Am Nat. 2021 Oct;198(4):489-505. doi: 10.1086/715745. Epub 2021 Aug 16.
AbstractVarious prey animals behave conspicuously to approaching predators. The conspicuous behavior is considered to be an antipredator signal, and the frequency of signaling individuals in a population differs between males and females in many species. We theoretically assessed the evolution of the inter- and intrasexual dimorphism in antipredator signaling by developing an evolutionary game model. We particularly focused on the Chinese grasshopper, , in which only a proportion of males and no females escape conspicuously. In our model, the antipredator signal was assumed to be costly and affect the probabilities of predation of both the signaling individual (individual effect) and the signaling or nonsignaling conspecifics around it (collective effect). The model indicates that (1) a positive individual effect is essential for the evolution of antipredator signaling; (2) sexual dimorphism in fecundity cost for signaling individuals or natural predation probability can produce intersexual dimorphism in the signaling where all individuals of one sex and no individuals of the other sex emit signal; and (3) a positive collective effect can explain the intrasexual dimorphism where only some individuals of one sex signal. This study provides the first model of intrasexual dimorphism in antipredator signaling and brings new testable predictions.
摘要 各种猎物动物在接近捕食者时会表现出明显的行为。这种明显的行为被认为是一种抗捕食者信号，在许多物种中，种群中发出信号的个体的频率在雄性和雌性之间存在差异。我们通过开发一个进化博弈模型，从理论上评估了抗捕食者信号的雌雄二型性的进化。我们特别关注中国草蜢， ，其中只有一部分雄性而没有雌性会明显地逃跑。在我们的模型中，抗捕食者信号被假设是有代价的，并影响信号个体（个体效应）和其周围的信号或非信号同种个体（集体效应）的被捕食概率。该模型表明：（1）个体效应为正对于抗捕食者信号的进化是必要的；（2）对发出信号的个体的繁殖代价或自然捕食概率的性二型性可以产生仅在一种性别的所有个体发出信号而另一种性别的个体不发出信号的两性二型性；（3）正的集体效应可以解释仅在一种性别的一些个体发出信号的种内两性二型性。本研究提供了抗捕食者信号的种内两性二型性的第一个模型，并带来了新的可测试的预测。
