Observations on the Hibernation of Phlebotomus Papatasii (Dipt.)

Abstract

SummaryHibernation of P. papatasii in Palestine is primarily caused by low temperature, but cyclical (? hereditary) factors exist which modify the phenomena of hibernation to a certain extent, as indicated by the following facts.1. Occurrence of a gradually increasing number of resting larvae during autumn, with a maximum of hibernating larvae in the first winter generations.2. A gradually increasing prolongation of development during the late summer generation, with a maximum duration of development in the first winter generations in larvae kept at 30°C.3. The pupation of hibernating larvae kept at 30°C. in spring at the same time as of larvae kept in out-of-door conditions during the winter.There is always a certain number of resting larvae (2 to 12 per cent.) throughout the summer in otherwise active broods. This inhibition of development shows that a latent inclination to diapause exists in all generations, and that diapause may also be brought about by unfavourable conditions.No relation could be found between the interval between hatching and oviposition and asthenobiosis.