Um conto sobre a agressividade: valor de recurso, tomada de decisão e adaptações morfológicas
Autor(a) principal: | |
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Data de Publicação: | 2017 |
Tipo de documento: | Tese |
Idioma: | por |
Título da fonte: | Manancial - Repositório Digital da UFSM |
Texto Completo: | http://repositorio.ufsm.br/handle/1/18427 |
Resumo: | Agonistic behavior is ubiquituous in nature. Hence, understanding how and why it occurs is fundamental for unravelling its influence in the evolution of behavior. The goals of this thesis are: to test the influence of predictable environmental cycles on fighting behavior, how animals decide when to quit a fight and the morphological adaptations for efficient weaponry. Two variables are typically used to determine an individual‟s motivation to fight: resource value and fighting costs. Although they are well studied, there is no information on the effects of predictable environmental cycles on these variables. Hence, in the first chapter we tested the influence of tidal cycles on the motivation and contests of the sea anemone Actinia equina. We simulated a tidal cycle in the laboratory in which we exposed a group of anemones to it but not others. We elicited fights between these groups, also measuring their startle responses to assess territory value. Our results suggest that territories with water flow are more valuable because individuals exposed to flow had: shorter startle responses, higher winning probability and longer contests. However, these individuals are also less likely to escalate their aggression levels, suggesting that fighting costs are also higher. Following that rationale, understanding how individuals make the decision to withdraw from a contest is important to understand the evolution of such behavior. Two theoretical models explain that decision: one in which the individual uses information only about himself; and the other predicts that individuals can assess each other‟s fighting ability. To test this in the second chapter, first we tested which morphological and performance traits are important for an individual to win a contest. Afterwards, we tested which model explains better the decision to withdraw in fights between males of Aegla longirostri. Our results indicate that body size and claw height are important to settle contests. Regarding the decision to withdraw, crabs seem to use a mix of both models because contest variables corroborate with the quantitative predictions of both assessment models. Crabs‟ claws are regarded as weapons in these fights, and as such, are used to subjugate opponents. Given this role, having an efficient weapon can increase the individual‟s fitness. According to theory, this efficiency has a cost: the higher the weapon efficiency, less variable will be its shape when compared to an structure that is used both to fight and to signal. In the third chapter, we investigated the shape and performance of the claw of three Aegla species that use their claws differently: one species uses only for fighting (A. longirostri), other for fighting and signaling (Aegla abtao) and the last one only for feeding (Aegla denticulata). Our data corroborate this theory: fighting claws are biomechanically efficient but with a conserved shape, whereas the fighting and signaling claw is also biomechanically efficient, but its‟ shape is more variable. Overall, we demonstrated that predictable environmental cycles are important for contest behavior, that theoretical models of assessment need to be reworked and the biomechanic efficiency constrains weapon shape. |
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Um conto sobre a agressividade: valor de recurso, tomada de decisão e adaptações morfológicasA tale of aggression: resource value, decision making and morphological adaptationsTeoria dos jogosModelos de avaliaçãoHabilidade de lutaSeleção sexualConfrontos animaisGame theoryAssessment modelsFighting abilitySexual selectionAnimal contestsCNPQ::CIENCIAS BIOLOGICAS::BIOQUIMICAAgonistic behavior is ubiquituous in nature. Hence, understanding how and why it occurs is fundamental for unravelling its influence in the evolution of behavior. The goals of this thesis are: to test the influence of predictable environmental cycles on fighting behavior, how animals decide when to quit a fight and the morphological adaptations for efficient weaponry. Two variables are typically used to determine an individual‟s motivation to fight: resource value and fighting costs. Although they are well studied, there is no information on the effects of predictable environmental cycles on these variables. Hence, in the first chapter we tested the influence of tidal cycles on the motivation and contests of the sea anemone Actinia equina. We simulated a tidal cycle in the laboratory in which we exposed a group of anemones to it but not others. We elicited fights between these groups, also measuring their startle responses to assess territory value. Our results suggest that territories with water flow are more valuable because individuals exposed to flow had: shorter startle responses, higher winning probability and longer contests. However, these individuals are also less likely to escalate their aggression levels, suggesting that fighting costs are also higher. Following that rationale, understanding how individuals make the decision to withdraw from a contest is important to understand the evolution of such behavior. Two theoretical models explain that decision: one in which the individual uses information only about himself; and the other predicts that individuals can assess each other‟s fighting ability. To test this in the second chapter, first we tested which morphological and performance traits are important for an individual to win a contest. Afterwards, we tested which model explains better the decision to withdraw in fights between males of Aegla longirostri. Our results indicate that body size and claw height are important to settle contests. Regarding the decision to withdraw, crabs seem to use a mix of both models because contest variables corroborate with the quantitative predictions of both assessment models. Crabs‟ claws are regarded as weapons in these fights, and as such, are used to subjugate opponents. Given this role, having an efficient weapon can increase the individual‟s fitness. According to theory, this efficiency has a cost: the higher the weapon efficiency, less variable will be its shape when compared to an structure that is used both to fight and to signal. In the third chapter, we investigated the shape and performance of the claw of three Aegla species that use their claws differently: one species uses only for fighting (A. longirostri), other for fighting and signaling (Aegla abtao) and the last one only for feeding (Aegla denticulata). Our data corroborate this theory: fighting claws are biomechanically efficient but with a conserved shape, whereas the fighting and signaling claw is also biomechanically efficient, but its‟ shape is more variable. Overall, we demonstrated that predictable environmental cycles are important for contest behavior, that theoretical models of assessment need to be reworked and the biomechanic efficiency constrains weapon shape.Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPESConfronto agonístico é um fenômeno ubíquo na natureza. Dada sua abrangência, entender como e o porquê ela ocorre é essencial para entendermos sua influência na evolução do comportamento. Os objetivos desta tese são: testar a influência de ciclos ambientais previsíveis nos confrontos, quais regras os crustáceos utilizam para continuar ou desistir de um confronto e as adaptações morfológicas que fazem armamentos eficientes. Duas variáveis são comumente utilizadas para determinar a motivação do animal para brigar: o valor do recurso e os custos da agressão. Apesar de bem estudadas, não há informações sobre como ciclos ambientais previsíveis influenciam essas variáveis. Por isso, no primeiro capítulo testamos a influência das marés no comportamento agressivo da anêmona do mar Actinia equina. Simulamos um ambiente de marés no laboratório, expondo algumas anêmonas ao fluxo de água e outras não, confrontando-os. Para aferirmos o valor do recurso, mensuramos o tempo da resposta de fuga. Nossos resultados sugerem que áreas com fluxo são mais valiosas, pois indivíduos nesses ambientes tiveram: tempo de resposta de fuga menor, maior probabilidade de vitória e confrontos mais longos. Contudo, esses indivíduos também são menos propensos a escalar o confronto, sugerindo também um aumento nos custos do confronto. Entender que tipo de regras os animais utilizam para permanecer ou desistir em um confronto são essenciais para entendermos a evolução desse comportamento. Dois modelos teóricos explicam essa decisão: um no qual o animal utiliza apenas informação sobre si mesmo; e outro que prediz que os animais comparam a própria habilidade de luta com a do oponente. Para testar isso no segundo capítulo, primeiro testamos quais variáveis morfológicas e de performance auxiliam um animal a vencer um confronto. Após, testamos qual modelo explica melhor confrontos entre machos de Aegla longirostri. Nossos resultados indicam que tamanho corporal e tamanho do quelípodo são importantes para determinar quem vence. Quanto à decisão de desistir do confronto, os caranguejos aparentemente utilizam uma mistura desses dois modelos, pois os confrontos corroboram tanto predições quantitativas do modelo de comparação quanto predições do modelo sem comparação. Armamentos são utilizados em confrontos para subjugar oponentes. Dado seu papel, ter um armamento eficiente pode aumentar o sucesso reprodutivo do animal. Segundo a teoria, essa eficiência tem um custo: quanto maior a eficiência menor a variabilidade de formas de um armamento quando comparado a uma estrutura mista (i.e. que é utilizada como armamento e ornamento). No terceiro capítulo, nós investigamos a relação forma com a performance do quelípodo de três espécies de Aegla com diferentes funções: uma apenas para lutas (A. longirostri), outra para lutas e sinalização (Aegla abtao) e outra somente para alimentação (Aegla denticulata). Nossos dados corroboram a teoria: quelípodos para luta são biomecanicamente eficientes, mas sua forma é pouco variável, enquanto o quelípodo misto (A. abtao) também é biomecanicamente eficiente, porém a forma é mais variável. Em suma, demonstramos que flutuações ambientais previsíveis são importantes para confrontos, que os modelos teóricos de briga precisam ser repensados e que a restrição biomecânica dos armamentos previne que aumentem a sua variabilidade morfológica.Universidade Federal de Santa MariaBrasilBioquímicaUFSMPrograma de Pós-Graduação em Biodiversidade AnimalCentro de Ciências Naturais e ExatasSantos, Sandrohttp://lattes.cnpq.br/2397252405405950Peixoto, Paulo Enrique Cardosohttp://lattes.cnpq.br/3149228650359524Santos, Eduardo da Silva Alves doshttp://lattes.cnpq.br/6113675218570628Palaoro, Alexandre Varaschin2019-09-25T21:12:36Z2019-09-25T21:12:36Z2017-02-15info:eu-repo/semantics/publishedVersioninfo:eu-repo/semantics/doctoralThesisapplication/pdfhttp://repositorio.ufsm.br/handle/1/18427porAttribution-NonCommercial-NoDerivatives 4.0 Internationalhttp://creativecommons.org/licenses/by-nc-nd/4.0/info:eu-repo/semantics/openAccessreponame:Manancial - Repositório Digital da UFSMinstname:Universidade Federal de Santa Maria (UFSM)instacron:UFSM2019-09-26T06:02:04Zoai:repositorio.ufsm.br:1/18427Biblioteca Digital de Teses e Dissertaçõeshttps://repositorio.ufsm.br/ONGhttps://repositorio.ufsm.br/oai/requestatendimento.sib@ufsm.br||tedebc@gmail.comopendoar:2019-09-26T06:02:04Manancial - Repositório Digital da UFSM - Universidade Federal de Santa Maria (UFSM)false |
dc.title.none.fl_str_mv |
Um conto sobre a agressividade: valor de recurso, tomada de decisão e adaptações morfológicas A tale of aggression: resource value, decision making and morphological adaptations |
title |
Um conto sobre a agressividade: valor de recurso, tomada de decisão e adaptações morfológicas |
spellingShingle |
Um conto sobre a agressividade: valor de recurso, tomada de decisão e adaptações morfológicas Palaoro, Alexandre Varaschin Teoria dos jogos Modelos de avaliação Habilidade de luta Seleção sexual Confrontos animais Game theory Assessment models Fighting ability Sexual selection Animal contests CNPQ::CIENCIAS BIOLOGICAS::BIOQUIMICA |
title_short |
Um conto sobre a agressividade: valor de recurso, tomada de decisão e adaptações morfológicas |
title_full |
Um conto sobre a agressividade: valor de recurso, tomada de decisão e adaptações morfológicas |
title_fullStr |
Um conto sobre a agressividade: valor de recurso, tomada de decisão e adaptações morfológicas |
title_full_unstemmed |
Um conto sobre a agressividade: valor de recurso, tomada de decisão e adaptações morfológicas |
title_sort |
Um conto sobre a agressividade: valor de recurso, tomada de decisão e adaptações morfológicas |
author |
Palaoro, Alexandre Varaschin |
author_facet |
Palaoro, Alexandre Varaschin |
author_role |
author |
dc.contributor.none.fl_str_mv |
Santos, Sandro http://lattes.cnpq.br/2397252405405950 Peixoto, Paulo Enrique Cardoso http://lattes.cnpq.br/3149228650359524 Santos, Eduardo da Silva Alves dos http://lattes.cnpq.br/6113675218570628 |
dc.contributor.author.fl_str_mv |
Palaoro, Alexandre Varaschin |
dc.subject.por.fl_str_mv |
Teoria dos jogos Modelos de avaliação Habilidade de luta Seleção sexual Confrontos animais Game theory Assessment models Fighting ability Sexual selection Animal contests CNPQ::CIENCIAS BIOLOGICAS::BIOQUIMICA |
topic |
Teoria dos jogos Modelos de avaliação Habilidade de luta Seleção sexual Confrontos animais Game theory Assessment models Fighting ability Sexual selection Animal contests CNPQ::CIENCIAS BIOLOGICAS::BIOQUIMICA |
description |
Agonistic behavior is ubiquituous in nature. Hence, understanding how and why it occurs is fundamental for unravelling its influence in the evolution of behavior. The goals of this thesis are: to test the influence of predictable environmental cycles on fighting behavior, how animals decide when to quit a fight and the morphological adaptations for efficient weaponry. Two variables are typically used to determine an individual‟s motivation to fight: resource value and fighting costs. Although they are well studied, there is no information on the effects of predictable environmental cycles on these variables. Hence, in the first chapter we tested the influence of tidal cycles on the motivation and contests of the sea anemone Actinia equina. We simulated a tidal cycle in the laboratory in which we exposed a group of anemones to it but not others. We elicited fights between these groups, also measuring their startle responses to assess territory value. Our results suggest that territories with water flow are more valuable because individuals exposed to flow had: shorter startle responses, higher winning probability and longer contests. However, these individuals are also less likely to escalate their aggression levels, suggesting that fighting costs are also higher. Following that rationale, understanding how individuals make the decision to withdraw from a contest is important to understand the evolution of such behavior. Two theoretical models explain that decision: one in which the individual uses information only about himself; and the other predicts that individuals can assess each other‟s fighting ability. To test this in the second chapter, first we tested which morphological and performance traits are important for an individual to win a contest. Afterwards, we tested which model explains better the decision to withdraw in fights between males of Aegla longirostri. Our results indicate that body size and claw height are important to settle contests. Regarding the decision to withdraw, crabs seem to use a mix of both models because contest variables corroborate with the quantitative predictions of both assessment models. Crabs‟ claws are regarded as weapons in these fights, and as such, are used to subjugate opponents. Given this role, having an efficient weapon can increase the individual‟s fitness. According to theory, this efficiency has a cost: the higher the weapon efficiency, less variable will be its shape when compared to an structure that is used both to fight and to signal. In the third chapter, we investigated the shape and performance of the claw of three Aegla species that use their claws differently: one species uses only for fighting (A. longirostri), other for fighting and signaling (Aegla abtao) and the last one only for feeding (Aegla denticulata). Our data corroborate this theory: fighting claws are biomechanically efficient but with a conserved shape, whereas the fighting and signaling claw is also biomechanically efficient, but its‟ shape is more variable. Overall, we demonstrated that predictable environmental cycles are important for contest behavior, that theoretical models of assessment need to be reworked and the biomechanic efficiency constrains weapon shape. |
publishDate |
2017 |
dc.date.none.fl_str_mv |
2017-02-15 2019-09-25T21:12:36Z 2019-09-25T21:12:36Z |
dc.type.status.fl_str_mv |
info:eu-repo/semantics/publishedVersion |
dc.type.driver.fl_str_mv |
info:eu-repo/semantics/doctoralThesis |
format |
doctoralThesis |
status_str |
publishedVersion |
dc.identifier.uri.fl_str_mv |
http://repositorio.ufsm.br/handle/1/18427 |
url |
http://repositorio.ufsm.br/handle/1/18427 |
dc.language.iso.fl_str_mv |
por |
language |
por |
dc.rights.driver.fl_str_mv |
Attribution-NonCommercial-NoDerivatives 4.0 International http://creativecommons.org/licenses/by-nc-nd/4.0/ info:eu-repo/semantics/openAccess |
rights_invalid_str_mv |
Attribution-NonCommercial-NoDerivatives 4.0 International http://creativecommons.org/licenses/by-nc-nd/4.0/ |
eu_rights_str_mv |
openAccess |
dc.format.none.fl_str_mv |
application/pdf |
dc.publisher.none.fl_str_mv |
Universidade Federal de Santa Maria Brasil Bioquímica UFSM Programa de Pós-Graduação em Biodiversidade Animal Centro de Ciências Naturais e Exatas |
publisher.none.fl_str_mv |
Universidade Federal de Santa Maria Brasil Bioquímica UFSM Programa de Pós-Graduação em Biodiversidade Animal Centro de Ciências Naturais e Exatas |
dc.source.none.fl_str_mv |
reponame:Manancial - Repositório Digital da UFSM instname:Universidade Federal de Santa Maria (UFSM) instacron:UFSM |
instname_str |
Universidade Federal de Santa Maria (UFSM) |
instacron_str |
UFSM |
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UFSM |
reponame_str |
Manancial - Repositório Digital da UFSM |
collection |
Manancial - Repositório Digital da UFSM |
repository.name.fl_str_mv |
Manancial - Repositório Digital da UFSM - Universidade Federal de Santa Maria (UFSM) |
repository.mail.fl_str_mv |
atendimento.sib@ufsm.br||tedebc@gmail.com |
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1805922070412918784 |