Kukuk Penelope F, May Bernie
Department of Entomology, Cornell University, Ithaca, NY, 14853, USA.
Department of Natural Resources and Cornell Laboratory for Ecological and Evolutionary Genetics, Cornell University, Ithaca, NY, 14853, USA.
Evolution. 1990 Sep;44(6):1522-1528. doi: 10.1111/j.1558-5646.1990.tb03843.x.
Hymenoptera are characterized by a haplo-diploid mechanism of sex determination. Females are diploid and males are haploid. However, in many species diploid males may occur if individuals are homozygous at a sex determining locus. Diploid males were found in three out of four populations (nest aggregations) of the primitively eusocial, halictine bee Lasioglossum zephyrum for which samples of males were examined electrophoretically. The frequency of diploid males was greater in a small, geographically isolated population (the "Robinson" nest aggregation) than in a large population that had nearby neighboring populations (the "Salmon Creek A" nest aggregation). In addition, the proportion of polymorphic loci was lower in the Robinson nest aggregation suggesting that a bottleneck event or loss of alleles due to small population size occurred in the Robinson population that involved a loss in the number of alleles at the sex determining locus.
膜翅目昆虫的性别决定机制为单倍体 - 二倍体机制。雌性为二倍体，雄性为单倍体。然而，在许多物种中，如果个体在性别决定位点是纯合的，就可能出现二倍体雄性。在对雄性样本进行电泳检测的四个原始群居、隧蜂科蜜蜂淡翅切叶蜂的种群（巢穴聚集群体）中，有三个种群发现了二倍体雄性。在一个地理上孤立的小种群（“罗宾逊”巢穴聚集群体）中，二倍体雄性的频率高于一个有邻近种群的大种群（“鲑鱼溪A”巢穴聚集群体）。此外，罗宾逊巢穴聚集群体中多态位点的比例较低，这表明罗宾逊种群发生了瓶颈事件或因种群规模小导致等位基因丢失，其中涉及性别决定位点上等位基因数量的减少。
