Carson Hampton L
Department of Genetics, University of Hawaii, Honolulu, HI, 96822.
Evolution. 1985 May;39(3):678-686. doi: 10.1111/j.1558-5646.1985.tb00404.x.
The large Drosophila species of Hawaii display sexual dimorphism and elaborate species-specific courtship patterns. Male characters related to courtship attract particular attention since they frequently constitute the most conspicuous taxonomic differences between Hawaiian species. The present study concerns intraspecific genetic variation in a courtship-related male character. D. silvestris, endemic to the geologically new volcanoes of Hawaii island, displays a brush of large dorsal cilia on the tibia of the foreleg of the male fly. This is used to stimulate the female during courtship. Genetic variation between local populations has previously been shown to exist for both sexual behavior and cilia number. The present paper reports the results of a study of cilia number variation in males collected at a single site over the period 1976-1980. Male progeny of females captured in nature were also studied. The mean number of cilia in the natural population was stable except for 1979 when it rose significantly, falling back again in 1980. The data indicate the existence of ample genetic variance for this character, existing as a balanced polymorphism in the natural population. The character appears to be under stabilizing selection. It is hypothesized that sexual selection is a contributing factor.
夏威夷的大型果蝇物种表现出性别二态性以及复杂的物种特异性求偶模式。与求偶相关的雄性特征格外引人注目，因为它们常常构成夏威夷物种之间最显著的分类差异。本研究关注与求偶相关的雄性特征的种内遗传变异。夏威夷岛地质上新形成的火山所特有的拟果蝇，雄性果蝇前腿胫节上有一排大型背侧纤毛。在求偶过程中，这些纤毛用于刺激雌性。此前已表明，当地种群之间在性行为和纤毛数量方面均存在遗传变异。本文报告了1976年至1980年期间在单一地点采集的雄性果蝇纤毛数量变异的研究结果。对在自然环境中捕获的雌性果蝇的雄性后代也进行了研究。除了1979年纤毛平均数显著上升，1980年又回落之外，自然种群中纤毛的平均数是稳定的。数据表明该特征存在充足的遗传变异，在自然种群中以平衡多态性的形式存在。该特征似乎受到稳定选择。据推测，性选择是一个促成因素。
