Photoperiod modulation of aggressive behavior is independent of androgens in a tropical cichlid fish

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dc.contributor.authorGoncalves-de-Freitas, Eliane [UNESP]
dc.contributor.authorCarvalho, Thais Billalba
dc.contributor.authorOliveira, Rui F.
dc.contributor.institutionUniversidade Estadual Paulista (Unesp)
dc.contributor.institutionUniv Fed Amazonas
dc.contributor.institutionISPA Inst Univ
dc.contributor.institutionInst Gulbenkian Ciencias
dc.date.accessioned2015-03-18T15:54:10Z
dc.date.available2015-03-18T15:54:10Z
dc.date.issued2014-10-01
dc.description.abstractPhotoperiod is a major environmental cue that signals breeding conditions in animals living in temperate climates. Therefore, the activity of the reproductive (i.e. hypothalamic pituitary gonadal, HPG) axis and of the expression of reproductive behaviors, including territoriality, is responsive to changes in day length. However, at low latitudes the seasonal variation in day length decreases dramatically and photoperiod becomes less reliable as a breeding entraining cue in tropical species. In spite of this, some tropical mammals and birds have been found to still respond to small amplitude changes in photoperiod (e.g. 17 min). Here we tested the effect of 2 photoperiod regimes, referred to as long-day (LD: 16L:08D) and short-day (SD: 08L:16D), on the activity of the HPG axis, on aggressive behavior and in the androgen response to social challenges in males of the tropical cichlid fish Tilapia rendalli. For each treatment, fish were transferred from a pre-treatment photoperiod of 12L:12D to their treatment photoperiod (either LD or SD) in which they were kept for 20 days on stock tanks. Afterwards, males were isolated for 4 days in glass aquaria in order to establish territories and initial androgen levels (testosterone, T; 11-ketotestosterone, KT) were assessed. On the 4th day, territorial intrusions were promoted such that 113 of the isolated males acted as residents and another 1/3 as intruders. Territorial intrusions lasted for 1 h to test the effects of a social challenge under different photoperiod regimes. Photoperiod treatment (either SD or LD) failed to induce significant changes in the HPG activity, as measured by androgen levels and gonadosomatic index. However, SD increased the intensity of aggressive behaviors and shortened the time to settle a dominance hierarchy in an androgen-independent manner. The androgen responsiveness to the simulated territorial intrusion was only present in KT but not for T. The percent change in KT levels in response to the social challenge was different between treatments (SD > LD) and between male types (resident > intruder). The higher androgen response to a social challenge in residents under SD may be explained by the time course of the androgen response that due to the long time it takes to fight resolution under LD, might have been delayed. This result illustrates the importance of incorporating time response data in social endocrinology studies. (C) 2014 Elsevier Inc. All rights reserved.en
dc.description.affiliationUniv Estadual Paulista, BR-15054000 Sao Jose Do Rio Preto, SP, Brazil
dc.description.affiliationUNESP, Ctr Aquicultura, BR-15054000 Sao Jose Do Rio Preto, SP, Brazil
dc.description.affiliationUniv Fed Amazonas, Manaus, AM, Brazil
dc.description.affiliationISPA Inst Univ, P-1149041 Lisbon, Portugal
dc.description.affiliationInst Gulbenkian Ciencias, Champalimaud Neurosci Programme, P-2780156 Oeiras, Portugal
dc.description.affiliationUnespUniv Estadual Paulista, BR-15054000 Sao Jose Do Rio Preto, SP, Brazil
dc.description.affiliationUnespUNESP, Ctr Aquicultura, BR-15054000 Sao Jose Do Rio Preto, SP, Brazil
dc.description.sponsorshipCoordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
dc.description.sponsorshipFundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
dc.description.sponsorshipFundacao para a Ciencia e a Tecnologia (FCT, Portugal)
dc.description.sponsorshipIdFAPESP: 06/05013-0
dc.description.sponsorshipIdFundacao para a Ciencia e a Tecnologia (FCT, Portugal)RG-568-LVT-331-2352
dc.format.extent41-49
dc.identifierhttp://dx.doi.org/10.1016/j.ygcen.2014.07.024
dc.identifier.citationGeneral And Comparative Endocrinology. San Diego: Academic Press Inc Elsevier Science, v. 207, p. 41-49, 2014.
dc.identifier.doi10.1016/j.ygcen.2014.07.024
dc.identifier.issn0016-6480
dc.identifier.urihttp://hdl.handle.net/11449/116800
dc.identifier.wosWOS:000343638900007
dc.language.isoeng
dc.publisherElsevier B.V.
dc.relation.ispartofGeneral And Comparative Endocrinology
dc.relation.ispartofjcr2.564
dc.relation.ispartofsjr1,101
dc.rights.accessRightsAcesso restrito
dc.sourceWeb of Science
dc.subjectPhotoperioden
dc.subjectAndrogensen
dc.subjectChallenge hypothesisen
dc.subjectTerritorial intrusionen
dc.subjectAggressive behavioren
dc.titlePhotoperiod modulation of aggressive behavior is independent of androgens in a tropical cichlid fishen
dc.typeArtigo
dcterms.licensehttp://www.elsevier.com/about/open-access/open-access-policies/article-posting-policy
dcterms.rightsHolderElsevier B.V.

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