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Strugariu A, Martin RA. Factor in Fear: Interference Competition in Polymorphic Spadefoot Toad Tadpoles and Its Potential Role in Disruptive Selection. Animals (Basel) 2023; 13:ani13071264. [PMID: 37048520 PMCID: PMC10093105 DOI: 10.3390/ani13071264] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2023] [Revised: 04/02/2023] [Accepted: 04/03/2023] [Indexed: 04/09/2023] Open
Abstract
Disruptive selection arises when extreme phenotypes have a fitness advantage compared to more-intermediate phenotypes. Theory and evidence suggest that intraspecific resource competition is a key driver of disruptive selection. However, while competition can be indirect (exploitative) or direct (interference), the role of interference competition in disruptive selection has not been tested, and most models of disruptive selection assume exploitative competition. We experimentally investigated whether the type of competition affects the outcome of competitive interactions using a system where disruptive selection is common: Mexican spadefoot toads (Spea multiplicata). Spea tadpoles develop into alternative resource-use phenotypes: carnivores, which consume fairy shrimp and other tadpoles, and omnivores, which feed on algae and detritus. Tadpoles intermediate in phenotype have low fitness when competition is intense, as they are outcompeted by the specialized tadpoles. Our experiments revealed that the presence of carnivores significantly decreased foraging behavior in intermediate tadpoles, and that intermediate tadpoles had significantly lower growth rates in interference competition treatments with carnivores but not with omnivores. Interference competition may therefore be important in driving disruptive selection. As carnivore tadpoles are also cannibalistic, the ‘fear’ effect may have a greater impact on intermediate tadpoles than exploitative competition alone, similarly to non-consumptive effects in predator–prey or intraguild relationships.
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Affiliation(s)
- Alexandru Strugariu
- Department of Exact and Natural Sciences, Institute of Interdisciplinary Research, Alexandru Ioan Cuza University of Iași, 700057 Iași, Romania
| | - Ryan Andrew Martin
- Department of Biology, Case Western Reserve University, Cleveland, OH 44106, USA
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2
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Hammond A, Rowland T, Mills DS, Pilot M. Comparison of behavioural tendencies between “dangerous dogs” and other domestic dog breeds – Evolutionary context and practical implications. Evol Appl 2022; 15:1806-1819. [DOI: 10.1111/eva.13479] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2022] [Revised: 08/18/2022] [Accepted: 08/21/2022] [Indexed: 12/20/2022] Open
Affiliation(s)
- Alexa Hammond
- School of Life Sciences University of Lincoln Lincoln UK
| | - Thomas Rowland
- School of Life Sciences University of Lincoln Lincoln UK
| | | | - Małgorzata Pilot
- School of Life Sciences University of Lincoln Lincoln UK
- Museum and Institute of Zoology Polish Academy of Sciences Gdańsk Poland
- Faculty of Biology University of Gdańsk Gdańsk Poland
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3
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Bai J, Freeberg TM, Lucas JR, Sieving KE. A community context for aggression? Multi-species audience effects on territorial aggression in two species of Paridae. Ecol Evol 2021; 11:5305-5319. [PMID: 34026008 PMCID: PMC8131767 DOI: 10.1002/ece3.7421] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Revised: 02/14/2021] [Accepted: 02/25/2021] [Indexed: 11/29/2022] Open
Abstract
Territorial aggression in birds is widely observed and is commonly linked to sex, age, body size, physiology, seasonal cues, food resource, urbanization, and a variety of social contexts including conspecific audience effects. However, little is known about the heterospecific audience effects on territorial aggression.Here, we address an emerging idea that heterospecific audience effects may be pervasive influences in the social lives of free-living birds. We tested the hypothesis that the composition, number, and relative body size of heterospecific audiences observing an aggressive contest will influence the response probability and intensity of aggression displayed.We subjected two Paridae species, tufted titmouse (TUTI, Baeolophus bicolor) and Carolina chickadee (CACH, Poecile carolinensis), to playbacks of aggressive calls during a breeding season in north-central Florida. At widely spaced playback sites (N = 134) in woodland habitats, we characterized the makeup of heterospecific audiences, aggression type (intra vs. interspecific territoriality), local population density, and various environmental factors (tree density, wind speed, and noise level) that are likely to influence territorial aggression.We found that the presence of heterospecific audiences increased TUTI aggression levels and that both parids were more likely to respond to playback stimuli when their audiences had higher heterospecific diversity (more heterospecific individuals and species). We also found TUTI were more likely to respond when CACH were present but not vice versa.In conclusion, we found evidence that heterospecific audiences significantly influenced the metrics of territorial aggression of free-living animals and we suggest that the definition of audience effects on the behavior of free-living animals be expanded to incorporate heterospecific audiences.
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Affiliation(s)
- Jin Bai
- Department of Wildlife Ecology and ConservationUniversity of FloridaGainesvilleFLUSA
| | - Todd M. Freeberg
- Department of PsychologyUniversity of Tennessee – KnoxvilleKnoxvilleTNUSA
| | - Jeffrey R. Lucas
- Department of Biological SciencesPurdue UniversityWest LafayetteINUSA
| | - Kathryn E. Sieving
- Department of Wildlife Ecology and ConservationUniversity of FloridaGainesvilleFLUSA
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4
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Kleptoparasitic interactions modeling varying owner and intruder hunger awareness. Theor Popul Biol 2020; 136:31-40. [DOI: 10.1016/j.tpb.2020.11.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2020] [Revised: 10/13/2020] [Accepted: 11/06/2020] [Indexed: 11/21/2022]
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5
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Rusch TW, Sears MW, Angilletta MJ. Lizards perceived abiotic and biotic stressors independently when competing for shade in terrestrial mesocosms. Horm Behav 2018; 106:44-51. [PMID: 30218647 DOI: 10.1016/j.yhbeh.2018.09.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/26/2018] [Revised: 09/03/2018] [Accepted: 09/10/2018] [Indexed: 11/21/2022]
Abstract
Hormones such as glucocorticoids and androgens enable animals to respond adaptively to environmental stressors. For this reason, circulating glucocorticoids became a popular biomarker for estimating the quality of an environment, and circulating androgens are frequently used to indicate social dominance. Here, we show that access to thermal resources influence the hormones and behavior of male lizards (Sceloporus jarrovi). We exposed isolated and paired males to different thermal landscapes, ranging from one large patch of shade to sixteen smaller patches. Both the presence of a competitor and the patchiness of the thermal environment influenced hormone concentrations and movement patterns. When shade was concentrated in space, paired lizards competed more aggressively and circulated more corticosterone. Even without competitors, lizards circulated more corticosterone in landscapes with fewer patches of shade. Conversely, shifts in circulating testosterone depended only on the relative body size of a lizard; when paired, large males and small males circulated more and less testosterone, respectively. Furthermore, isolated males moved the farthest and covered the most area when shade was concentrated in a single patch, but paired males did the opposite. Because the total area of shade in each landscape was the same, these hormonal and behavioral responses of lizards reflect the ability to access shade. Thus, circulating glucocorticoids should reflect the thermal quality of an environment when researchers have controlled for other factors. Moreover, a theory of stress during thermoregulation would help ecologists anticipate physiological and behavioral responses to changing climates.
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Affiliation(s)
- Travis W Rusch
- Arizona State University, School of Life Sciences, Tempe, AZ, USA.
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6
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Dijkstra PD, Border SE. How does male-male competition generate negative frequency-dependent selection and disruptive selection during speciation? Curr Zool 2018; 64:89-99. [PMID: 29492042 PMCID: PMC5809039 DOI: 10.1093/cz/zox079] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2017] [Accepted: 12/16/2017] [Indexed: 11/14/2022] Open
Abstract
Natural selection has been shown to drive population differentiation and speciation. The role of sexual selection in this process is controversial; however, most of the work has centered on mate choice while the role of male-male competition in speciation is relatively understudied. Here, we outline how male-male competition can be a source of diversifying selection on male competitive phenotypes, and how this can contribute to the evolution of reproductive isolation. We highlight how negative frequency-dependent selection (advantage of rare phenotype arising from stronger male-male competition between similar male phenotypes compared with dissimilar male phenotypes) and disruptive selection (advantage of extreme phenotypes) drives the evolution of diversity in competitive traits such as weapon size, nuptial coloration, or aggressiveness. We underscore that male-male competition interacts with other life-history functions and that variable male competitive phenotypes may represent alternative adaptive options. In addition to competition for mates, aggressive interference competition for ecological resources can exert selection on competitor signals. We call for a better integration of male-male competition with ecological interference competition since both can influence the process of speciation via comparable but distinct mechanisms. Altogether, we present a more comprehensive framework for studying the role of male-male competition in speciation, and emphasize the need for better integration of insights gained from other fields studying the evolutionary, behavioral, and physiological consequences of agonistic interactions.
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Affiliation(s)
- Peter D Dijkstra
- Department of Biology, Central Michigan University, Mount Pleasant, MI 48859, USA
| | - Shana E Border
- Department of Biology, Central Michigan University, Mount Pleasant, MI 48859, USA
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7
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Chamorro-Florescano IA, Favila ME, Macías-Ordóñez R. Contests over reproductive resources in female roller beetles: Outcome predictors and sharing as an option. PLoS One 2017; 12:e0182931. [PMID: 28796846 PMCID: PMC5552088 DOI: 10.1371/journal.pone.0182931] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2016] [Accepted: 07/26/2017] [Indexed: 11/24/2022] Open
Abstract
Fights among females are frequent, although less attention has been placed on them than on male fights. They arise when females compete for food, oviposition, mates, brooding sites, or access to resources which increase offspring survival. It has been shown that the outcome of female fights may be less predictable by asymmetries in resource holding power, than in male fights. Male roller beetles fight over food resources, food balls, needed for mating and nesting, and it has been show in some species that asymmetries in reproductive experience and resource holding power in terms of size predict fight outcome, including ties in which contenders cut and split the food ball. In this study, we tested the influence of asymmetries in reproductive status (experience) and body size on female fight outcome in the carrion roller beetle Canthon cyanellus cyanellus. As predicted, and as previously found for males of the same species, female reproductive status of both contenders and relative size predict fight outcome. Larger and reproductively experienced contenders have a higher probability of winning. Furthermore, ties are more likely in fights involving opposing asymmetries (vgr. Large reproductively naïve owner versus small reproductively experienced intruder). Also as predicted, food ball splitting is more likely to be started by the predicted loser. This mode of resource sharing may be the result of a fighting strategy in which the costs of continuing to fight are greater than the benefits of not splitting, if a fraction of the disputed resource is more than the minimum needed for the present reproductive needs, and reduces costs associated to a longer fight.
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Affiliation(s)
| | - Mario E. Favila
- Red de Ecoetología, Instituto de Ecología A.C., Xalapa, Veracruz, Mexico
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8
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Punish the thief-coevolution of defense and cautiousness stabilizes ownership. Behav Ecol Sociobiol 2017; 71:102. [PMID: 28706342 PMCID: PMC5486837 DOI: 10.1007/s00265-017-2330-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2017] [Revised: 05/15/2017] [Accepted: 05/18/2017] [Indexed: 11/17/2022]
Abstract
Abstract Ownership of non-controllable resources usually has to be maintained by costly defense against competitors. Whether defense and thus ownership pays in terms of fitness depends on its effectiveness in preventing theft. We show that if the owners’ willingness to defend varies in the population and information about it is available to potential thieves then the ability to react to this information and thus avoid being attacked by the owner is selected for. This can lead to a positive evolutionary feedback between cautiousness in intruders and aggressiveness in owners. This feedback can maintain ownership when the actual direct effectiveness of defense in reducing theft is very low or even absent, effectively turning defense into punishment. We conclude that the deterrence effect of defense in many situations could be stronger than that of prevention and that for many real-world scenarios the purpose of defense of resources might be to punish rather than to drive away intruders. Significance statement Many animals defend resources against conspecifics. Resource defense can usually only evolve if its costs are paid for by foiling attempts at theft. We show that if potential thieves can detect differences in aggressiveness between owners then cautious intruders and aggressive owners coevolve so that in the end even ineffective defense deters thieves and maintains ownership. This result greatly extends the number of situations in which we expect resource defense to evolve and has the potential to unify the concepts of defense and punishment.
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9
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Lee AEG, Cowlishaw G. Switching spatial scale reveals dominance-dependent social foraging tactics in a wild primate. PeerJ 2017; 5:e3462. [PMID: 28674647 PMCID: PMC5494171 DOI: 10.7717/peerj.3462] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2017] [Accepted: 05/24/2017] [Indexed: 12/01/2022] Open
Abstract
When foraging in a social group, individuals are faced with the choice of sampling their environment directly or exploiting the discoveries of others. The evolutionary dynamics of this trade-off have been explored mathematically through the producer-scrounger game, which has highlighted socially exploitative behaviours as a major potential cost of group living. However, our understanding of the tight interplay that can exist between social dominance and scrounging behaviour is limited. To date, only two theoretical studies have explored this relationship systematically, demonstrating that because scrounging requires joining a competitor at a resource, it should become exclusive to high-ranking individuals when resources are monopolisable. In this study, we explore the predictions of this model through observations of the natural social foraging behaviour of a wild population of chacma baboons (Papio ursinus). We collected data through over 800 h of focal follows of 101 adults and juveniles across two troops over two 3-month periods. By recording over 7,900 social foraging decisions at two spatial scales we show that, when resources are large and economically indefensible, the joining behaviour required for scrounging can occur across all social ranks. When, in contrast, dominant individuals can aggressively appropriate a resource, such joining behaviour becomes increasingly difficult to employ with decreasing social rank because adult individuals can only join others lower ranking than themselves. Our study supports theoretical predictions and highlights potentially important individual constraints on the ability of individuals of low social rank to use social information, driven by competition with dominant conspecifics over monopolisable resources.
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Affiliation(s)
- Alexander E G Lee
- Department of Zoology, University of Oxford, Oxford, United Kingdom.,The Institute of Zoology, Zoological Society of London, London, United Kingdom.,Centre of Excellence in Biological Interactions, Department of Biological and Environmental Sciences, University of Jyväskylä, Jyväskylä, Finland
| | - Guy Cowlishaw
- The Institute of Zoology, Zoological Society of London, London, United Kingdom
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10
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The effect of fight cost structure on fighting behaviour involving simultaneous decisions and variable investment levels. J Math Biol 2017. [PMID: 28638944 DOI: 10.1007/s00285-017-1149-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
In the "producer-scrounger" model, a producer discovers a resource and is in turn discovered by a second individual, the scrounger, who attempts to steal it. This resource can be food or a territory, and in some situations, potentially divisible. In a previous paper we considered a producer and scrounger competing for an indivisible resource, where each individual could choose the level of energy that they would invest in the contest. The higher the investment, the higher the probability of success, but also the higher the costs incurred in the contest. In that paper decisions were sequential with the scrounger choosing their strategy before the producer. In this paper we consider a version of the game where decisions are made simultaneously. For the same cost functions as before, we analyse this case in detail, and then make comparisons between the two cases. Finally we discuss some real examples with potentially variable and asymmetric energetic investments, including intraspecific contests amongst spiders and amongst parasitoid wasps. In the case of the spiders, detailed estimates of energetic expenditure are available which demonstrate the asymmetric values assumed in our models. For the wasps the value of the resource can affect the probabilities of success of the defender and attacker, and differential energetic investment can be inferred. In general for real populations energy usage varies markedly depending upon crucial parameters extrinsic to the individual such as resource value and intrinsic ones such as age, and is thus an important factor to consider when modelling.
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11
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Garcia MJ, Ferro JM, Mattox T, Kopelic S, Marson K, Jones R, Svendsen JC, Earley RL. Phenotypic differences between the sexes in the sexually plastic mangrove rivulus fish (Kryptolebias marmoratus). ACTA ACUST UNITED AC 2016; 219:988-97. [PMID: 27030777 DOI: 10.1242/jeb.124040] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2015] [Accepted: 01/18/2016] [Indexed: 01/23/2023]
Abstract
To maximize reproductive success, many animal species have evolved functional sex change. Theory predicts that transitions between sexes should occur when the fitness payoff of the current sex is exceeded by the fitness payoff of the opposite sex. We examined phenotypic differences between the sexes in a sex-changing vertebrate, the mangrove rivulus fish (Kryptolebias marmoratus), to elucidate potential factors that might drive the 'decision' to switch sex. Rivulus populations consist of self-fertilizing hermaphrodites and males. Hermaphrodites transition into males under certain environmental conditions, affording us the opportunity to generate 40 hermaphrodite-male pairs where, within a pair, individuals possessed identical genotypes despite being different sexes. We quantified steroid hormone levels, behavior (aggression and risk taking), metabolism and morphology (organ masses). We found that hermaphrodites were more aggressive and risk averse, and had higher maximum metabolic rates and larger gonadosomatic indices. Males had higher steroid hormone levels and showed correlations among hormones that hermaphrodites lacked. Males also had greater total mass and somatic body mass and possessed considerable fat stores. Our findings suggest that there are major differences between the sexes in energy allocation, with hermaphrodites exhibiting elevated maximum metabolic rates, and showing evidence of favoring investments in reproductive tissues over somatic growth. Our study serves as the foundation for future research investigating how environmental challenges affect both physiology and reproductive investment and, ultimately, how these changes dictate the transition between sexes.
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Affiliation(s)
- Mark J Garcia
- Department of Biological Sciences, University of Alabama, Box 870344, Tuscaloosa, AL 35473, USA
| | - Jack M Ferro
- Department of Biological Sciences, University of Alabama, Box 870344, Tuscaloosa, AL 35473, USA
| | - Tyler Mattox
- Department of Biological Sciences, University of Alabama, Box 870344, Tuscaloosa, AL 35473, USA
| | - Sydney Kopelic
- Department of Biological Sciences, University of Alabama, Box 870344, Tuscaloosa, AL 35473, USA
| | - Kristine Marson
- Department of Biological Sciences, University of Alabama, Box 870344, Tuscaloosa, AL 35473, USA
| | - Ryan Jones
- Department of Biological Sciences, University of Alabama, Box 870344, Tuscaloosa, AL 35473, USA
| | - Jon C Svendsen
- Interdisciplinary Centre of Marine and Environmental Research (CIIMAR), University of Porto, 4050-123 Porto, Portugal Section for Ecosystem based Marine Management, National Institute of Aquatic Resources (DTU Aqua), Technical University of Denmark, 2920 Charlottenlund, Denmark
| | - Ryan L Earley
- Department of Biological Sciences, University of Alabama, Box 870344, Tuscaloosa, AL 35473, USA
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12
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Vivancos A, Closs G, Tentelier C. Are 2D space-use analyses adapted to animals living in 3D environments? A case study on a fish shoal. Behav Ecol 2016. [DOI: 10.1093/beheco/arw175] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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13
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Marean CW. The transition to foraging for dense and predictable resources and its impact on the evolution of modern humans. Philos Trans R Soc Lond B Biol Sci 2016; 371:20150239. [PMID: 27298470 PMCID: PMC4920296 DOI: 10.1098/rstb.2015.0239] [Citation(s) in RCA: 78] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/06/2016] [Indexed: 11/12/2022] Open
Abstract
Scientists have identified a series of milestones in the evolution of the human food quest that are anticipated to have had far-reaching impacts on biological, behavioural and cultural evolution: the inclusion of substantial portions of meat, the broad spectrum revolution and the transition to food production. The foraging shift to dense and predictable resources is another key milestone that had consequential impacts on the later part of human evolution. The theory of economic defendability predicts that this shift had an important consequence-elevated levels of intergroup territoriality and conflict. In this paper, this theory is integrated with a well-established general theory of hunter-gatherer adaptations and is used to make predictions for the sequence of appearance of several evolved traits of modern humans. The distribution of dense and predictable resources in Africa is reviewed and found to occur only in aquatic contexts (coasts, rivers and lakes). The palaeoanthropological empirical record contains recurrent evidence for a shift to the exploitation of dense and predictable resources by 110 000 years ago, and the first known occurrence is in a marine coastal context in South Africa. Some theory predicts that this elevated conflict would have provided the conditions for selection for the hyperprosocial behaviours unique to modern humans.This article is part of the themed issue 'Major transitions in human evolution'.
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Affiliation(s)
- Curtis W Marean
- School of Human Evolution and Social Change, Institute of Human Origins, Arizona State University, PO Box 872402, Tempe, AZ 85287-2402, USA Centre for Coastal Palaeoscience, Nelson Mandela Metropolitan University, Port Elizabeth, Eastern Cape 6031, South Africa
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14
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Plastic territoriality in group-living chestnut-crowned babblers: roles of resource value, holding potential and predation risk. Anim Behav 2015. [DOI: 10.1016/j.anbehav.2014.12.012] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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15
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The effect of fight cost structure on fighting behaviour. J Math Biol 2014; 71:979-96. [PMID: 25465400 DOI: 10.1007/s00285-014-0848-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2014] [Revised: 11/07/2014] [Indexed: 10/24/2022]
Abstract
A common feature of animal populations is the stealing by animals of resources such as food from other animals. This has previously been the subject of a range of modelling approaches, one of which is the so called "producer-scrounger" model. In this model a producer finds a resource that takes some time to be consumed, and some time later a (generally) conspecific scrounger discovers the producer with its resource and potentially attempts to steal it. In this paper we consider a variant of this scenario where each individual can choose to invest an amount of energy into this contest, and the level of investment of each individual determines the probability of it winning the contest, but also the additional cost it has to bear. We analyse the model for a specific set of cost functions and maximum investment levels and show how the evolutionarily stable behaviour depends upon them. In particular we see that for high levels of maximum investment, the producer keeps the resource without a fight for concave cost functions, but for convex functions the scrounger obtains the resource (albeit at some cost).
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16
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Stears K, Kerley GIH, Shrader AM. Group-living herbivores weigh up food availability and dominance status when making patch-joining decisions. PLoS One 2014; 9:e109011. [PMID: 25271889 PMCID: PMC4182780 DOI: 10.1371/journal.pone.0109011] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2014] [Accepted: 08/18/2014] [Indexed: 11/23/2022] Open
Abstract
Two key factors that influence the foraging behaviour of group-living herbivores are food availability and individual dominance status. Yet, how the combination of these factors influences the patch-joining decisions of individuals foraging within groups has scarcely been explored. To address this, we focused on the patch-joining decisions of group-living domestic goats (Capra hircus). When individuals were tested against the top four ranked goats of the herd, we found that at patches with low food availability they avoided these dominant patch-holders and only joined subordinates (i.e. costs outweighed benefits). However, as the amount of food increased, the avoidance of the top ranked individuals declined. Specifically, goats shifted and joined the patch of an individual one dominance rank higher than the previous dominant patch holder when the initial quantity of food in the new patch was twice that of the lower ranking individual’s patch (i.e. benefits outweighed costs). In contrast, when individuals chose between patches held by dominant goats, other than the top four ranked goats, and subordinate individuals, we found that they equally joined the dominant and subordinate patch-holders. This joining was irrespective of the dominance gap, absolute rank of the dominant patch-holder, sex or food availability (i.e. benefits outweighed costs). Ultimately, our results highlight that herbivores weigh up the costs and benefits of both food availability and patch-holder dominance status when making patch-joining decisions. Furthermore, as the initial quantity of food increases, food availability becomes more important than dominance with regard to influencing patch-joining decisions.
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Affiliation(s)
- Keenan Stears
- School of Life Sciences, University of KwaZulu-Natal, Pietermaritzburg, South Africa
- * E-mail:
| | - Graham I. H. Kerley
- Centre for African Conservation Ecology, Department of Zoology, Nelson Mandela Metropolitan University, Port Elizabeth, South Africa
| | - Adrian M. Shrader
- School of Life Sciences, University of KwaZulu-Natal, Pietermaritzburg, South Africa
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17
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Arbilly M, Weissman DB, Feldman MW, Grodzinski U. An arms race between producers and scroungers can drive the evolution of social cognition. ACTA ACUST UNITED AC 2014; 25:487-495. [PMID: 24822021 DOI: 10.1093/beheco/aru002] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2013] [Revised: 11/28/2013] [Accepted: 12/19/2013] [Indexed: 11/12/2022]
Abstract
The "social intelligence hypothesis" states that the need to cope with complexities of social life has driven the evolution of advanced cognitive abilities. It is usually invoked in the context of challenges arising from complex intragroup structures, hierarchies, and alliances. However, a fundamental aspect of group living remains largely unexplored as a driving force in cognitive evolution: the competition between individuals searching for resources (producers) and conspecifics that parasitize their findings (scroungers). In populations of social foragers, abilities that enable scroungers to steal by outsmarting producers, and those allowing producers to prevent theft by outsmarting scroungers, are likely to be beneficial and may fuel a cognitive arms race. Using analytical theory and agent-based simulations, we present a general model for such a race that is driven by the producer-scrounger game and show that the race's plausibility is dramatically affected by the nature of the evolving abilities. If scrounging and scrounging avoidance rely on separate, strategy-specific cognitive abilities, arms races are short-lived and have a limited effect on cognition. However, general cognitive abilities that facilitate both scrounging and scrounging avoidance undergo stable, long-lasting arms races. Thus, ubiquitous foraging interactions may lead to the evolution of general cognitive abilities in social animals, without the requirement of complex intragroup structures.
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Affiliation(s)
- Michal Arbilly
- Department of Biology, Stanford University , Gilbert Hall, 371 Serra Mall, Stanford, CA 94305 , USA
| | - Daniel B Weissman
- Institute of Science and Technology Austria , Am Campus 1, 3400 Klosterneuburg , Austria , and
| | - Marcus W Feldman
- Department of Biology, Stanford University , Gilbert Hall, 371 Serra Mall, Stanford, CA 94305 , USA
| | - Uri Grodzinski
- Department of Psychology, University of Cambridge , Downing Street, Cambridge CB2 3EB , UK
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18
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Chabot-Hanowell B, Smith EA. 5 Territorial and Nonterritorial Routes to Power: Reconciling Evolutionary Ecological, Social Agency, and Historicist Approaches. ACTA ACUST UNITED AC 2013. [DOI: 10.1111/apaa.12004] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Banks SC, Lindenmayer DB, Wood JT, McBurney L, Blair D, Blyton MDJ. Can individual and social patterns of resource use buffer animal populations against resource decline? PLoS One 2013; 8:e53672. [PMID: 23320100 PMCID: PMC3539978 DOI: 10.1371/journal.pone.0053672] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2012] [Accepted: 12/03/2012] [Indexed: 11/30/2022] Open
Abstract
Species in many ecosystems are facing declines of key resources. If we are to understand and predict the effects of resource loss on natural populations, we need to understand whether and how the way animals use resources changes under resource decline. We investigated how the abundance of arboreal marsupials varies in response to a critical resource, hollow-bearing trees. Principally, we asked what mechanisms mediate the relationship between resources and abundance? Do animals use a greater or smaller proportion of the remaining resource, and is there a change in cooperative resource use (den sharing), as the availability of hollow trees declines? Analyses of data from 160 sites surveyed from 1997 to 2007 showed that hollow tree availability was positively associated with abundance of the mountain brushtail possum, the agile antechinus and the greater glider. The abundance of Leadbeater’s possum was primarily influenced by forest age. Notably, the relationship between abundance and hollow tree availability was significantly less than 1∶1 for all species. This was due primarily to a significant increase by all species in the proportional use of hollow-bearing trees where the abundance of this resource was low. The resource-sharing response was weaker and inconsistent among species. Two species, the mountain brushtail possum and the agile antechinus, showed significant but contrasting relationships between the number of animals per occupied tree and hollow tree abundance. The discrepancies between the species can be explained partly by differences in several aspects of the species’ biology, including body size, types of hollows used and social behaviour as it relates to hollow use. Our results show that individual and social aspects of resource use are not always static in response to resource availability and support the need to account for dynamic resource use patterns in predictive models of animal distribution and abundance.
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Affiliation(s)
- Sam C Banks
- The Fenner School of Environment and Society, The Australian National University, Canberra, Australian Capital Territory, Australia.
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Hinsch M, Pen I, Komdeur J. Evolution of defense against depletion of local food resources in a mechanistic foraging model. Behav Ecol 2012. [DOI: 10.1093/beheco/ars160] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Hadjichrysanthou C, Broom M. When should animals share food? Game theory applied to kleptoparasitic populations with food sharing. Behav Ecol 2012. [DOI: 10.1093/beheco/ars061] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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Bijleveld AI, Folmer EO, Piersma T. Experimental evidence for cryptic interference among socially foraging shorebirds. Behav Ecol 2012. [DOI: 10.1093/beheco/ars034] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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Banks SC, Lindenmayer DB, McBurney L, Blair D, Knight EJ, Blyton MDJ. Kin selection in den sharing develops under limited availability of tree hollows for a forest marsupial. Proc Biol Sci 2011; 278:2768-76. [PMID: 21288953 DOI: 10.1098/rspb.2010.2657] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Animal social behaviour is not static with regard to environmental change. Flexibility in cooperative resource use may be an important response to resource decline, mediating the impacts of resource availability on fitness and demography. In forest ecosystems, hollow trees are key den resources for many species, but are declining worldwide owing to forestry. Altered patterns of den sharing may mediate the effects of the decline of this resource. We studied den-sharing interactions among hollow-dependent Australian mountain brushtail possums to investigate how spatial variation in hollow tree availability affects resource sharing and kin selection. Under reduced den availability, individuals used fewer dens and shared them less often. This suggests increased territoriality in the presence of resource competition. Further, there was a switch from kin avoidance to kin preference with decreasing hollow tree availability. This was driven primarily by a change in den sharing among siblings. The inclusive fitness benefits of den sharing with kin are likely to increase under resource-limiting conditions, but are potentially outweighed by the benefits of associating with non-relatives (avoidance of inbreeding or pathogen transmission) where dens are abundant. We discuss how predictions from social evolutionary theory can contribute to understanding animal responses to landscape change.
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Affiliation(s)
- Sam C Banks
- The Fenner School of Environment and Society, The Australian National University, Canberra, Australian Capital Territory 0200, Australia.
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Acute and chronic increases in predation risk affect the territorial behaviour of juvenile Atlantic salmon in the wild. Anim Behav 2011. [DOI: 10.1016/j.anbehav.2010.09.017] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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Ownership, size and reproductive status affect the outcome of food ball contests in a dung roller beetle: when do enemies share? Evol Ecol 2010. [DOI: 10.1007/s10682-010-9428-8] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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Population and individual consequences of breeding resource availability in the European bitterling (Rhodeus amarus). Behav Ecol Sociobiol 2010. [DOI: 10.1007/s00265-010-0921-4] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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Ecological Determinants of Social Systems. ADVANCES IN THE STUDY OF BEHAVIOR 2010. [DOI: 10.1016/s0065-3454(10)42009-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/04/2023]
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Wilson AJ, Gelin U, Perron MC, Réale D. Indirect genetic effects and the evolution of aggression in a vertebrate system. Proc Biol Sci 2009; 276:533-41. [PMID: 18842544 DOI: 10.1098/rspb.2008.1193] [Citation(s) in RCA: 120] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Aggressive behaviours are necessarily expressed in a social context, such that individuals may be influenced by the phenotypes, and potentially the genotypes, of their social partners. Consequently, it has been hypothesized that indirect genetic effects (IGEs) arising from the social environment will provide a major source of heritable variation on which selection can act. However, there has been little empirical scrutiny of this to date. Here we test this hypothesis in an experimental population of deer mice (Peromyscus maniculatus). Using quantitative genetic models of five aggression traits, we find repeatable and heritable differences in agonistic behaviours of focal individuals when presented with an opponent mouse. For three of the traits, there is also support for the presence of IGEs, and estimated correlations between direct and indirect genetic (rAO,F) effects were high. As a consequence, any selection for aggression in the focal individuals should cause evolution of the social environment as a correlated response. In two traits, strong positive rAO,F will cause the rapid evolution of aggression, while in a third case changes in the phenotypic mean will be constrained by negative covariance between direct and IGEs. Our results illustrate how classical analyses may miss important components of heritable variation, and show that a full understanding of evolutionary dynamics requires explicit consideration of the genetic component of the social environment.
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Affiliation(s)
- Alastair J Wilson
- Institute of Evolutionary Biology, University of Edinburgh, Edinburgh EH9 3JT, UK.
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Giraldeau LA, Dubois F. Chapter 2 Social Foraging and the Study of Exploitative Behavior. ADVANCES IN THE STUDY OF BEHAVIOR 2008. [DOI: 10.1016/s0065-3454(08)00002-8] [Citation(s) in RCA: 81] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
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Yates GE, Broom M. Stochastic models of kleptoparasitism. J Theor Biol 2007; 248:480-9. [PMID: 17624370 DOI: 10.1016/j.jtbi.2007.05.007] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2007] [Revised: 05/09/2007] [Accepted: 05/09/2007] [Indexed: 10/23/2022]
Abstract
In this paper, we consider a model of kleptoparasitism amongst a small group of individuals, where the state of the population is described by the distribution of its individuals over three specific types of behaviour (handling, searching for or fighting over, food). The model used is based upon earlier work which considered an equivalent deterministic model relating to large, effectively infinite, populations. We find explicit equations for the probability of the population being in each state. For any reasonably sized population, the number of possible states, and hence the number of equations, is large. These equations are used to find a set of equations for the means, variances, covariances and higher moments for the number of individuals performing each type of behaviour. Given the fixed population size, there are five moments of order one or two (two means, two variances and a covariance). A normal approximation is used to find a set of equations for these five principal moments. The results of our model are then analysed numerically, with the exact solutions, the normal approximation and the deterministic infinite population model compared. It is found that the original deterministic models approximate the stochastic model well in most situations, but that the normal approximations are better, proving to be good approximations to the exact distribution, which can greatly reduce computing time.
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Affiliation(s)
- G E Yates
- Mathematics Department, University of Sussex, Mantell Building, Falmer, Brighton BN1 9RF, UK
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