LABORATORY DETERMINATIONS OF THE DAILY FLIGHT TIMES OF SEPARATE SEXES OF SOME MOTHS IN NATURALLY CHANGING LIGHT

Abstract

Experiments were carried out in the laboratory to define the flight times of separate sexes of the moths Ectropis, Malacosoma, Halisidota, Choristoneura, Nepytia, Lambdina, and Anagasta (Ephestia), when the only naturally varying environmental parameter was light. A sex difference in the flying-activity times was found in the last five insects listed above. There were different degrees of sex difference. Nepytia, Halisidota, and Anagasta males possessed an activity peak just prior to sunrise, as well as at other times during the night, whereas the females did not possess this peak. Lambdina males had an early, broad peak prior to sunrise. There were some changes in the activity pattern of male Choristoneura and Halisidota with increasing age from emergence, and in the amount of activity of some kinds of females.A study of the iris pigment in the eyes of Ectropis, Nepytia, and Anagasta showed that the sex differences in the activity patterns are probably not related to differences in the pigment position.