Effects of ventral nerve cord and peripheral nerves severance on the form and pupation of Danais chrysippus larvae (Lepidoptera)

Severance of ventral nerve cord in early and partially fed fifth (ultimate) instar of D. chrysippus induced both the systemic and partial body distens ions, inhibition of pupation or production of larval - pupal intermediates and inhibition/delay in the synthesis and release of prothoracicotropic hor mone from the neurosecretory cells of the brain. It seems that most of thes e effects occur due to interruption in feeding which sends modified proprio ceptive inputs from gut wail to the brain. A great deal of variation in foo d consumption was also found following this surgical manoeuvring. While ser verance of most of the peripheral nerves had no effect on developmental eve nts, severance of nerves arising from last abdominal ganglion caused total mortality presumably due to failure of discharge of the excrement.