The overall aim of the study was to assess the risk of gene flow from Brassica crops by insect mediated pollen transport. In order to evaluate the relative importance of different species in pollen transport, I measured abundance of flower visitors during crop development, and the foraging behaviour of five key pollinator species throughout the growing season, as influenced microclimate, crop phenology and the relative abundance of other pollinator species competing for flower resources. I found that: (i) insect abundance and diversity changed with crop phenology and Diptera was...