Effect of feeding by the western conifer seed bug, Leptoglossus occidentalis, on the major storage reserves of developing seeds and on seedling vigorof Douglas-fir

The impact of feeding by the western conifer seed bug (Leptoglossus occiden talis Heidemann) on storage reserves of developing seeds of Douglas-fir (Ps eudostuga menziesii (Mirb.) France) was studied by caging nymphal and adult seed bugs on cones during late-season development, and nymphs on cones dur ing early, mid- and late-season development. Analysis of the major storage reserves of partially damaged seeds revealed that late-season feeding by ea ch life stage and feeding by nymphs at all three stages of cone development significantly reduced the amounts of lipid and buffer-insoluble (crystallo id) protein in seeds at harvest by up to 78 and 97%, respectively. Seeds sh owing light to moderate damage on radiographs did not exhibit a reduction i n the amount of buffer-soluble (matrix) protein. Seeds damaged by feeding d uring early development compensated in part by continuing to synthesize lip id and crystalloid protein. Light or moderate damage to mature Douglas-fir seeds exposed to L. occidentalis in the laboratory reduced seedling emergen ce by > 80%, but the seedlings that emerged successfully appeared to suffer no adverse effects when grown under standard nursery conditions.