摘要:

not available

ISSN:1923-4287    

DOI:10.1139/cjr41d-032

出版商:NRC Research Press    

年代:1941

数据来源: NRC

摘要:

Methods of sampling, determination of reproductive capacity, and analysis of data are described. Various physical measurements are positively correlated with reproductive capacity, but regression equations are unsatisfactory for estimation of fecundity outside of the population in which the relationships have been determined, due to variability in the degree of joint variation of size and fecundity under different feeding conditions. Field populations developed on white spruce are more fecund than those developed on black spruce; reductions of 30% or more may result from periodic food shortage.Reproductive capacity of females emerging over a period of three to five years in each of 20 populations, failed to show any consistent trend in relation to the diapause period. From this, and also from the slight reduction in eonymphal dry weight over extended intervals at favourable temperature, it is concluded that the destruction of eonymphal reserves during diapause proceeds very slowly and has no practical effect upon fecundity of females issuing after prolonged diapause.

ISSN:1923-4287    

DOI:10.1139/cjr41d-033

出版商:NRC Research Press    

年代:1941

数据来源: NRC

摘要:

This final paper in the series on diapause in the spruce sawfly describes the direct and indirect influences of diapause on epidemiology in different parts of the distribution range in eastern North America. These relate to duration of diapause, degree of diapause in overwintered cocoons, and proportions of the population surviving to participate in the continuation of the infestation. The nature of infestations in different areas is described briefly.Discussion of features of intraspecific differences, and a summary of conclusions derived from all five papers in the series, are also included.

ISSN:1923-4287    

DOI:10.1139/cjr41d-034

出版商:NRC Research Press    

年代:1941

数据来源: NRC