Female cuticular hydrocarbons can signal indirect fecundity benefits in an insect

Male choosiness of prospective female mating partners provides an increasingly recognised pathway through which males can increase their fitness. For example, males may increase their number of offspring by targeting more fecund females as mating partners. If fecundity is heritable, males that mate with more fecund females can also receive the indirect benefit of more fecund daughters. In species where female fecundity is not directly assessable, female ornaments may act as signals of fecundity. However, whether female ornaments reliably signal the indirect benefit of more fecund daughters is not well understood. We investigated this question using the field cricket, Teleogryllus oceanicus. Previous work had identified the cuticular hydrocarbon (CHC) profile as a female sexual display trait in T. oceanicus. To examine whether CHCs can provide a reliable signal of fecundity, we tested whether individual CHC compounds and the first principal axis of CHC variation (PC1) are genetically correlated with ovary mass, a reliable proxy for fecundity in this species. We found significant genetic correlations between ovary mass and three individual CHC compounds, as well as PC1. This result indicates that by targeting females as mating partners based on their CHC profile, males can sire more fecund daughters.

雄性对潜在雌性交配对象的择偶偏好，是目前逐渐被学界认可的雄性提升自身适合度的重要途径。例如，雄性可通过选择繁殖力更强的雌性作为交配对象，以增加自身后代的数量。若繁殖力具有可遗传性，那么与高繁殖力雌性交配的雄性，还能获得间接收益：其后代中将出现繁殖力更强的雌性个体。对于无法直接评估雌性繁殖力的物种，雌性的装饰特征可作为繁殖力的信号。然而，目前学界对于雌性装饰特征能否可靠传递“产生更高繁殖力雌性后代”这一间接收益的信号，仍缺乏充分认知。本研究以大洋洲蝼蛄蟋蟀（Teleogryllus oceanicus）为研究对象，针对这一问题展开探究。已有研究表明，该物种雌性的表皮碳氢化合物（cuticular hydrocarbon, CHC）谱图属于雌性性展示性状。为探究表皮碳氢化合物能否作为繁殖力的可靠信号，本研究检验了单个表皮碳氢化合物组分以及表皮碳氢化合物变异的第一主成分（PC1）是否与卵巢质量存在遗传相关——而卵巢质量是该物种繁殖力的可靠替代指标。研究发现，卵巢质量与三种单个表皮碳氢化合物组分以及PC1均存在显著的遗传相关。这一结果表明，雄性若根据雌性的表皮碳氢化合物谱图选择交配对象，便可繁育出繁殖力更强的雌性后代。