Variation in copulation duration in Mnais pruinosa pruinosa Selys (Odonata: Calopterygidae). 1. Alternative mate-securing tactics and sperm precedence

Males of the damselfly Mnais pruinosa pruinosa were observed to use three different tactics to secure mates. The mean duration of copulation differed between the three observed tatics and resulted in varying degrees of sperm removal and insemination. It is shown that the last male to mate had almost 100% sperm precedence immediately after copulation regardless of the duration of copulation and therefore the quantity of sperm removed. In situations where less than 100% of rivals' sperm was removed the sperm from different males mixed within the female sperm storage organs over a period of about 6 days: sperm mixing produced variation in last male sperm precedence. The significance of sperm mixing in M. p. pruinosa is discussed in the context of the observed mate-securing tactics and the frequent female habit (37% of observations) of ovipositing without remating during an oviposition bout.