INTENSITY OF THE REPRODUCTIVE DIAPAUSE IN A STRAIN OF BRUCHUS-RUFIMANUS (BOH) (COLEOPTERA BRUCHIDAE) ORIGINATING FROM THE MEKNES REGION OF MOROCCO

Bruchus rufimanus is a univoltine bruchid beetle, developing at the ex pense of the seeds of Vicia faba L. The strain used in this study was collected in the Meknes region of Morocco. In this region, oviposition begins in April, when green pods are available on the host plant. but adults of the next generation do not emerge immediately after their i maginal moult. Adults in reproductive diapause remain in the pupal gal leries and emerge only when the seeds are exposed to moist conditions. Males, and a high percentage of females. terminated their diapause wh en exposed to long photoperiods (16:8 h LD and 18:6 h I.D). For both s exes, the additional presence of flowers of V. faba did not result in significantly higher rates of diapause termination. The intensity of d iapause depends on the time the insects spent inside the seeds. The di apause intensity is high when the beetles emerge in September, i.e. 8 months after oviposition. This intensity decreases when the time spent inside the seeds is long. The highest rates of diapause termination a re observed in insects emerging in January and February. Thirty percen t of these males terminate their diapause, even in short days. Such ch anges in diapause intensity, dependent on diapause duration, are fairl y frequent in insect living in temperate zone; their adaptive signific ance is discussed.