CHANGES IN SOME ECOLOGICAL CHARACTERS CAUSED BY THE DIFFERENT MECHANISMS OF DENSITY REGULATION IN THE EXPERIMENTAL POPULATIONS OF THE ALMOND MOTH EPHESTIA CAUTELLA WALKER

Abstract

Some ecological characters of individuals were compared among four populations of the almond moth. The populations were bred for about 20 generations under the experimentally controlled conditions. When the food was supplied at an interval longer than the mean length of a life cycle of the moth, the duration of the developmental period of the individuals becomes longer than that of the individuals in the population with short interval of food supply. The individuals in the population which had been parasitized with the Ichneumon wasp, Nemeritis canescens GRAV., become slower in their development and slightly lower in their susceptibility to the parasitoid wasp than the individuals in the population free from its parasitization. These differences of the ecological characters of the individuals among populations may be caused by the action of the different mechanisms of density regulation. The individual difference of the head width of the moth can not be seen among these populations.