Seasonal and geographic variation in the predation of gorse seed, ulex europaeus l., by the seed weevil apion ulicis forst.

Abstract

Gorse seed weevil, Apion ulicis Forst., was released into New Zealand in 1931 to help control gorse, Ulex europaeus L. This study examines the effect of the weevil in reducing annual seed production of gorse at three sites over 3 years. Weevils oviposited only during spring, and infested up to 90% of immature pods during that period. However, the many pods produced both earlier and later than this escaped attack. Lack of synchrony between weevil reproductive activity and gorse pod production limits the impact of the weevil on the annual gorse seed crop. Better adapted populations of Apion ulicis may exist in southern Europe and these could be introduced to increase predation on seed. © 1990 Crown.