© 1972 by The Society for Integrative and Comparative Biology
Evolutionary Trends in the Subsocial Sawflies Belonging to the Neodiprion abietis Complex (Hymenoptera: Tenthredinoidea)
Department of Zoology, University of Toronto Toronto 181, Ontario, Canada
Populations of the Neodiprion abietis complex occur on firs and spruces in North America. A distinct western population on white fir differs greatly in appearance from the four eastern strains, of which two feed on balsam fir and one each on black and white spruce respectively. Differences in developmental rates, larval survival on the various food plants, and host selection by the females supply the isolating mechanisms between the strains in the field. All populations cross-mated freely in the laboratory, and the resulting hybrids indicate the transmission of Several morphological and physiological characters. It is speculated that the ancestral line of the complex fed on pine before a jump to spruce and then to balsam was made.