EYE FACET NUMBER AS INFLUENCED BY TEMPERATURE IN THE BAR-EYED MUTANT OF DROSOPHILA MELANOGASTER (AMPELOPHILA)

Abstract

1. Temperature is an important factor in the determination of facet number in the bar-eye of Drosophila. 2. A lower developmental temperature results in a higher facet number, and conversely a higher temperature results in a lower facet number. 3. With each 10° drop in temperature between 29° and 15°, the facet number is increased on the average 2.6 times in the males and 3.5 times in the females. 4. The increase in facet number except at the extremes is directly proportional to the increase in the area of the eye, and facet-size is therefore a constant within these limits. 5. Light, and amount of food, as they occur in these experiments are not important factors in the determination of facet number. 6. Temperature is effective only during the larval period.