THE EFFECT OF TEMPERATURE ON THE WINGS OF DIMORPHOS/DIMORPHOS VESTIGIAL-PENNANT/VESTIGIAL IN DROSOPHILA MELANOGASTER

¹ Washington Square College of Arts and Science, New York University

1. The genotype di/di vg^p/vg was examined at 2° intervals from 16° to 32°.

2. The length of the wings on the males and the females decreased from 16° to 28° and increased from 28° to 32°. The wings of the females were longer than those of the males at all temperatures.

3. The area of the wings of the males decreased from 16° to 28° and then increased to 32°.

4. The critical temperature for both the length and area of the male wings is apparently 28°.

5. The area of the wings of the females decreased from 16° to 22° and increased from 22° to 32°. The resulting U-shaped curve is very similar to that reported previously for vg^p/vg but the values are approximately double for the di/di vg^p/vg genotype.

6. The critical temperature for the female wing area appears to be at 22° and for wing length at 28°.

7. The di gene lowers the critical temperature for wing area 2° in the vg/vg female and the vg^p/vg female.

8. The critical temperature is a function of the genotype.

9. The males have wild type wings with minor marginal nicks at all temperatures. Wings with perfect margins were produced at 16° (19%), 18° (11%), 26° (10%), 28° (7%), 30° (7%), and 32° (28%). The marginal defects are obviously thermolabile.

10. The wings of the females varied around over-sized "antlered" with the occasional appearance of a "strap" wing from 16° to 26°. Phenotypes resembling the mutant alleles antlered, snipped, carved, and notched appeared at 24° and 26°. The wings were predominantly "notched" to "nicked" from 28° to 32°. Perfect margins were observed on twenty-four per cent of the wings developed at 32°.

11. The di gene lowered the wing pattern threshold some 12° in the females. In the males, this threshold was lowered below the viable range and only normal wings were produced.