Species recognition in zebra finches: testing the effects of sex, sensory modalities, and social ontogeny

Abstract

Species recognition is an integral component of mate selection and must occur in all sexually reproducing organisms to avoid costly hybridisation. Species recognition abilities may be comprised of both innate components and experience during ontogeny through the learning of visual, acoustic, and other sensory species-specific cues. But how greatly is the ability to recognise one‟s own species (conspecifics) over others (heterospecifics) dependent on the phylogeographic relationship of the array of potential species as social partners and to what extent is the discriminatory behaviour modulated by subject ontogeny versus species identity? Using a model system, which is widely studied in all disciplines of avian research, the zebra finch (Taeniopygia guttata castanotis), I aimed to investigate the visual and acoustic cues involved in conspecific recognition by both female and male individuals of this species. I used an array of previously untested phylogeographically relevant estrildid heterospecifics as my stimuli and tested subjects of diverse experimental ontogenetic treatments. By scoring a wide-selection of measured behavioural responses my research indicates that female and male zebra finches prefer live conspecifics over live phylogeographically relevant heterospecific stimuli and this preference is more consistent by females than males. Female zebra finches rely on both visual and acoustic features of potential social partners for accurate species discrimination; in this regard video playbacks or the diverse colour morphs of domesticated zebra finches may be useful tools for further experimentation. Additionally, females display significant individuality in their behavioural responses which may be relevant for pair bonding decisions made by both sexes. I further documented that normally-reared zebra finches will prefer song playbacks of their own species but that both rearing in an indoor restricted acoustic environment of conspecifics or cross-fostering to another species will reduce discrimination preferences, although the results may depend on the behavioural metrics analysed. This dissertation is presented as a general overview with details of my specific contributions towards the work included in this thesis, followed by discrete review and data chapters, and a final general discussion.