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Group resource-holding potential: worker size, colony size and the outcome of contests in ants. Anim Behav 2023. [DOI: 10.1016/j.anbehav.2023.01.017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/27/2023]
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Clifton EM, Lewis PO, Jockusch E, Adams E. An experimental test of Lanchester's models of combat in the neotropical termite Nasutitermes corniger (Blattodea: Termitidae). Proc Biol Sci 2022; 289:20220343. [PMID: 35582801 PMCID: PMC9114941 DOI: 10.1098/rspb.2022.0343] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Lanchester's models of combat have been invoked to explain the mechanics of group fighting in social animals. Specifically, Lanchester's square law posits that the fighting ability of the group is proportional to the square of the number of combatants. Although used to explain a variety of ecological phenomena, the models have not been thoroughly tested. We tested the Lanchester models using group battles between colonies of the termite Nasutitermes corniger. Our main goals were to determine if mortality rates fit the Lanchester models, and if so, whether the behavioural mechanisms underlying a group's success match those used in deriving the model. We initiated battles between pairs of colonies with different ratios of fighters and recorded deaths over time. We found that the numerically larger army has an advantage, but that the advantage is not as pronounced as predicted by Lanchester's square law. We also video-recorded battles to analyse individual behaviour, which did not support the mechanisms invoked by Lanchester. Instead, the killing power of an individual is increased by the presence of nest-mates, giving the larger group a disproportionate advantage. Although the behavioural mechanisms leading to the advantage may differ, our results still support some of the proposed ecological phenomena.
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Affiliation(s)
- Elizabeth M. Clifton
- Department of Ecology and Evolutionary Biology, University of Connecticut, Storrs, CT 06269-3043, USA
| | - Paul O. Lewis
- Department of Ecology and Evolutionary Biology, University of Connecticut, Storrs, CT 06269-3043, USA
| | - Elizabeth Jockusch
- Department of Ecology and Evolutionary Biology, University of Connecticut, Storrs, CT 06269-3043, USA
| | - Eldridge Adams
- Department of Ecology and Evolutionary Biology, University of Connecticut, Storrs, CT 06269-3043, USA
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Caton NR, Hannan J, Dixson BJW. Facial width-to-height ratio predicts fighting success: A direct replication and extension of Zilioli et al. (2014). Aggress Behav 2022; 48:449-465. [PMID: 35262921 PMCID: PMC9544882 DOI: 10.1002/ab.22027] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2020] [Revised: 12/27/2021] [Accepted: 02/21/2022] [Indexed: 12/24/2022]
Abstract
Zilioli et al. (2014) were the first to show an association between male facial width‐to‐height ratio (fWHR) and physical aggression and fighting ability in professional mixed‐martial‐arts fighters. Here, we re‐examined this relationship by replicating (using all original measures) and extending (using 23 new variables related to fighting performance) Zilioli et al. (2014) in a statistically well‐powered sample of 520 fighters using automatic and manual measures of the fWHR involving both eyelid and eyebrow landmarks, used interchangeably in previous reports (Studies 1–2). Most importantly, we successfully replicated Zilioli et al.'s (2014) central finding that fighters' fWHR, when manually calculated using the eyebrow landmark, predicted their fighting success (p = .004, controlling for body mass index and total fights). Consistent with past criticisms of using fight rather than fighter data to examine fighting success, which have argued that individual fights can be suddenly and unexpectedly determined and do not capture an individual's overall ability to succeed, Study 3 (N = 1367 fights) found no association between fWHR and singular victories. Studies 1–3 showed continual evidence that larger fWHRs were associated with grappling abilities, even after controlling for demographic and allometric factors. Strikingly, Study 3 discovered associations between all fWHR measures and grappling skill that remained robust before and after controlling for 17 different control variables. We discuss that grappling, or the act of taking down an opponent, involves a more aggressive, close‐combat approach than does striking. Combined, these results offer additional support for the argument that fWHR may have been shaped by sexual selection.
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Affiliation(s)
- Neil R. Caton
- School of Psychology University of Queensland Brisbane Queensland Australia
| | - John Hannan
- School of Psychology University of Queensland Brisbane Queensland Australia
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Intraspecific Relationships and Nest Mound Shape Are Affected by Habitat Features in Introduced Populations of the Red Wood Ant Formica paralugubris. INSECTS 2022; 13:insects13020198. [PMID: 35206771 PMCID: PMC8875456 DOI: 10.3390/insects13020198] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/21/2021] [Revised: 02/03/2022] [Accepted: 02/10/2022] [Indexed: 02/05/2023]
Abstract
Simple Summary Red wood ants (Formica rufa goup) are dominant ant species widespread in the Eurasian continent. These species have a strong ecological impact on the habitats they dwell in, being top-ranked predators. One of the most striking features of these ants is represented by the large nest mounds they build. In this study, we investigated how nest mound shape and colony organization of imported populations of Formica paralugubris varied in three different habitat types. We found that nest mounds differed in size, number and shape in the three habitats. In all the three sites, nests were connected by trails of workers, but the size of these nest-networks differed. We also investigated the pattern of intraspecific aggression among ants from different nests, and we showed that aggressiveness was higher within each population than between separate populations, a finding in line with a ‘nasty neighbor’ behavior. Abstract Ants belonging to the Formica rufa group build large nest mounds, which aid their survival during severe winters. We investigated whether different environmental features of the habitats affected the nest mound shape and the population structure. We assessed the shape of all the nest mounds and mapped inter-nest trails connecting mounds for three imported populations of Formica paralugubris in three forest habitats: fir-dominated, beech-dominated, and a mixture of fir and beech. Single-nest mounds were averagely smaller and flatter in the beech-dominated forest, probably because of lighter building materials. Nonetheless, by summing the volumes of all interconnected nests, the size was similar among all three sites. In fir- and beech-dominated forests, large nests were also central in the networks, suggesting a central place foraging model with these nests as reference. We finally performed aggression tests, and found that aggressiveness was significantly higher among nests belonging to the same population than between populations. The results highlight the plasticity of the species to adapt nest and colony structure to different environments. Additionally, it appears that none of these populations is unicolonial, as observed in various alpine sites, there and the observed patterns of aggression are coherent with the ‘nasty neighbor’ effect.
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Liu PC, Hao DJ, Hu W, Wei JR, Wang JJ. Life history of aggression in Anastatus disparis (Hymenoptera: Eupelmidae) with extreme male-male combat. BULLETIN OF ENTOMOLOGICAL RESEARCH 2021; 111:146-152. [PMID: 32677606 DOI: 10.1017/s0007485320000413] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Aggressive behaviour is common in animals and typically has lifetime consequences. As younger males have higher residual reproductive value than older males and lose more from injuries than older males do, the propensity for fighting tends to increase with age in many empirical reports and species. However, fighting patterns in those empirical reports cannot confirm the hypothesis that individuals cannot readily inflict injuries on their opponents. To address this shortcoming, a parasitoid wasp species, Anastatus disparis (Hymenoptera: Eupelmidae), was used as an experimental model to explore the characteristics of aggression from a life-history perspective; this wasp exhibits extreme fighting, resulting in contestants experiencing injury and death. Results showed that the energetic costs of fighting to injury significantly shortened life and caused the loss of most mating ability. Inconsistent with general predictions, the frequency and intensity of fighting in A. disparis significantly decreased with male age. Further study results showed significantly more young males were received by and successfully mated with virgin females, and most genes related to energy metabolism were downregulated in aged males. Our study provided supporting evidence that young A. disparis males show more aggression likely because of their resource holding potential and sexual attractiveness decline with age.
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Affiliation(s)
- Peng-Cheng Liu
- The College of Ecology and Environment, Anhui Normal University, Anhui Province, China
| | - De-Jun Hao
- The College of Forestry, Nanjing Forestry University, Jiangsu Province, China
| | - Wei Hu
- The College of Ecology and Environment, Anhui Normal University, Anhui Province, China
| | - Jian-Rong Wei
- The College of Life Science, Hebei University, Hebei Province, China
| | - Jian-Jun Wang
- Liaoning Academy of Forestry Science, Shenyang Province, China
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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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Task partitioning in ants lacking discrete morphological worker subcastes. Behav Ecol Sociobiol 2020. [DOI: 10.1007/s00265-020-02845-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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Brown M. Detecting an Effect of Group Size on Individual Responses to Neighboring Groups in Gray-Cheeked Mangabeys (Lophocebus albigena). INT J PRIMATOL 2020. [DOI: 10.1007/s10764-020-00144-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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Orbell PA, Potter JR, Elgar MA. Collective displays as signals of relative colony size: meat ants, Iridomyrmex purpureus, are economical with the truth. Anim Behav 2020. [DOI: 10.1016/j.anbehav.2019.10.022] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Černý D, Lee K, Medal J, Blumstein DT. Applying Lanchester’s laws to the interspecific competition of coral reef fish. Behav Ecol 2018. [DOI: 10.1093/beheco/ary182] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Affiliation(s)
- David Černý
- Department of Ecology and Evolutionary Biology, University of California, Los Angeles, CA, USA
- Department of Geophysical Sciences, University of Chicago, Chicago, IL, USA
| | - Kristen Lee
- Department of Ecology and Evolutionary Biology, University of California, Los Angeles, CA, USA
- Department of Ecology and Evolutionary Biology, University of California, Los Angeles, CA, USA
| | - Jocelyn Medal
- Department of Ecology and Evolutionary Biology, University of California, Los Angeles, CA, USA
- Department of Ecology and Evolutionary Biology, University of California, Los Angeles, CA, USA
| | - Daniel T Blumstein
- Department of Ecology and Evolutionary Biology, University of California, Los Angeles, CA, USA
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Behavioural correlates of group size and group persistence in the African ice rat Otomys sloggetti robertsi. Behav Ecol Sociobiol 2017. [DOI: 10.1007/s00265-017-2293-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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Van Belle S, Scarry CJ. Individual participation in intergroup contests is mediated by numerical assessment strategies in black howler and tufted capuchin monkeys. Philos Trans R Soc Lond B Biol Sci 2016; 370:20150007. [PMID: 26503680 DOI: 10.1098/rstb.2015.0007] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Asymmetries in resource-holding potential between opposing groups frequently determine outcomes of intergroup contests. Since both numerical superiority and high intergroup dominance rank may confer competitive advantages, group members should benefit from assessing the relative strength of rivals prior to engaging in defensive displays. However, differences in individual assessment may emerge when cost-benefit trade-offs differ among group members. We examine the influence of numerical superiority and intergroup dominance relationships on individual participation in intergroup encounters in black howler monkeys (Alouatta pigra) and tufted capuchin monkeys (Sapajus nigritus). Black howlers responded with longer vocal displays during encounters with neighbours with an equal number of resident males, while tufted capuchins increased their participation with increasing relative male group size. Within each species, males and females responded similarly to varying numerical odds, suggesting that despite pay-off asymmetries between males and females, both sexes were similarly influenced by numerical asymmetries in deciding to participate in collective group defence. Whereas the outcome of contests among tufted capuchins was determined by relative male group size, reflected in a pronounced intergroup dominance hierarchy, the absence of dominance relationships among black howler groups may have provoked prolonged vocal displays in order to assess rival groups with matching competitive abilities.
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Affiliation(s)
- Sarie Van Belle
- Department of Anthropology, University of Texas at Austin, 2201 Speedway C3200, Austin, TX 78712, USA
| | - Clara J Scarry
- Department of Anthropology, University of Texas at Austin, 2201 Speedway C3200, Austin, TX 78712, USA Department of Anthropology, Stony Brook University, Social and Behavioral Sciences Building S-501, Stony Brook, NY 11794-4364, USA
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Santarlasci A, Martelloni G, Frizzi F, Santini G, Bagnoli F. Modeling warfare in social animals: a "chemical" approach. PLoS One 2014; 9:e111310. [PMID: 25369269 PMCID: PMC4219847 DOI: 10.1371/journal.pone.0111310] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2013] [Accepted: 09/30/2014] [Indexed: 12/03/2022] Open
Abstract
We present here a general method for modelling the dynamics of battles among social animals. The proposed method exploits the procedures widely used to model chemical reactions, but still uncommon in behavioural studies. We applied this methodology to the interpretation of experimental observations of battles between two species of ants (Lasius neglectus and Lasius paralienus), but this scheme may have a wider applicability and can be extended to other species as well. We performed two types of experiment labelled as interaction and mortality. The interaction experiments are designed to obtain information on the combat dynamics and lasted one hour. The mortality ones provide information on the casualty rates of the two species and lasted five hours. We modelled the interactions among ants using a chemical model which considers the single ant individuals and fighting groups analogously to atoms and molecules. The mean-field behaviour of the model is described by a set of non-linear differential equations. We also performed stochastic simulations of the corresponding agent-based model by means of the Gillespie event-driven integration scheme. By fitting the stochastic trajectories with the deterministic model, we obtained the probability distribution of the reaction parameters. The main result that we obtained is a dominance phase diagram, that gives the average trajectory of a generic battle, for an arbitrary number of opponents. This phase diagram was validated with some extra experiments. With respect to other war models (e.g., Lanchester's ones), our chemical model considers all phases of the battle and not only casualties. This allows a more detailed description of the battle (with a larger number of parameters), allowing the development of more sophisticated models (e.g., spatial ones), with the goal of distinguishing collective effects from the strategic ones.
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Affiliation(s)
- Alisa Santarlasci
- Department of Information Engineering, University of Florence, Firenze, Italy
- Center for the Study of Complex Dynamics (CSDC), University of Florence, Sesto Fiorentino (FI), Italy
| | - Gianluca Martelloni
- Department Physics and Astronomy, University of Florence, Sesto Fiorentino (FI), Italy
- Center for the Study of Complex Dynamics (CSDC), University of Florence, Sesto Fiorentino (FI), Italy
| | - Filippo Frizzi
- Department of Biology, University of Florence, Sesto Fiorentino (FI), Italy
| | - Giacomo Santini
- Department of Biology, University of Florence, Sesto Fiorentino (FI), Italy
| | - Franco Bagnoli
- Department Physics and Astronomy, University of Florence, Sesto Fiorentino (FI), Italy
- Center for the Study of Complex Dynamics (CSDC), University of Florence, Sesto Fiorentino (FI), Italy
- National Institute of Nuclear Physics (INFN), sez. Firenze, Italy
- * E-mail:
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Briffa M. What determines the duration of war? Insights from assessment strategies in animal contests. PLoS One 2014; 9:e108491. [PMID: 25247403 PMCID: PMC4172633 DOI: 10.1371/journal.pone.0108491] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2014] [Accepted: 08/28/2014] [Indexed: 11/18/2022] Open
Abstract
Interstate wars and animal contests both involve disputed resources, restraint and giving up decisions. In both cases it seems illogical for the weaker side to persist in the conflict if it will eventually lose. In the case of animal contests analyses of the links between opponent power and contest duration have provided insights into what sources of information are available to fighting animals. I outline the theory of information use during animal contests and describe a statistical framework that has been used to distinguish between two strategies that individuals use to decide whether to persist or quit. I then apply this framework to the analysis of interstate wars. War duration increases with the power of winners and losers. These patterns provide no support for the idea that wars are settled on the basis of mutual assessment of capabilities but indicate that settlement is based on attrition. In contrast to most animal contests, war duration is as closely linked to the power of the winning side as to that of the losing side. Overall, this analysis highlights a number of similarities between animal contests and interstate war, indicating that both could be investigated using similar conceptual frameworks.
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Affiliation(s)
- Mark Briffa
- School of Marine Science & Engineering, Plymouth University, Plymouth, United Kingdom
- * E-mail:
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Stulp G, Kordsmeyer T, Buunk AP, Verhulst S. Increased aggression during human group contests when competitive ability is more similar. Biol Lett 2012; 8:921-3. [PMID: 22896272 DOI: 10.1098/rsbl.2012.0591] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Theoretical analyses and empirical studies have revealed that conflict escalation is more likely when individuals are more similar in resource-holding potential (RHP). Conflicts can also occur between groups, but it is unknown whether conflicts also escalate more when groups are more similar in RHP. We tested this hypothesis in humans, using data from two professional sports competitions: football (the Bundesliga, the German first division of football) and basketball (the NBA, the North American National Basketball Association). We defined RHP based on the league ranks of the teams involved in the competition (i.e. their competitive ability) and measured conflict escalation by the number of fouls committed. We found that in both sports the number of fouls committed increased when the difference in RHP was smaller. Thus, we provide what is to our best knowledge the first evidence that, as in conflicts between individuals, conflicts escalate more when groups are more similar in RHP.
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Affiliation(s)
- Gert Stulp
- Department of Psychology, University of Groningen, Groningen, The Netherlands.
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