Data from: Chemically-mediated sexual signals restrict hybrid speciation in a flea beetle

The evolution of reproductive isolation following hybridization is a major obstacle that may limit the prevalence of hybrid speciation among specific groups of organisms. Here we use a flea beetle system to offer a behavioral hypothesis for why there are so few examples of homoploid hybrid speciation among insects. Specifically, we examined cuticular hydrocarbon (CHC) mating signals and mate choice decisions of Altica fragariae and A. viridicyanea to test whether the signals produced by hybrids cause prezygotic reproductive isolation. Although hybrids of A. fragariae and A. viridicyanea had unique CHC profiles as compared to the parental species, mate choice trials indicated that these differences were insufficient to prevent gene flow between hybrids and parental species. We found that mate choice decisions and CHC signals were not correlated. Considering the ubiquity of CHC signaling molecules in insects, we propose that decoupling of CHC signals and mate choice may be a general mechanism limiting hybrid speciation in insects.杂交后生殖隔离的演化是可能限制特定类群生物中同倍体杂交物种形成（homoploid hybrid speciation）普遍性的主要障碍。本研究以跳甲实验体系为研究对象，针对昆虫中同倍体杂交物种形成案例稀少的原因提出一项行为学假说。具体而言，我们检测了草莓蚤跳甲（Altica fragariae）与绿圆跳甲（A. viridicyanea）的表皮碳氢化合物（cuticular hydrocarbon, CHC）交配信号以及配偶选择行为，以此检验杂交个体产生的信号是否会引发合子前生殖隔离（prezygotic reproductive isolation）。尽管草莓蚤跳甲与绿圆跳甲的杂交个体相较于亲本物种拥有独特的表皮碳氢化合物谱型，但配偶选择实验表明，这些差异不足以阻止杂交个体与亲本物种间的基因交流。我们发现配偶选择决策与表皮碳氢化合物信号之间并无关联。鉴于表皮碳氢化合物信号分子在昆虫中普遍存在，我们提出：表皮碳氢化合物信号与配偶选择的解耦，可能是限制昆虫杂交物种形成的一种普遍机制。