Abstract
Flight activities of Colias erate were studied at high and low altitudes in Nagano Prefecture in summer from the viewpoint of body temperature of flying butterflies and environmental factors. Their flight activities were depressed by low body temperature at a high altitude and by high body one at a low altitude. At a high altitude the body temperature of flying butterflies ranged from 25 to 30℃ when it was fine and many butterflies flew at the range in which the limited environmental factors happened many times in the suitable condition for flight because the climate changed so rapidly that the suitable condition for flight was not stable. At a low altitude the flight activities of butterflies peaked twice in the morning and afternoon. On the other hand light intensity showed a unimodal peak at 13:00 (or 14:00) and from 12:00 to 14:00 the flight activities tended to have negative correlation to the light intensity. When the light intensity was high, butterflies could not fly because high radiant heat might raise the body temperature above the upper limit for flight. Consequently the different types of daily flight activities in Colias erate appeared according to the different environmental conditions between high and low altitudes at the same season; undecided type at a high altitude and bimodal type at a low one.
