MULTIPLE MATING IN CALOPTERYX MACULATA (ODONATA, CALOPTERYGIDAE) AND THE ADVANTAGE OF NON-CONTACT GUARDING BY MALES

Both males and females in a population of Calopteryx maculata mated more than once in the course of a single afternoon. The possibility that females might mate with an intruder or with a neighbouring territory owner may have favoured the evolution of guarding behaviour by males. Territorial males employed non-contact guarding of their mates. They perched on vegetation overlooking the oviposition site and repelled intruder males from the area. Territory owners were able to discriminate between females they had already mated and new arrivals. When previous mates left the oviposition site temporarily they usually were readmitted promptly by the resident male when they returned. New arrivals were usually courted, pursued and sometimes successfully mated, even if this meant briefly leaving an ovipositing mate unguarded in the territory. Non-contact guarding is interpreted as an adaptation to permit a territorial male to acquire new mates even while guarding previous ones. Comparisons with other odonates and a bee are presented in support of the hypothesis that non-contact guarding evolves when receptive females are relatively abundant and multiple mating by some males a regular possibility. When receptive females are consistently scarce, males may evolve contact guarding to protect their mates as effectively as possible against takeovers even though this means they cannot mate again while guarding a previous mate. © 1979 Taylor and Francis Ltd.