Repeated heat shocks of animals carrying RpS3Aa.hs prolongs larval and pupal development and produces small adults. This defect is also seen if the animals are raised at 25oC without heat shock. Females carrying RpS3Aa.hs show a significant reduction in the number of eggs laid even at 25oC, and after heat shock treatment egg production is dramatically reduced so that no eggs are laid after 3 days. Vitellogenic egg chambers of heat shocked females have a variety of abnormalities, including disruption of the follicular epithelium, mislocalised or pyknotic nuclei and fused nurse cells.