Data from: Use of an exotic host plant affects mate choice in an insect herbivore

The colonization of exotic plants by herbivorous insects has provided opportunities for investigating causes and consequences associated with the evolution of niche breadth. The butterfly Lycaeides melissa utilizes exotic alfalfa, Medicago sativa, which is a relatively poor larval resource, and previous studies have found that caterpillars that consume M. sativa develop into smaller and less fecund adults. Here we investigate the effect of smaller female body size on male mate preference, a previously unexplored consequence of novel host use. Smaller females, which developed on the exotic host, were less likely to be visited by males. This result was confirmed with a second set of choice tests involving females reared on a single plant species, thus ruling out host-specific confounding factors. We suggest that an effect on mate choice be considered as part of the complex suite of factors determining persistence of herbivorous insects following colonization of new habitats or resources.植食性昆虫入侵外来植物的研究体系，为探究生态位宽度（niche breadth）演化的相关成因与后果提供了重要契机。梅利莎蓝灰蝶（Lycaeides melissa）可取食外来植物紫花苜蓿（Medicago sativa），但该寄主属于相对劣质的幼虫营养资源。既往研究表明，取食紫花苜蓿的幼虫发育至成虫后，体型更小且繁殖力更弱。本研究聚焦于雌虫体型偏小对雄虫配偶选择偏好的影响——这是新型寄主利用行为此前未被探明的一项后果。实验结果显示，在异种寄主上发育的小型雌虫，被雄虫访寻的概率显著更低。我们通过第二组仅以单一寄主植物饲养雌虫的选择试验验证了该结果，由此排除了寄主特异性混淆因素的干扰。我们提出，在探究植食性昆虫入侵新栖息地或利用新资源后的种群存续相关的复杂影响因子时，应将其对配偶选择的影响纳入考量范畴。