Geographic variation of diapause intensity in the spider mite Tetranychus urticae

摘要: . Eight strains of the spider mite Tetranychus urticae, originating from different localities in western and central Europe, with latitudes ranging 40.5 to 60oN, displayed marked differences period chilling at 4oC required for diapause termination under a diapause-maintaining short-day photoperiodic regime 19oC, which mites were transferred after cold period. The higher latitude originated longer was termination, suggesting presence gradient intensity, being deeper more northern origin strains. Two altitudes appeared have much than expected their latitudinal origin. In addition, these two mountain showed mutual notwithstanding fact that they similar altitudes; local climatic conditions probably act as strong selective forces regard depth. All be sensitive photoperiod during development. Diapause quickly completed by long-day (LD 17:7 h), but maintained 10:14h). However, even latter sensitivity gradually diminished eventually disappeared, thus leading ‘spontaneous’ diapause. length development, measured diapausing mites, varied between strains; it shorter southern strains. results indicate great variation intensity strains, is genetically determined may adaptive significance this widespread species. When young females had just entered kept ever periods time inducing been reared, before room, duration found decrease proportionally all three tested. These suggest intensification does not occur T. urticae; seems highest beginning diminish