Post-copulatory sexual selection and the Zebra Finch

Intra‐specific variance in sperm morphometry: a comparison between wild and domesticated Zebra FinchesTaeniopygia guttata

“…Also, importantly, this work validates the use of the domesticated Zebra Finch for further studies of post-copulatory sexual selection and sperm competition in the laboratory (e.g. Birkhead 2010, Forstmeier et al 2011, Tschirren et al 2012, where the amenability of the species to experimental research will continue to provide an excellent opportunity for intensive behavioural and physiological study.…”

“…The Zebra Finch is a classic avian study system for sexual selection and our results suggest that at least with respect to this character the domestication process has had no significant effect on the observed phenotypic variance (other characters such as ejaculate volume, sperm swimming speed and longevity remain to be studied). Birkhead 2010, Forstmeier et al 2011, Tschirren et al 2012, where the amenability of the species to experimental research will continue to provide an excellent opportunity for intensive behavioural and physiological study. Our findings are important because we have demonstrated that the rather unexpectedly high level of variance in sperm morphometry first described in a domestic population of Zebra Finches is not an artefact of captivity or the domestication process (Calhim et al 2007, Immler et al 2008, Kleven et al 2008.…”

“…Ward (1998) suggested that as in pre-copulatory female choice, in which individual females show variation in mate preferences, females might also exhibit preference for different sperm types (Ward 1998). However, the lack of a significant difference in sperm morphometry variance between wild and domesticated Zebra Finches is perhaps not surprising when considering the relatively low level of post-copulatory sexual selection present in natural populations of this species (extra-pair paternity rate < 2%; Birkhead et al 1990, Birkhead 2010. The only sperm trait for which we found a significant difference was sperm head length, and only one wild population showed a significant difference in this character.…”

“…The only sperm trait for which we found a significant difference was sperm head length, and only one wild population showed a significant difference in this character. However, the lack of a significant difference in sperm morphometry variance between wild and domesticated Zebra Finches is perhaps not surprising when considering the relatively low level of post-copulatory sexual selection present in natural populations of this species (extra-pair paternity rate < 2%; Birkhead et al 1990, Birkhead 2010. The relaxed selective pressure results in high variance in sperm morphometry, and therefore the removal of sperm competition as one selective pressure may have a relatively small impact.…”

The Zebra Finch: the ultimate Australian supermodel

“…Tim Birkhead, Nancy Burley, Nicky Clayton were all welcomed to join Richard in the field, where they gathered important data and developed a better understanding of the bird that they were studying in their far-off laboratories. Birkhead (2010) describes the personal generosity and enthusiasm that Richard afforded him and which was instrumental in accommodating his desires to begin his studies of the Zebra Finch. Over 20 years later, Richard's generosity remained the same, despite his frustrations at the lack of research support that he was able to attract.…”