Møller A P, Cuervo J J
Laboratoire d'Ecologie, CNRS URA 258, Université Pierre et Marie Curie, Bât. A, 7ème étage, 7 quai St. Bernard, Case 237, F-75252 Paris Cedex 5, France.
Estación Biológica de Doñana, Pabellón del Peru, Avda. de María Luisa s/n, E-41013, Sevilla, Spain.
Evolution. 1998 Jun;52(3):859-869. doi: 10.1111/j.1558-5646.1998.tb03710.x.
The hypothesis that sexual selection promotes speciation has rarely been tested. We identified 70 evolutionarily independent events of feather ornaments in birds. For each focal species we noted the number of ornamented and nonornamented species belonging to its genus and its number of subspecies, as well as its mating system and the extent of its geographic range. For purposes of comparison, we randomly chose a second, nonornamented species for which we obtained information on the number of subspecies, and in cases in which the nonornamented species was in the same genus, we chose a third, nonornamented species in a related genus and obtained the same information. We then noted the number of species in each genus and the difference in numbers of species, or species richness, between paired genera. For the genera of the focal ornamented species, we regressed number of ornamented species on number of nonornamented species and found a positive relationship. As number of species per genus rose, number of ornamented species per genus rose more rapidly, indicating that more speciose genera have a higher proportion of ornamented species than less speciose genera. We then took the deviations from this regression, the residual number of species, and regressed them on the differences in species richness between the paired genera. This relationship was positive indicating that ornamented genera with more than the expected number of ornamented species were more speciose with respect to their paired genera than were genera with fewer than the expected number of ornamented species. Finally, we compared the deviations from this regression, the residual number of ornamented species, with species' mating system and found a greater residual number of ornamented species among species whose mating system is associated with greater skew in male mating success and thus more intense sexual selection. Ornamented species had more subspecies than nonornamented species, even when controlling for geographic range, suggesting an association between subspeciation and ornaments.
性选择促进物种形成这一假说很少得到验证。我们识别出鸟类羽毛装饰的70个进化上独立的事件。对于每个重点物种，我们记录了其所属属中具装饰性和不具装饰性的物种数量及其亚种数量，以及其交配系统和地理分布范围。为了进行比较，我们随机选择了第二个不具装饰性的物种，并获取了其亚种数量的信息，若该不具装饰性的物种与重点物种同属，我们则在相关属中选择第三个不具装饰性的物种并获取相同信息。然后我们记录了每个属中的物种数量以及配对属之间物种数量或物种丰富度的差异。对于重点具装饰性物种的属，我们将具装饰性物种的数量对不具装饰性物种的数量进行回归分析，发现存在正相关关系。随着每个属中物种数量的增加，每个属中具装饰性物种的数量增长得更快，这表明物种较多的属比物种较少的属具装饰性物种的比例更高。然后我们取该回归的偏差，即物种的剩余数量，并将其对配对属之间的物种丰富度差异进行回归分析。这种关系是正相关的，表明具装饰性物种数量超过预期的属相对于其配对属而言比具装饰性物种数量少于预期的属物种更丰富。最后，我们将该回归的偏差，即具装饰性物种的剩余数量，与物种的交配系统进行比较，发现在交配系统与雄性交配成功率偏差更大且因此性选择更强烈的物种中，具装饰性物种的剩余数量更多。具装饰性物种比不具装饰性物种有更多的亚种，即使在控制地理分布范围的情况下也是如此，这表明亚种形成与装饰之间存在关联。
