Abstract

F. Medjdoub-Bensaad, M. A. Khelil and J. Huignard

In this study, the conditions of colonisation of the broad bean Vicia faba L. by the adults of the Coleoptera Bruchidae Bruchus rufimanus Boh. were analysed in the region of Kabylia in Algeria. B. rufimanus adults began to colonise the V. faba cultures in February after termination of a larval and a reproductive diapause. Males appeared in February and had terminated their reproductive diapause. Females began to colonise the broad bean culture in March; they terminated their reproductive diapause after consumption of nectar and pollen of the host- plant flowers. The adult density depended on the abundance of the trophic resources at the beginning of adult colonisation phase. The females oviposited on the green pods as soon as they appeared on the plants and laid on these pods as long as they did not became mature. The first and the secondary larval instars developed in maturing seeds in the green pods. The last larval instars and the pupae developed in dry seeds after harvesting and storage in granaries. A high inter- individual variability in the duration of the postembryonic develop-ment was observed in this study. The adaptive signification of this developmental heterogeneity was analysed in this study.