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

Abstract

Only high-quality males can bear the costs of an extreme sexual display^1,2,3,4. As a consequence, such males are not only more attractive, but they often live longer than average⁵. Recent theory predicts, however, that high-quality males should sometimes invest so heavily in sexual displays that they die sooner than lower quality males^2,6,7,8,9. 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^2,3,6,7,8 (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.