Castrezana Sergio J, Markow Therese Ann
Department of Ecology and Evolutionary Biology, University of Arizona, Tucson, AZ 85721, USA.
Behav Genet. 2008 Jul;38(4):437-45. doi: 10.1007/s10519-008-9209-0. Epub 2008 Jun 17.
Drosophila mettleri is found in deserts of North America breeding in soil soaked by the juices of necrotic cacti. Saguaro (Carnegiea gigantea) and cardón (Pachycereus pringlei) are the usual host cacti in Mexico and Arizona, while prickly pear (Opuntia spp.) is used by an isolated population on Santa Catalina Island off the southern California Coast. Populations of D. mettleri show significant local genetic differentiation, especially when geographical isolation is coupled with host shifts. We tested for evidence of sexual isolation among allopatric populations of D. mettleri using a variety of choice and no-choice tests. Populations exhibited significant differences in mating propensity, which translated into significant deviations from random mating. While in some cases these deviations were consistent with sexual isolation, in others, negative assortative mating was observed. No relationship between degree of genetic differentiation and the appearance of sexual isolation was detected.
梅氏果蝇分布于北美沙漠地区,在被坏死仙人掌汁液浸湿的土壤中繁殖。树形仙人掌(巨人柱)和仙人掌(皮氏仙人掌)是墨西哥和亚利桑那州常见的寄主仙人掌,而南加州海岸外圣卡塔利娜岛上的一个孤立种群则以仙人掌属植物为食。梅氏果蝇种群表现出显著的局部遗传分化,尤其是当地理隔离与寄主转移同时发生时。我们使用多种选择和无选择试验,测试了梅氏果蝇异地种群间性隔离的证据。不同种群在交配倾向方面存在显著差异,这导致了与随机交配的显著偏差。虽然在某些情况下,这些偏差与性隔离一致,但在其他情况下,观察到了负选型交配。未检测到遗传分化程度与性隔离出现之间的关系。