Older males are not only attractive to but also aggressive toward females in Gnatocerus cornutus

In theory, a male should change the allocation of fighting and mating efforts in relation to his age. Thus, the consequences of sexual selection may be complicated by changes in the male resource allocation due to aging. However, previous studies have focused on changes in female mate choice and male-male competition with aging separately, and the impact of aging on the relationship between mate choice and male competition is unknown. Here, we examined how male competitiveness and attractiveness and their relationship changes over male lifespan in Gnatocerus cornutus. In this species, males perform courtship displays and fight rival males for mates. Older males are more competitive in male fighting and aggressive toward females than younger males. The aggression is also directed toward females. Almost all older males who attacked a female failed to copulate, while younger males never attacked the females. As a result, copulation success decreased with age. When an older male did not mis...从理论上来说，雄性个体应当依据自身年龄调整争斗与交配的资源投入分配。因此，衰老引发的雄性资源分配改变，可能会使性选择的演化效应变得更为复杂。然而，既往研究多分别聚焦于衰老对雌性择偶偏好与雄性间竞争的影响，而衰老对择偶偏好与雄性竞争之间关系的作用仍不明确。本研究以角胸郭公虫（Gnatocerus cornutus）为实验对象，探究了雄性竞争力、吸引力及其二者间的关联随雄性寿命周期的变化规律。该物种的雄性会通过求偶展示吸引配偶，并与同性竞争者争斗以获取交配机会。相较于年轻雄性，年长雄性在雄性争斗中更具竞争力，且对雌性的攻击性更强。此类攻击性同样会指向雌性个体。几乎所有攻击过雌性的年长雄性都未能成功完成交配，而年轻雄性从未对雌性发起攻击。因此，交配成功率随雄性年龄增长而下降。当年长雄性未发生……