High-quality male field crickets invest heavily in sexual display but die young

Only high-quality males can bear the costs of an extreme sexual display(1-4). As a consequence, such males are not only more attractive, but they often live longer than average(5). Recent theory predicts, however, that high-quality males should sometimes invest so heavily in sexual displays that they die sooner than lower quality males(2,6-9). We manipulated the phenotypic quality of field crickets, Teleogryllus commodus, by altering the protein content of their diet. Here we show that nymphs and adult females reared on a high-protein diet lived longer than those on a low-protein diet. In contrast, adult males reared on a high-protein diet died sooner than those on low-protein diets because they invested more energy in calling during early adulthood. Our findings uphold the theoretical prediction that the relationship between longevity and sexual advertisement may be dynamic(2,3,6-8) (that is, either positive or negative), depending on local conditions(3,6) such as resource availability. Moreover, they caution the use of longevity as a proxy for fitness in sexual selection studies, and suggest avenues for future research on the relationship between sexual attractiveness and ageing.