Aspects of diapause and its genetics in northern drosophilids

The adult diapause of Drosophila subarctica, D. littoralis and D. bifasciata and the larval diapause of Chymomyza costata are described along with the geographic distribution of the diapausing races in northern Scandinavia. The northern populations of these species are univoltine and the adult diapause appears to depend on the photoperiod and the larval diapause on temperature. The genetics of the diapause in D. littoralis was elucidated by crosses between univoltine and multivoltine strains. Multivoltinism appears to be dominant over univoltinism and the genetic determination of diapause polygenic.