As part of a search for natural enemies of the gypsy moth (Lymantria dispar), virus-infected samples were collected near Toulouse, France. Light and electron microscope studies confirmed that the French strain is a multinucleocapsid nuclear polyhedrosis virus (MNPV). In vivo bioassays using the New Jersey strain of L. dispar, and comparing L. dispar MNPV (LdMNPV) strains from France, North America and Korea, showed that the French strain was the least active, whereas the North American strain had the highest activity. The viral efficacy of all strains was enhanced 200 to 1300-fold in the presence of 1% fluorescent brightener. The enhancement was highest in the American strain and lowest in the French strain. French LdMNPV (LdMNPVF) DNA cut with four restriction enzymes (BamHI, EcoRI, HindIII, and NotI) revealed minor fragment size differences, but many similarities when compared to the North American and the Korean strain. PCR amplification of a LdMNPV early gene (G22) was detected in the North American and the Korean strain, but not in the French strain.
The effects of tannic acid on mean values and genetic variation in fitness-related traits (mass, relative growth rate) and specific activities of digestive enzymes (total proteases, a-glucosidase and lipase), and genetic variation in their plasticity, were investigated in fifth instar larvae of Lymantria dispar L. (Lepidoptera: Lymantriidae) originating from two populations with different host use histories (oak and locust-tree). The two populations did not differentiate with respect to fitness-related traits, i.e. adverse effects of tannic acid were similar in both populations. However, Robinia larvae, which originated from the locust-tree forest, were characterized by higher total protease and lipase activity and lower a-glucosidase activity than Quercus larvae, which originated from the oak forest. Higher plasticity of lipase and lower plasticity of a-glucosidase in response to tannic acid were also recorded. Quantitative genetic analysis revealed mostly significant expression of genetic variation in the examined traits and trait plasticity, suggesting the potential for evolution of adaptive plastic responses to new environmental conditions and presence of a stressor. The genetic correlations observed between the environments significantly differed from “one”, which indicates there are no constraints on the evolution of trait plasticity., Marija Mrdakovic ... [et al.]., and Obsahuje seznam literatury