Birkhead, T.R., Fletcher, F. and Pellatt, E.J. (1998) Testes asymmetry, condition and sexual selection in birds: an experimental test. Proceedings of the Royal Society Series B: Biological Sciences, 265 (1402). pp. 1185-1189. ISSN 1471-2954
The functional significance of the marked directional asymmetry in testes size observed in many bird species is obscure. Møller suggested that (i) the smaller of the two testes serves a compensatory role and increases in size (and hence reduces asymmetry) when the larger one is defective in some way, and (ii) as a consequence, the degree of directional asymmetry in testes size reflects male quality and covaries positively with the expression of secondary sexual traits.We conducted an experimental test of these two hypotheses in the zebra finch,Taeniopygia guttata. Neither hypothesis was supported. First, there was no significant relationship between the size of the left testis and relative testes asymmetry. Second, we obtained no support for the hypothesis that the degree of directional asymmetry in testes mass covaried with condition. On the contrary, directional asymmetry in testes mass was signifcantly greater in birds whose condition was experimentally reduced, compared with control birds. Moreover, we found no significant relationships between testes asymmetry and secondary sexual traits. We conclude that directional asymmetry in testes size does not reflect male condition in the zebra finch.
|Copyright, Publisher and Additional Information:||© 1998 The Royal Society|
|Institution:||The University of Sheffield|
|Academic Units:||The University of Sheffield > Faculty of Science (Sheffield) > School of Biological Sciences (Sheffield) > Department of Animal and Plant Sciences (Sheffield)|
|Depositing User:||Sherpa Assistant|
|Date Deposited:||01 Jul 2005|
|Last Modified:||07 Jun 2014 03:31|