Male mating success in a natural population of Ischnura elegans (Vander Linden) (Odonata: Coenagrionidae)

A natural population of I. elegans was studied by mark-recapture techniques in Rome (Italy) during 25 days in June-August 1994. We marked 1043 3 and 957 9 and recaptured one third of them. Recaptured 3 6 were similar to unrecaptured ones in age at marking, date of marking and body size. Recaptured 9 9 were similar to unrecaptured ones in age and size, but were marked earlier. 53% of mature recaptured 3 c and 34% of 9 9 were never observed to mate. The maximum number of matings obtained by a 3 was 3, but 1 9 mated 7 times. The best predictor of male lifetime mating success (LMS) was mature lifespan. Mated 3 were smaller than unmated ones but body length was not correlated with LMS. The probability that 6 3 marked in copula obtained a second copulation was 7% higher than for 3 3 marked alone. We conclude that /. elegans 9 9 are clearly not monogamous in central Italy.