Dominance-related seasonal song production is unrelated to circulating testosterone in a subtropical songbirdYork, J. E., Radford, A. N., de Vries, B., Groothuis, T. G. & Young, A. J., 1-Jul-2016, In : General and Comparative Endocrinology. 233, p. 43-52 10 p.
Research output: Contribution to journal › Article › Academic › peer-review
Circulating testosterone (T) is widely considered to play a key role in the production of sexual displays by male vertebrates. While numerous studies support a role for circulating T in promoting the production of song in male birds, this understanding is based primarily on evidence from seasonally breeding northern temperate species, leaving it unclear whether this mechanism generalizes to other regions of the world. Here we investigate whether variation in circulating levels of T can explain the marked within- and among-individual variation in male song performance observed in a subtropical population of the year-round territorial white-browed sparrow weaver (Plocepasser mahali mahali). Our findings reveal that both circulating T and male song production peaked at a similar time point, halfway through the population-level breeding season. However, while dominant males were more likely to sing and sang for longer than subordinate males, within-group paired comparisons revealed no dominance-related differences in circulating T. Moreover, comparisons both among and within individual dominant males revealed that song duration, syllable rate and proportion of time spent singing were all unrelated to circulating T. Together, our findings suggest that natural variation in male song production, at least in this population of white-browed sparrow weavers, is achieved principally through mechanisms other than variation in circulating T concentration. More widely, our results are in line with the view that male song production is not exclusively regulated by gonadally synthesized steroids.
|Number of pages||10|
|Journal||General and Comparative Endocrinology|
|Publication status||Published - 1-Jul-2016|
- Tropical endocrinology, Sexual signalling, Circulating testosterone, Seasonality, Dominance, MALE GREAT TITS, MALE EUROPEAN STARLINGS, ROWED SPARROW WEAVER, MALE BLUE TITS, COOPERATIVELY BREEDING SONGBIRD, COMMON-GARDEN EXPERIMENT, MALE BARN SWALLOWS, PLASMA TESTOSTERONE, TROPICAL BIRDS, TERRITORIAL AGGRESSION