Sexual signals reveal males’ oxidative stress defenses: testing the hypothesis in an invertebrate

1.The hypothesis that sexual traits reveal the oxidative stress resistance of their bearers has been widely tested in vertebrates but remains unexplored in invertebrates. Here, Hetaerina americana was used to test whether oxidative stress defenses are advertised by male wing spot size and color (a male sexual trait). To this end we asked (1) whether oxidative stress reduced survival, (2) whether wing spot size revealed males’ antioxidant defenses, and (3) how wing spot size and color were affected by oxidative stress.

2.We elevated oxidative stress by injecting adult males with paraquat (a compound that favors the production of free radicals) and then examined how this affected male survival and wing spot size. We then related the expression of wing spot size to indicators of oxidative stress – H2O2 and total Antioxidant Capacity (TAC), Super Oxide Dismutase (SOD) and Catalase (CAT) – in adult males (whose wing spot is fixed) injected with Paraquat (PQ). In teneral males, whose wing-...