Collaborative Research: Evolutionary Transition from Solitary to Gregarious Development in Parasitoid Wasps

合作研究：寄生蜂从独居到群居的进化转变。摘要：卵数的研究是行为生态学和生活史理论中最古老、最有成果的领域之一。一个中心主题是父母和后代之间在有限资源的分配和最优卵群数量上的冲突。寄生蜂（拟寄生蜂）一直是研究窝大小的首选生物，因为它们的宿主代表了后代发育的明确资源。如果每个寄主只有一个幼虫完成发育，则寄生蜂被分类为独居，如果每个寄主有一个以上的非寄生蜂后代发育，则寄生蜂被分类为群居。系统发育模式表明，群居性的进化源自于独居性的进化，而这种进化已经发生了很多次。种群遗传模型表明，有利于非亲杀行为传播的条件是严格的，但如果出现以下一个或多个因素，则可能会放宽：亲缘关系中性别分配行为的增加、幼虫流动性的丧失、获得区分亲缘关系和非亲缘关系的能力、近亲繁殖或超寄生现象的减少。虽然大多数拟寄生物类群的系统发育关系尚不清楚，但对Cotesia属的系统发育进行了充分研究，可以详细研究上述因素是否与该属的群居性进化有关。从其他Cotesia物种收集DNA序列将进一步加强系统发育。行为学研究将评估在群居性进化过程中亲性、流动性、性别分配和亲缘歧视的作用。野外和实验室研究将确定近亲繁殖和超寄生对群居性进化的影响。

Collaborative Research: The evolutionary transition from solitary to gregarious development in parasitoid wasps. Paul Ode1, James Whitfield2, and George Heimpel31North Dakota State University2University of Illinois at Urbana-Champaign3University of Minnesota-Twin CitiesAbstract:The study of clutch size is one of the oldest and most productive fields in behavioral ecology and life history theory. A central theme is the conflict between parents and offspring over the allocation of limiting resources and optimal clutch size. Parasitic wasps (parasitoids) have been favored organisms for clutch size studies because their hosts represent well-defined resources on which offspring develop. Parasitoids are classified as solitary if only one, typically siblicidal, larva completes development per host or gregarious if more than one non-siblicidal offspring develops per host. Phylogenetic patterns suggest that solitary development is ancestral to gregariousness and that this transition has occurred many times. Population genetic models suggest the conditions favoring the spread of non-siblicidal behavior are stringent but may be relaxed if one or more of the following factors occur: sex allocation behaviors increase within brood relatedness, loss of larval mobility, acquisition of the ability to distinguish relatives from non-relatives, inbreeding, or reduced superparasitism. While the phylogenetic relationships of most parasitoid taxa are not well understood, the well-studied phylogeny of the braconid genus Cotesia allows detailed study of whether the aforementioned factors were associated with the evolution of gregariousness within this genus. Collection of DNA sequences from additional Cotesia species will further strengthen the phylogeny. Behavioral studies will assess the role of siblicide, mobility, sex allocation, and kin-discrimination in the evolution of gregariousness. Field and laboratory studies will determine the effects of inbreeding and superparasitism on the evolution of gregariousness.