Large males have fewer water mites (Arrenurus sp.) on the variable bluet (Coenagrion pulchellum) damselfly

Abstract

Ectoparasitic water mites of the genus Arrenurus Dugès, 1834 may affect damselflies in different ways, resulting in lower longevity and reproduction success. We studied the variation of water mite occurrence on the variable bluet (Coenagrion pulchellum (Vander Linden, 1823)) damselfly in relation to the host’s sex, location, and wing length, as well as the amount of black pigment on the abdomens of males. In our study, we found that water mite prevalence and abundance were higher on females. Location of the populations did not affect the prevalence of water mites, nor did the colouring of males. The prevalence and abundance of water mites was lower on larger males than on smaller ones. Our results suggest that females are likely to have more water mites due to different behaviour and life-history strategies. According to our results, male body size is a sign of good condition and, thus, of sufficient resources available to be directed to strengthening their immune systems.