Feldhaar Heike, Foitzik Susanne, Heinze Jürgen
Lehrstuhl für Verhaltensphysiologie und Soziobiologie Zoologie II, Universität Würzburg, Am Hubland, 97074 Würzburg, Germany.
Philos Trans R Soc Lond B Biol Sci. 2008 Sep 12;363(1505):2891-9. doi: 10.1098/rstb.2008.0022.
The extraordinary lifelong partner commitment in social insects is expected to increase choosiness in both sexes and therefore to be associated with particularly low hybridization frequencies. Yet, more and more studies reveal that in many ant taxa hybrids are surprisingly common, with up to half of all female sexuals receiving sperm from allospecific males in extreme cases. In a few ant species, hybridization has led to the evolution of reproductively isolated new lineages with a bizarre system of genetic caste differentiation: colonies produce hybrid workers and pure-lineage female sexuals. This requires that colonies either contain multiple queens or that queens mate multiple times. In most other cases, hybridization appears to be an evolutionary dead end and fertile hybrid queens are rarely found. In such cases, haplodiploid sex determination appears to decrease the costs of mating with an allospecific male. As long as hybrid workers are viable, a cross-mated queen can partially rescue its fitness by producing males from unfertilized eggs. Mating with an allospecific partner may thus be an option for queens when conspecific mates are not available. The morphological similarity of most ant males, perhaps resulting from the lack of sexual conflict, may similarly contribute to the commoness of hybridization.
社会昆虫终生伴侣关系的特殊性，预计会使两性在择偶时更加挑剔，因此杂交频率会特别低。然而，越来越多的研究表明，在许多蚂蚁类群中，杂交现象惊人地普遍，在极端情况下，高达一半的雌性有性生殖个体接受来自异种雄性的精子。在少数蚂蚁物种中，杂交导致了具有奇特遗传等级分化系统的生殖隔离新谱系的进化：蚁群会产生杂交工蚁和纯系雌性有性生殖个体。这就要求蚁群要么有多个蚁后，要么蚁后多次交配。在大多数其他情况下，杂交似乎是进化的死胡同，很少能发现可育的杂交蚁后。在这种情况下，单倍二倍体性别决定似乎降低了与异种雄性交配的成本。只要杂交工蚁能够存活，杂交交配的蚁后就可以通过产生未受精卵发育成的雄性来部分挽救其繁殖适应性。因此，当没有同种配偶时，与异种配偶交配可能是蚁后的一种选择。大多数蚂蚁雄性的形态相似，这可能是由于缺乏性冲突导致的，同样也可能导致杂交现象普遍存在。
