Approaches to the ethology of hydroids and medusae (Cnidaria, Hydrozoa)

Abstract

The behavioural patterns of 26 species of Antho- and Leptomedusae (with or without medusa stage) were investigated by video recordings. The analysed activities were: answers to mechanical stimuli, prey capture and ingestion, digestion, egestion, and swimming. The quantity of behavioural patterns identified in the small number of hydrozoan diversity studied so far is sufficient to demonstrate that these supposedly simple animals have evolved a complex array of responses to both external and internal stimuli.