FLIGHT AND SWIMMING REFLEXES IN GIANT WATER BUGS

Abstract

Giant water bugs (Lethocerus americanus and Benacus griseus Hemiptera, Belostomatidae) swim when suspended free of the substrate in contrast to terrestrial insects which fly. Suspended bugs respond initially to wind with increases in rate and duration of swimming followed by decreases in both. In water, swimming is stimulated by hair beds on the trochanters at the coxotrochanteral joints. In some bugs, flight or wing opening occurred in wind; these responses are mediated by hairs on the head. An elaborate pre-flight behavior, necessary to unlock the wings, eventually inhibits swimming in suspended animals. In spite of fused ganglia, there was no evidence for interganglionic transmission of impulses affecting leg action in swimming. There is evidence that the swimming reflex is a general phenomenon which might be an aquatic modification of the flight reflex.