White alder and Douglas-fir foliage quality and interegg-mass influences on larval development of gypsy moth, Lymantria dispar

Abstract—Individual families of gypsy moth collected from a single popu-lation exhibited different degrees of fitness when fed diets of white alder, asuitable broadleaf host, and Douglas-fir, an unsuitable conifer host. Membersof families on diets of Douglas-fir had significantly lower survival, longerlarval periods, lower pupal weights, and shorter pupal periods than membersof the same families fed alder. Foliar nutritional quality, including nitrogenlevel and allelochemical composition (terpenes and phenols), was consideredthe key factor responsible for these differences. Growth parameters differedsignificantly for families within diet treatments, indicating that the geneticresources of a family did affect performance somewhat. The influence of afamily's genetic resources on larval survival was most notable when larvaewere under the greatest nutritional stress.
Key Words—Douglas-fir, Pseudotsuga menziesii, gypsy moth, Lymantriadispar. Lepidoptera, Lymantriidae, insect-host plant relations, phenolics,terpenes. white alder, Alnus rhombifolia.