Reported ovo-viviparity in Heliocypha perforata (Odonata: Chlorocyphidae) – reassessment of the evidence, based partly on examination of the female reproductive system and mature eggs

Abstract

Heliocypha perforata (sensu lato) is a common stream-dwelling damselfly widespread in mainland tropical Asia. Recently a report has been published suggesting possible ovo-viviparity in this species, based on the interpretation of evidence from a short video sequence. This video is re-evaluated. The internal and external anatomy of the H. perforata female reproductive system, including mature eggs, is examined and illustrated, to the extent that this information casts light on the observations. Three competing hypotheses are considered: (1) a prolarva or larva was expressed from the female's oviduct, due to abnormal retention of the fertilized egg in the oviduct for several days; (2) an egg, deep in the oviposition substrate, previously laid and near hatching, was disturbed by the female's probing ovipositor and the prolarva hatched, becoming briefly caught in the in valves of the ovipositor; and (3) a small unidentified aquatic insect, probably of a different species and different order, was disturbed and similarly briefly caught in the valves. Based on the size and colour of the object relative to that of a mature egg and the likelihood of the event, hypothesis 3 is favoured.