© 2001 Heron Publishing—Victoria, Canada
Effect of feeding by the western conifer seed bug, Leptoglossus occidentalis, on the major storage reserves of developing seeds and on seedling vigor of Douglas-fir
Sarah L. Bates (1), Cameron G. Lait (1), John H. Borden (1) and Allison R. Kermode (1)
1. Centre for Environmental Biology, Department of Biological Sciences, Simon Fraser University, Burnaby, British Columbia V5A
1S6, Canada / Received March 23, 2000
Summary
The impact of feeding by the western conifer seed bug (Leptoglossus occidentalis Heidemann) on storage reserves of developing seeds of Douglas-fir (Pseudostuga menziesii (Mirb.) Franco) was studied by caging nymphal and adult seed bugs on cones during late-season development, and nymphs on cones
during early, mid- and late-season development. Analysis of the major storage reserves of partially damaged seeds revealed
that late-season feeding by each life stage and feeding by nymphs at all three stages of cone development significantly reduced
the amounts of lipid and buffer-insoluble (crystalloid) protein in seeds at harvest by up to 78 and 97%, respectively. Seeds
showing light to moderate damage on radiographs did not exhibit a reduction in the amount of buffer-soluble (matrix) protein.
Seeds damaged by feeding during early development compensated in part by continuing to synthesize lipid and crystalloid protein.
Light or moderate damage to mature Douglas-fir seeds exposed to L. occidentalis in the laboratory reduced seedling emergence by > 80%, but the seedlings that emerged successfully appeared to suffer no
adverse effects when grown under standard nursery conditions.
Keywords:
lipid, protein, Pseudotsuga menziesii, seed storage reserves, seedling vigor.
