Geographical variation of photoperiodic adult diapause in Drosophila auraria.

Abstract

The variation of photoperiodic adult diapause was studied in Drosophila auraria strains originating in Japan at latitudes from 33.8 to 43.1°N. All the differently-located geographical strains showed a photoperiodic diapause. The critical daylength of these strains fell between 12 and 14h. The diapause intensity increases with an increase in latitudes. The duration of diapause was shorter at a photoperiod of 12 or 6h than at one of 10 or 8h in all the strains. This is because the photoperiod of 12 or 6h is less effective as a stimulus for the maintenance of diapause.