Crossing between nondiapausing and diapausing races of Sarcophaga peregrina

The temperate race (D) of S. peregrina undergoes pupal diapause in response to certain environmental conditions of photoperiod (13L:11D-11L:13D) and temperature (under 20 degrees C). The tropical race (ND) does not do so under the same circumstances. The tendency toward diapause was suppressed 30-40% of the hybrids of crossings D female x ND male and ND female x Dmale even under such short day and low temperature conditions as 11L:13D-9L:15D, 20 DEGREES C. For entering diapause, the hybrids rrequire a shorter day length (13L:11D) than that of (D) parents (15L:9D).