Diapause and metamorphosis of the blowfly,Lucilia sericataMeig
1. Diapause inLucilia sericatais caused by unfavourable conditions during the larval or prepupal period.2. Diapausing prepupae usually contain a higher proportion of dry matter than do normal individuals.3. Diapause occurs because the corpus allatum (Weismann's ring) is not producing the necessary hormone.4. Diapause is ended when prepupae are removed from sand to empty tubes. Probably the corpus allatum is stimulated by a nervous reaction; the reaction is not due to an increase in the rate of metabolism.5. Low temperatures (5° C.) do not affect the hormone, but high ones (35–37° C.) destroy it.6. Prepupae ofLucilia sericatahave salivary glands which are dilated to nearly a quarter the body size. The contents serve as a store of water during diapause.7. Diapausing prepupae after desiccation drink water and return to their original body weight. The water increases the volume of blood in circulation, and the blood controls the size of the adult produced.8. Diapause in nature enables the species to survive unfavourable conditions.