Nonacs Peter, Tobin John E
Museum of Comparative Zoology, Harvard University, Cambridge, MA, 02138, USA.
Evolution. 1992 Dec;46(6):1605-1620. doi: 10.1111/j.1558-5646.1992.tb01157.x.
Queens of hymenopteran social parasites manipulate the workers of other social species into raising their offspring. However, nonconspecific brood care may also allow the parasite larvae to control their own development to a greater extent than possible in nonparasitic species. An evolutionary consequence of this may be the loss of the parasite's worker caste if the larvae can increase their fitness by developing into sexuals rather than workers. We argue that this loss is particularly likely in species in which there is little inclusive fitness benefit in working. Retention of a worker caste correlates with characteristics that increase the fitness of working relative to becoming a sexual, such as worker-production of males, high intracolony relatedness, and seasonal environments where the hosts of potential parasite queens are not always available. Further evidence strongly suggests that when the worker caste is evolutionarily lost in perennial species like ants, it disappears rapidly and through a reduction in caste threshold and queen size, so that parasite larvae become queens with less food than required to produce host workers. This evolutionary process, however, appears to lower overall population fitness, resulting in workerless parasite species having small populations and being geographically restricted. Conversely, in annual species like bees and wasps, workerless social parasitism evolves with no size reduction in queens, which is consistent with an expected lower level of queen/offspring conflict.
膜翅目社会性寄生昆虫的蚁后会操纵其他社会性物种的工蚁来抚养它们的后代。然而，异源抚育也可能使寄生幼虫比非寄生物种在更大程度上控制自身发育。如果幼虫通过发育成性蚁而非工蚁能够提高自身适应性，那么这可能会导致寄生昆虫的工蚁等级消失。我们认为，在工作中几乎没有广义适应性益处的物种中，这种等级消失的可能性尤其大。保留工蚁等级与一些特征相关，这些特征会增加工作相对于成为性蚁的适应性，比如工蚁产雄、群体内亲缘关系高以及潜在寄生蚁后的宿主并非随时都有的季节性环境。进一步的证据有力地表明，当像蚂蚁这样的多年生物种在进化过程中失去工蚁等级时，它会迅速消失，且通过降低等级门槛和蚁后体型来实现，这样寄生幼虫成为蚁后所需的食物比产生宿主工蚁所需的食物更少。然而，这个进化过程似乎会降低总体种群适应性，导致无工蚁的寄生物种数量少且分布地域受限。相反，在像蜜蜂和黄蜂这样的一年生物种中，无工蚁的社会性寄生现象在蚁后体型不减小的情况下进化，这与预期的较低水平的蚁后/后代冲突相一致。
