Agonistic behaviour in final-instar larvae of Episynlestes cristatus, Synlestes tropicus and Chorismagrion risi (Odonata : Synlestidae), and relationships within the 'Lestoidea'

Abstract

Larval agonistic displays are reported from three sympatric synlestid damselflies: Episynlestes cristatus, Synlestes tropicus and Chorismagrion risi. There were strong similarities between the species in the observed displays. Repertoires of all three species contained elements otherwise known only from larval Lestidae (conventionally interpreted as a member of the sister group to the Synlestidae). In night-time observations under infrared illumination different displays, some similar to those of coenagrionids, occurred. On the basis of similarities in larval displays I conclude that Chorismagrion risi, regarded on adult characters as an enigmatic form, is a member of the Synlestidae and that the Synlestidae and Lestidae are closely allied.