Møller A P, Sorci G, Erritzøe J
Laboratoire d'Ecologie, CNRS URA 258, Université Pierre et Marie Curie, Bât. A, 7ème étage, F-75252 Paris Cedex 05, France.
Am Nat. 1998 Oct;152(4):605-19. doi: 10.1086/286193.
Sex differences in parasitism are common and may depend on sex differences in intensity of sexual competition, immunosuppression, or exposure to parasites. We used a large data set on the mass of two immune defense organs in birds (the bursa of Fabricius and the spleen) to test for consistent sex differences in immune defense. Males had a relative spleen mass that was consistently smaller, but more variable, than that of females across species of birds. A sex difference in the size of the spleen was not present among juveniles but was large and statistically significant among adults. The suppression of spleen mass in adult males increased with a measure of intensity of sexual selection: the frequency of extra-pair paternity. These findings suggest that sex differences in parasitism may arise as a consequence of sex differences in immune function, as mediated by sexual selection.
寄生现象中的性别差异很常见，可能取决于性竞争强度、免疫抑制或接触寄生虫方面的性别差异。我们使用了一个关于鸟类两个免疫防御器官（法氏囊和脾脏）质量的大型数据集，来测试免疫防御中是否存在一致的性别差异。在鸟类的各个物种中，雄性的相对脾脏质量始终比雌性小，但变化更大。脾脏大小的性别差异在幼鸟中不存在，但在成年鸟中很大且具有统计学意义。成年雄性脾脏质量的抑制随着性选择强度的一个指标——婚外父权频率的增加而增加。这些发现表明，寄生现象中的性别差异可能是由性选择介导的免疫功能性别差异导致的。
