Mutualism benefits and the evolution of an interspecific sentry call in associations between Sociable Weavers and Fork-tailed Drongos

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dc.contributor.advisorRyan, Peter Gen_ZA
dc.contributor.advisorFlower, Thomasen_ZA
dc.contributor.authorBaigrie, Bruceen_ZA
dc.date.accessioned2014-09-22T12:00:23Z
dc.date.available2014-09-22T12:00:23Z
dc.date.issued2013en_ZA
dc.description.abstractMutualisms, where organisms benefit from cooperation, are common in nature, but payoffs are dynamic and mutualists can incur costs as well as benefits from their association. Nevertheless, selection can favour the coevolution of behaviour that increases benefits. Such coevolution can potentially result in new mutualistic behaviours. Our study considered associations between Fork-tailed Drongos (Dicrurus adsimilis), birds which use both false alarms and aggression to steal food from other species (kleptoparasitism), and their most frequent host, the Sociable Weaver (Philetairus socius). While drongos apparently gain and weavers lose from this association, we investigated whether weavers derive foraging and predator protection benefits, and whether drongos increase foraging opportunities through sentry call behaviour. When with drongos, weavers increased their foraging time and reduced vigilance. Experimental playbacks further demonstrated that drongo sentry calls attract sociable weavers, as well as increasing their foraging time and decreasing their vigilance. Weavers also resumed foraging after an alarm more quickly when sentry calls were made, but sentry calls do not appear to improve drongo false alarm success since sentry calls did not increase the likelihood weavers fled to subsequent drongo false alarms. Consequently sentry calls benefit weavers via foraging payoffs and drongos via weaver attraction and potentially by increasing opportunities for kleptoparasitism. Results demonstrate that despite costly deception between mutualists, individuals nevertheless derive benefits which may be enhanced by the coevolution of a mutually beneficial vocal signal, specific to interspecific communication.en_ZA
dc.identifier.apacitationBaigrie, B. (2013). <i>Mutualism benefits and the evolution of an interspecific sentry call in associations between Sociable Weavers and Fork-tailed Drongos</i>. (Thesis). University of Cape Town ,Faculty of Science ,Department of Biological Sciences. Retrieved from http://hdl.handle.net/11427/7641en_ZA
dc.identifier.chicagocitationBaigrie, Bruce. <i>"Mutualism benefits and the evolution of an interspecific sentry call in associations between Sociable Weavers and Fork-tailed Drongos."</i> Thesis., University of Cape Town ,Faculty of Science ,Department of Biological Sciences, 2013. http://hdl.handle.net/11427/7641en_ZA
dc.identifier.citationBaigrie, B. 2013. Mutualism benefits and the evolution of an interspecific sentry call in associations between Sociable Weavers and Fork-tailed Drongos. University of Cape Town.en_ZA
dc.identifier.ris TY - Thesis / Dissertation AU - Baigrie, Bruce AB - Mutualisms, where organisms benefit from cooperation, are common in nature, but payoffs are dynamic and mutualists can incur costs as well as benefits from their association. Nevertheless, selection can favour the coevolution of behaviour that increases benefits. Such coevolution can potentially result in new mutualistic behaviours. Our study considered associations between Fork-tailed Drongos (Dicrurus adsimilis), birds which use both false alarms and aggression to steal food from other species (kleptoparasitism), and their most frequent host, the Sociable Weaver (Philetairus socius). While drongos apparently gain and weavers lose from this association, we investigated whether weavers derive foraging and predator protection benefits, and whether drongos increase foraging opportunities through sentry call behaviour. When with drongos, weavers increased their foraging time and reduced vigilance. Experimental playbacks further demonstrated that drongo sentry calls attract sociable weavers, as well as increasing their foraging time and decreasing their vigilance. Weavers also resumed foraging after an alarm more quickly when sentry calls were made, but sentry calls do not appear to improve drongo false alarm success since sentry calls did not increase the likelihood weavers fled to subsequent drongo false alarms. Consequently sentry calls benefit weavers via foraging payoffs and drongos via weaver attraction and potentially by increasing opportunities for kleptoparasitism. Results demonstrate that despite costly deception between mutualists, individuals nevertheless derive benefits which may be enhanced by the coevolution of a mutually beneficial vocal signal, specific to interspecific communication. DA - 2013 DB - OpenUCT DP - University of Cape Town LK - https://open.uct.ac.za PB - University of Cape Town PY - 2013 T1 - Mutualism benefits and the evolution of an interspecific sentry call in associations between Sociable Weavers and Fork-tailed Drongos TI - Mutualism benefits and the evolution of an interspecific sentry call in associations between Sociable Weavers and Fork-tailed Drongos UR - http://hdl.handle.net/11427/7641 ER - en_ZA
dc.identifier.urihttp://hdl.handle.net/11427/7641
dc.identifier.vancouvercitationBaigrie B. Mutualism benefits and the evolution of an interspecific sentry call in associations between Sociable Weavers and Fork-tailed Drongos. [Thesis]. University of Cape Town ,Faculty of Science ,Department of Biological Sciences, 2013 [cited yyyy month dd]. Available from: http://hdl.handle.net/11427/7641en_ZA
dc.language.isoengen_ZA
dc.publisher.departmentDepartment of Biological Sciencesen_ZA
dc.publisher.facultyFaculty of Scienceen_ZA
dc.publisher.institutionUniversity of Cape Town
dc.titleMutualism benefits and the evolution of an interspecific sentry call in associations between Sociable Weavers and Fork-tailed Drongosen_ZA
dc.typeBachelor Thesis
dc.type.qualificationlevelHonours
dc.type.qualificationnameBScen_ZA
uct.type.filetypeText
uct.type.filetypeImage
uct.type.publicationResearchen_ZA
uct.type.resourceThesisen_ZA
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