Data from: Speciation is not necessarily easier in species with sexually monomorphic mating signals

Should we have different expectations regarding the likelihood and pace of speciation by sexual selection when considering species with sexually monomorphic mating signals? Two conditions that can facilitate rapid species divergence are Felsenstein's one-allele mechanism and a genetic architecture that includes a genetic association between signal and preference loci. In sexually monomorphic species, the former can manifest in the form of mate choice based on phenotype matching. The latter can be promoted by selection acting upon genetic loci for divergent signals and preferences expressed simultaneously in each individual rather than separately, on signal loci in males and preference loci in females. Both sexes in the Chrysoperla carnea-group of green lacewings (Insecta, Neuroptera, Chrysopidae) produce sexually monomorphic species-specific mating signals. We hybridized the two species C. agilis and C. carnea to test for evidence of these speciation-facilitating conditions. Hybrid signals were more complex than the parents and we observed a dominant influence of C. carnea. We found a dominant influence of C. agilis on preferences in the form of hybrid discrimination against C. carnea. Preferences in hybrids followed patterns predicting preference loci that determine mate choice rather than a one-allele mechanism. The genetic association between signal and preference we detected in the segregating hybrid crosses indicate that speciation in these species with sexually monomorphic mating signals can have occurred rapidly. However, we need additional evidence to determine whether such genetic associations form more readily in sexually monomorphic species compared to dimorphic species and consequently facilitate speciation.在研究具有性单态交配信号的物种时，我们是否应当对性选择介导的物种形成的可能性与速率抱有差异化预期？能够促进物种快速分化的两类核心条件分别为费尔森斯坦单等位基因机制（Felsenstein's one-allele mechanism），以及包含信号位点与偏好位点间遗传关联的遗传架构（genetic architecture）。在性单态物种中，前者可表现为基于表型匹配的配偶选择行为；后者则可通过作用于在每个个体中同时表达、而非分别在雄性信号位点与雌性偏好位点上发挥功能的趋异信号与偏好遗传位点的选择作用得以强化。 隶属于昆虫纲（Insecta）、脉翅目（Neuroptera）、草蛉科（Chrysopidae）的绿草蛉卡纳组（Chrysoperla carnea-group）类群，其雌雄两性均会产生具有物种特异性的性单态交配信号。本研究通过杂交敏捷草蛉（Chrysoperla agilis, C. agilis）与普通草蛉（Chrysoperla carnea, C. carnea），对上述两类促进物种形成的条件开展验证实验。杂交后代的交配信号相较于亲本更为复杂，且我们观察到普通草蛉（C. carnea）对信号表型具有显性影响。同时我们发现，敏捷草蛉（C. agilis）对配偶偏好具有显性影响，具体表现为杂交个体对普通草蛉存在识别排斥行为。杂交个体的配偶偏好模式符合决定配偶选择的偏好位点的预测规律，而非费尔森斯坦单等位基因机制所预期的结果。 我们在分离杂交后代中检测到的信号与偏好之间的遗传关联表明，这类具有性单态交配信号的物种种化过程可能快速发生。然而，我们仍需更多实验证据来确定，相较于性二态物种，这类信号-偏好遗传关联在性单态物种中是否更易形成，进而是否能够进一步推动物种形成进程。