THE INFLUENCE OF EACH PARENT AND GEOGRAPHIC ORIGIN ON LARVAL DIAPAUSEIN THE BLOW FLY, CALLIPHORA-VICINA

The blow fly, Calliphora vicina R.-D. (Diptera: Calliphoridae), displa ys a larval diapause in response to short daylengths experienced by th e adult female. The range of daylengths inducing diapause varies among geographic populations of fly and differences are genetic in origin, being maintained under laboratory conditions. The critical daylength f or a southern, English strain is 14.5 hours of light and for a norther n, Finnish strain is 16 hours. Crosses between these strains revealed that diapause incidence was produced entirely by maternal induction an d was not influenced by the male. Diapause duration, in contrast, was affected by both parents; larvae with mothers of the northern strain a nd southern fathers entered diapause at the same rate as the pure bred northern larvae but emerged from it much more quickly. Thus diapause duration is a characteristic of the larvae themselves, influenced by t he genetic background of both parents. Copyright (C) 1996 Elsevier Sci ence Ltd