Pale by comparison: competitive interactions between signalling female glow-worms

When individuals differ in their abilities to compete for a mate, weaker competitors may evolve tactics to increase their mating success. Exploiting attractiveness of others to get mates is a common tactic in many taxa, although examples of this behavior in females are scarce. In glow-worms (Lampyris noctiluca L., Coleoptera: Lampyridae), females attract males by glowing and males prefer the brightest female. How unattractive females succeed in competition for mates is largely understudied. We hypothesize that less attractive female glow-worms may succeed in competition over mates by parasitizing glow of more attractive competitors. We tested our hypothesis with a combination of field and laboratory experiments. Contrary to our expectations, we found that females move away from brighter competitors. This behavior may explain our field observation that females are often more than one meter apart from each other. Increasing distance to a brighter female may make comparison on brightness d...

当个体在求偶竞争能力上存在差异时，竞争力较弱的个体可能会演化出策略以提升自身的交配成功率。利用其他个体的吸引力来获取配偶是诸多动物分类群中常见的策略，尽管雌性个体中该行为的实例较为罕见。在夜光虫（Lampyris noctiluca L., 鞘翅目：萤科）中，雌性通过发光吸引雄性，而雄性更偏好发光亮度更高的雌性。吸引力较低的雌性如何在求偶竞争中获得成功，目前尚未得到充分研究。我们提出假说：吸引力较弱的雌性夜光虫或许可通过寄生式利用更具吸引力的竞争者的发光信号，在求偶竞争中获得成功。我们结合野外实验与室内实验对该假说进行了验证。与我们的预期相反，我们观察到雌性夜光虫会远离发光更亮的同类竞争者。该行为或可解释我们的野外观测结果：雌性夜光虫之间的间距通常超过一米。与发光更亮的雌性个体拉开距离，可能会削弱亮度方面的比较……