دانلود گزارش کارورزی و کار آموزی

چکیده : 

Traits subject to ecologically based divergent selection that also affect nonrandom mating (i.e. ‘magic

traits’) may hasten incipient speciation. In this study, we investigated whether nonrandom mating results

from ecological divergence between swamp sparrow, Melospiza georgiana, subspecies. As a byproduct

of adaptive divergence in bill morphology between populations of swamp sparrows, there is a

corresponding divergence in features of song shown to be salient to females, potentially providing a

mechanism of reproductive isolation. Thus, female mating preferences for song could result in prezygotic

isolation that prevents gene flow between subspecies. In this study we tested the hypothesis that female

preferences for song provide a mechanism of reproductive isolation that limits gene flow between

subspecies. Using copulation solicitation assays, we found that female coastal plain swamp sparrows

showed a significant preference for consubspecific songs over heterosubspecific songs.We further tested

whether mating preferences in coastal populations explain observed differences in song between subspecies.

We found evidence that mating preferences in coastal females may explain the evolution of

some acoustic features of song. We suggest that the bill may be an example of a ‘magic trait’ that

contributes to continued divergence of swamp sparrow subspecies