Sexual differences in development and behaviour of larval Ischnura verticalis (Odonata: Coenagrionidae)

The emergence period of Ischnura verticalis from a pond in southern Ontario lasted at least 97 days; the sex ratio of emerging larvae was not significantly different from 1:1. A 17-month study on larvae from the same pond indicated that the life cycle was univoltine and that male larvae tended to develop faster than female larvae. Analysis of instar distributions of larval I. verticalis collected from a series of ponds also indicated that males …