Behavioural protandry in the damselfly Mnais pruinosa costalis Selys in relation to territorial behaviour (Zygoptera : Calopteryghdae)

The reproductive strategy of the male M. p. costalis can be defined as an a ttempt to maximize the number of females mated. Males exhibit wing colour d imorphism: one form has orange wings, and the other has hyaline wings which resemble female wings. The former is usually territorial and the latter us es sneaky mate securing tactics around the territories of orange-winged mal es. Although the length of the emergence period varied from year to year, n o evidence of protandry was observed. Studies over 10 years have shown that if the length of the sexually active period in females is stable, the oran ge-winged males should become sexually mature before females do to achieve maximal reproductive success. On the other hand, the hyaline-winged males d o not mature before females due to the fact that they utilize the territori es of orange-winged males. This study shows that behavioural protandry shou ld be considered a reproductive strategy of the orange-winged males for est ablishing territories.