The effects of selective breeding on the laboratory propagation of insect parasites

Abstract

The formal application of certain animal breeding methods has been investigated in the laboratory propagation of a chalcid parasite, Microplectron fuscipennis Zett. An account is given of the methods used with reference to their value in the propagation of other insect parasites. Through selective breeding, laboratory production permitted the distribution of 889 million parasites over the spruce sawfly infested area in Canada. Selection in the breeding lines brought about a continuous decrease in the number of sterile males from 35 to 2%; an increase in the mean number of offspring per mother from 34 to 68 and an almost equal reduction in variability of development, oviposition and length of adult life. Tests are reported on the effects of inbreeding and outbreeding on these lines using wild and laboratory-reared stock.