Why are there no insects in the open sea?
The air-filled tracheal respiratory system of insects prevents them from diving deeply in water. It is argued that this is the major factor in preventing insects from colonizing the open sea: they cannot descend sufficiently deeply in the daytime to escape being eaten by fish.
Maddrell
SH
Department of Zoology, Downing Street, Cambridge CB2 3ED, UK. shpm@hermes.cam.ac.uk.