The Natural Mortality of Erioischia brassicae (Bouche) (Dipt., Anthomyiidae): Life Tables and their Interpretation

Abstract

1. Life tables have been constructed for six generations of the cabbage rootfly as it occurs in one field at Wellesbourne. 2. The importance of particular causes of death are discussed in relation to the life tables. 3. Whilst rootfly populations have remained remarkably constant over the years, no particular factor seems to be concerned in this regulation. 4. Varying combinations of all factors, possibly sequentially modified by weather conditions, seem to cope with any potential increase or decrease in numbers before the end of the generation in which the change occurs.