Terminal investment in multiple sexual signals: immune-challenged males produce more attractive pheromones

摘要: Summary 1. Trade-offs between current and future resource allocation can select for elevated reproductive effort in individuals facing mortality. Males are predicted to benefit from increasing investment costly sexually selected signals after experiencing an acute life span reduction, although few examples of such facultative terminal known. 2. In the mealworm beetle, Tenebrio molitor, males’ odours become more attractive females following a life-threatening immune challenge. However, pheromones involved unknown, hindering further insight into proximate mechanisms ultimate consequences investment. 3. Using chemical behavioural analyses, we show that cuticular hydrocarbons (CHCs) T. molitor dimorphic used by locate males. Moreover, both male CHCs glandular were affected experimental challenge fashion made them females. 4. The results suggest males terminally invest short- medium-range when they perceive reduced survival. constitutive inducible aspects female CHC production consistent with sex-specific selection on signalling defensive functions CHCs. The implications ‘dishonest’ efficacy sexual discussed.