Migration and the Spatial Dynamics of an Aphid, Myzus persicae

Abstract

Six years aerial samples of M. persicae from suction traps enable the distribution of spring, summer and autumn migrations in Great Britain to be mapped. Summer migrations are geographically defined by the sugar-beet and potato crops. Autumn migrations are geographically erratic and means over several years are spatially uniform, reflecting the distribution of the many wild hosts. Spring migrations predominante inland in the south and center of England. Rate of over-wintering survival, from differences between autumn and spring maps, is concentrated between the South Downs and the Chilterns. This accounts for the Watson-Hurst equations fitting best when based on Rothamsted weather. It also points to some function of precipitation limiting survival in the west, while temperature limits population in the north. Although seasonal migration patterns are well defined, spatial variance shows no profound differences in behavior. Resource finding by M. persicae is highly efficient. This suggests the need for spatial, as well as temporal, analysis of populations to provide a common dimension for host plant distribution, weather, and other environmental variables.