FLUORIDE LOADING OF LARVAE OF PINE SAWFLY FROM A POLLUTED SITE

1. The routes of transfer of fluoride to invertebrates and the relative fluoride loading of different body parts were studied in pine sawfly larvae (Diprion pini L.). Colonies of third and fourth instar larvae were collected from sites polluted with fluoride near an aluminium smelter. After collection the larvae were reared to pupation on unpolluted pine needles. 2. There were strong correlations between fluoride contents of larvae, larval faeces and exuviae with that of the pine needles on which they were collected. 3. Comparison of the fluoride content of the needles and faeces showed that the larvae absorbed < 2.5% of the ingested fluoride. 4. Fluoride was not detected in any of the pupae and there was no difference in pupal weights between the sites. 5. It was concluded that the fluoride measured in samples of the larvae was due principally to surface contamination and to the fluoride contained within the gut contents. 6. Despite considerable variation within samples from a site the fluoride concentration of whole larvae, pine needles, faeces and exuviae varied according to the location of the sample site with respect to the aluminium smelter.