Abstract
Sexual adornments often vary markedly across a species' range, which presumably is owing to differences in local environmental conditions and the associated selection pressures, such as natural versus sexual selection or the relative signaling value of different ornamental traits. However, there are only a few reported examples in which the information content of mating signals varies geographically, and even fewer in which a set of secondary sexual traits serves different signaling functions in different populations. Classic studies of sexual selection in the European barn swallow (Hirundo rustica rustica) demonstrate that elongate tail-streamers provide several reproductive advantages to males and females and are used as reliable signals of mate quality. Here, we show that tail-streamers do not appear to confer these same benefits in a population of barn swallows from North America (Hirundo rustica erythrogaster). Instead, ventral plumage coloration, which is more exaggerated in North American swallows compared with their European counterparts, predicts patterns of assortative mating and annual reproductive success in H. r. erythrogaster. These observations support the idea that ornamental traits can serve different functions among animal populations and suggest that geographic variation in different sexual signals may facilitate population divergence, which may ultimately lead to speciation.
Original language | English (US) |
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Pages (from-to) | 455-461 |
Number of pages | 7 |
Journal | Behavioral Ecology |
Volume | 15 |
Issue number | 3 |
DOIs | |
State | Published - May 2004 |
Externally published | Yes |
Keywords
- Geographic variation
- Hirundo rustica
- Population divergence
- Sexual selection
- Sexual signals
ASJC Scopus subject areas
- Ecology, Evolution, Behavior and Systematics
- Animal Science and Zoology