Fluoride loading of a lepidopteran larva (Pieris brassicae) fed on treated diets

Experiments to assess the impact of dietary fluoride on larvae of Pieris brassicae were designed to substantiate field observations that at polluted sites little fluoride is absorbed by insect larvae and that most of the body load is caused by surface contamination. Treatment with fluoride as HF or AlF3 had no effect on pupal weight of Pieris and we conclude that fluoride, at concentrations likely to be found on vegetation at polluted sites, is unlikely to have a direct impact on the growth of chewing herbivores. Fluoride in the gut formed the biggest component of the total body load. A significant amount of fluoride was detected in exuviae, but resulted from surface contamination. When larvae from polluted food were transferred to untreated food it took several days for the fluoride content of the faeces to return to background levels.