Motion detection in insect orientation and navigation

The visual systems of insects are exquisitely sensitive to motion. Over the past 40 years or so, motion processing in insects has been studied and cha racterised primarily through the optomotor response. This response, which i s a turning response evoked by the apparent movement of the visual environm ent, serves to stabilise the insect's orientation with respect to the envir onment. Research over the past decade, however, is beginning to reveal the existence of a variety of other behavioural responses in insects, that use motion information in different ways. Here we review some of the recently c haracterised behaviours, describe the inferred properties of the underlying movement-detecting processes, and propose modified or new models to accoun t for them. (C) 1999 Elsevier Science Ltd. All rights reserved.