The effects of freezing temperatures on the developing egg of Leptohylemyia coarctata Fall. (Diptera, Muscidae) with special reference to diapause development

Abstract

The later stages of diapause in the egg of L. coarctata are completed rapidly at −20°C to −24°C. At −24°C the rate of diapause completion is about 180 times faster than at −6°C and about 80 times faster than at 3°C. These results suggest that there are at least two phases in diapause development—an initial synthesis, perhaps of neurohormone, which will not occur at −18°C to −24°C. This is followed by a process ending in release of the synthesized material which is greatly accelerated by relatively short exposures at −20°C to −24°C; longer exposures kill the eggs, probably because they freeze.