Survival after experimental manipulation in the territorial damselfly Hetaerina titia (Odonata: Calopterygidae): more ornamented males are not more pathogen resistant

It has been hypothesized that sexual ornaments communicate pathogen resistance ability. We experimentally explored the relationship between the expression of a male ornamental trait (wing pigmentation) of the damselfly Hetaerina titia and survival after a bacterial challenge. We infected males with Serratia marcescens (a Gram-negative bacteria typical of insects) and compared survival against a group infected with dead bacteria and a noninfected group. Wing pigmentation was entered as a predictor of survival in this comparison. Our study indicated that wing pigmentation was not a good predictor of immune ability against bacteria. This result contradicts previous findings in the same and other calopterygid species in which wing pigmentation intensity inversely correlated with gregarine infection levels. It also contradicts the general idea that ornaments are honest indicators of pathogen defense.