- Department of Molecular and Cellular Biology, University of New Hampshire, Durham, NH 03857, USA
| | - Matthew Edwards
- Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA
| | - Michael W McCoy
- Department of Biology, East Carolina University, Greenville NC 27858, USA
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Capilla-Lasheras P, Harrison X, Wood EM, Wilson AJ, Young AJ. Altruistic bet-hedging and the evolution of cooperation in a Kalahari bird. SCIENCE ADVANCES 2021; 7:eabe8980. [PMID: 34550732 PMCID: PMC8457656 DOI: 10.1126/sciadv.abe8980] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
Altruism is globally associated with unpredictable environments, but we do not understand why. New theory has highlighted that unpredictable environments could favor the evolution of altruism if altruistic acts reduce environmentally induced variance in the reproductive success of relatives (“altruistic bet-hedging”). Here, we show that altruism does indeed reduce environmentally induced reproductive variance in a wild cooperative bird. Our decade-long field study reveals that altruistic helping actually has no overall effect on the mean reproductive success of relatives but instead reduces their reproductive variance. This remarkable pattern arises because helpers improve reproductive performance in dry conditions but reduce it in wet conditions. Helpers thereby specifically reduce rainfall-induced reproductive variance, the very mechanism required for altruistic bet-hedging to explain the enigmatic global association between avian altruism and unpredictable rainfall.
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