Impact of Apion ulicis Forster on Ulex europaeus L. Seed Dispersal

The impact of the weevil Apion ulicis on the dispersal and quality of gorse (Ulex europaeus) seeds was examined in southern Chile in 1991 and 1992. Seed dispersal was assessed by counting the number of seeds captured by rows of seed traps placed at 0.7, 1.4, and 2.8 m from 12 weevil-infested and 12 weevil-free gorse plants arranged in a split-plot randomized complete block design. Seed weight and germinability were also measured. The influence of gorse pod location on host utilization by the weevil and the hypothetical subsequent change on seed dispersal were also studied. Gorse seed production and dispersal were significantly (P ≤ 0.001) decreased by A. ulicis in 1991 but not in 1992. Individual seed weight and germinability were not adversely affected by weevil infestation. Pod location did not affect host utilization by the insect, nor did it influence seed dispersal or quality.