MORPHOLOGICAL AND ENDOCRINOLOGICAL ASPECTS OF PUPAL DIAPAUSE IN A FLESHFLY SARCOPHAGA ARGYROSTOMA

In the pupal diapause of Sarcophaga argyrostoma (Robineau-Desvoidy) development stops about 40 hr after the formation of the puparium, shortly after the head has become evaginated and before signs of the developing adult antennae are visible. This arrest of development has been shown for a number of organs. The combined ganglion does not separate into ganglia of head and thorax. The fat body breaks up into single cells, but the cells do not disintegrate further. The body muscles suffixed B (Crossley) do not break down. The heart-pericardial cells complex remains large as in the prepupa. When mature larvae are ligatured after the 'critical period' the hind part forms a puparium and develops up to and including the pupal moult. Then development stops at a state of differentiation identical with that in diapausing pupae. The pupal diapause is terminated by the injection of ecdyson. No effect of juvenile hormone or cholesterol has been demonstrated. In the presence of ecdyson juvenile hormone exerts a juvenilizing effect on adult development in that the eyes are small, and the adult cuticle develops only in the head and thorax, but not in the abdomen. Diapause occurs at the state of pupal development when ecdyson is at its lowest ebb. © 1968.