Symonds Matthew R E, Elgar Mark A
Centre for Integrative Ecology, School of Life and Environmental Sciences, Deakin University, Burwood, Victoria, Australia ; Department of Zoology, University of Melbourne, Melbourne, Victoria, Australia.
PLoS One. 2013 Oct 14;8(10):e78297. doi: 10.1371/journal.pone.0078297. eCollection 2013.
Chalcidoid wasps represent one of the most speciose superfamilies of animals known, with ca. 23,000 species described of which many are parasitoids. They are extremely diverse in body size, morphology and, among the parasitoids, insect hosts. Parasitic chalcidoids utilise a range of behavioural adaptations to facilitate exploitation of their diverse insect hosts, but how host use might influence the evolution of body size and morphology is not known in this group. We used a phylogenetic comparative analysis of 126 chalcidoid species to examine whether body size and antennal size showed evolutionary correlations with aspects of host use, including host breadth (specificity), host identity (orders of insects parasitized) and number of plant associates. Both morphological features and identity of exploited host orders show strong phylogenetic signal, but host breadth does not. Larger body size in these wasps was weakly associated with few plant genera, and with more specialised host use, and chalcidoid wasps that parasitize coleopteran hosts tend to be larger. Intriguingly, chalcidoid wasps that parasitize hemipteran hosts are both smaller in size in the case of those parasitizing the suborder Sternorrhyncha and have relatively larger antennae, particularly in those that parasitize other hemipteran suborders. These results suggest there are adaptations in chalcidoid wasps that are specifically associated with host detection and exploitation.
小蜂是已知动物中种类最为丰富的超科之一，已描述的种类约有23,000种，其中许多是寄生性昆虫。它们在体型、形态以及寄生性昆虫的寄主种类方面极为多样。寄生性小蜂利用一系列行为适应性来便于对其多样的昆虫寄主进行利用，但寄主利用如何影响体型和形态的进化在该类群中尚不清楚。我们对126种小蜂进行了系统发育比较分析，以检验体型和触角大小是否与寄主利用的各个方面存在进化相关性，包括寄主广度（专一性）、寄主身份（被寄生昆虫的目）以及植物关联数量。形态特征和被利用寄主目的身份均显示出强烈的系统发育信号，但寄主广度则不然。这些黄蜂体型较大与较少的植物属相关，且与更专一的寄主利用相关，寄生鞘翅目寄主的小蜂往往体型更大。有趣的是，寄生半翅目寄主的小蜂，在寄生粉虱亚目的情况下体型较小，而触角相对较大，特别是在寄生其他半翅目亚目的小蜂中。这些结果表明，小蜂存在与寄主检测和利用特别相关的适应性。
