Sexual attractiveness and reproductive performance in ageing females of a coccoid insect

Abstract

Female age strongly influences reproductive success in various animals. Males are, therefore, expected to show preferential responses to sexual signals released from females of ages suitable for reproduction. Here, however, we report an unexpected and contradictory effect of ageing on sexual attractiveness and reproductive performance in a coccoid insect: the pheromone-based attractiveness of females increased with ageing, though their reproductive performance was in rapid decline. Surprisingly, senescent females continued releasing relatively high amounts of pheromone and maintained their sexual attractiveness, even at ages when they had almost completely lost fertility, with reduced densities of endosymbionts to support their physiology. Our dataset suggests a potential sexual conflict within a pheromone communication system, where females benefit at males' expense through deceptive signals of fertility.