Strategic concealment of sexual identity in an estrildid finch
Langmore, N. E. and Bennett, A. T. D. 1999, Strategic concealment of sexual identity in an estrildid finch, Proceedings of the Royal Society of London series B-biological sciences, vol. 266, no. 1419, pp. 543-550.
Title
Strategic concealment of sexual identity in an estrildid finch
One explanation for the evolution of sexual monomorphism is the sexual indistinguishability hypothesis, which argues that in group-living species individuals might benefit by concealing their sex to reduce sexual competition. We tested this hypothesis in long-tailed finches Poephila acuticauda. Males and females could not be reliably distinguished morphologically or by analysis of the reflectance spectra (300-700 nm) from the plumage and bill. Males seemed unable to distinguish the sex of an unfamiliar individual in the absence of behavioural cues; they were equally likely to court and copulate with unfamiliar males and females but rarely courted familiar males. Here we report the first experimental evidence that sexual monomorphism enables strategic concealment of sex. Males were more likely to reveal their sex when faced with a solitary unfamiliar individual than a group of unfamiliar individuals. When encountering an unfamiliar male that revealed his sex, subordinate males were more likely to conceal their sex than dominant males.
Language
eng
Field of Research
059999 Environmental Sciences not elsewhere classified