Mate guarding and the acquisition of new mates in Calopteryx maculata (P. de Beauvois) (Zygoptera: Calopterygidae)

The occurrence of guarding of non-mates by males of C. maculata appears to be a function of population density. Males in a high density Canadian population regularly defend females with whom they have not copulated, unlike males in a low density Virginian population (cf. J. ALCOCK, 1979, J. nut. Hist. 13: 439-446). But males in Canadian and other high density populations that are guarding mates (and non-mates) do occasionally respond sexually to new arrivals on their territories whereas repeat matings between a male and a recent partner are very rare. Both males and females apparently change their receptivity in response to several factors producing a variety of possible interactions between a territory owner and an arriving female. The interchange of signals between a pair leads males to copulate primarily with new partners.