The Effect of Inbreeding and Crossbreeding on Numbers of Insects

Abstract

The possibility that inbreeding and crossbreeding may affect the numbers of insects in nature has been considered. Inbreeding Oncopeltus fasciatus Dal. resulted in fewer eggs and in some cases lower survival of progeny. Crossing the inbreds restored fecundity and survival, and in some cases resulted in more offspring than from the original strain. Hybrids of Oncopeltus from strains from Ontario, Canada, and Connecticut also showed evidence of hybrid vigor. This hypothesis meets the requirements of randomness proposed by Cole to account for cycles of abundance.