Changes in Phototaxis during the Larval Life of the Eyed Hawk Moth

Abstract

IN experiments on phototaxis in caterpillars, great variability is often found among the reactions to the same conditions of different individuals, or of the same individual at different times. No satisfactory analysis of the mechanisms underlying the phototaxis will be possible until we know, and can control, the factors governing this variability. The following results show that, at least in the eyed hawk moth (Smerinthus ocellata L.), the age of the larva is one important variable which should be more rigidly controlled than is usually done in work on caterpillar phototaxis.