PIGMENT MIGRATION IN THE EYES OF THE MOTH, EPHESTIA KUEHNIELLA ZELLER

Abstract

The accessory pigment cells in the eyes of Ephestia kuehniella migrate from their distal position between the cones to a more proximal position when exposed to light of sufficient intensity. A comparable, or even more marked, effect is produced by low temperatures, chloretone, high tensions of carbon dioxide, and by cutting the optic tract. Movement of individual cells can be induced by illuminating only a few of the ommatidia. This suggests that a hormonal method of control is unlikely. The fact that pigment cells can never be induced to migrate into the dark position once the optic tract has been severed suggests that the cells do not respond as independent effectors. In view of these several lines of evidence, though most of it is admittedly negative, it is possible that the migration of the accessory pigment cells in the eyes of Ephestia may be principally controlled by a nervous mechanism. It should again be emphasized that any conclusions based on the study of moths cannot necessarily be applied to other insects, let alone to Crustacea.