Effects of elevated temperature and carbon dioxide on the nutritional quality of leaves of oak (Quercus robur L.) as food for the winter moth (Operophtera brumata L.)

摘要

Pedunculate oak trees were grown in ambient, 3deg C above ambient temperatures and ambient and 340 ppm above ambient CO2. Indirect effects on O. brumata were analysed by feeding larvae maintained at constant conditions with leaves from trees grown in different conditions. Direct effects were investigated by growing trees and moths in the same conditions. Larvae in constant conditions assimilated less from elevated than ambient temperature leaves, resulting in lighter pupae and fewer, lighter eggs. Larval pupal mass and fecundity did not vary between different CO2 leaf diets. Nitrogen was reduced in elevated temperature and CO2 leaves. Increased fibre in elevated temperature leaves prevented increased consumption, reducing pupal mass and fecundity. Reduced fibre in elevated CO2 leaves allowed increased consumption. Larvae reared with trees from which they were fed had constant pupal mass in all treatments, but pupated earlier at elevated temperature. Pupal mass and fecundity was not affected when larvae and trees were both at elevated temperatures, because the duration of larval and leaf development decreased equally. It is concluded that anticipated climatic change will have no nutritional effect on O. brumata development.