Fluoride loading of larvae of pine sawfly from a polluted site.
Abstract
The routes of transfer of fluoride to invertebrates and the relative fluoride loading of different body parts were studied in larvae of Diprion pini. Colonies of 3rd- and 4th-instar larvae were collected from branches of Pinus nigra at sites polluted with fluoride near an aluminium smelter in Wales. After collection, the larvae were reared to pupation on unpolluted pine needles. There were strong correlations between fluoride contents of larvae, faeces and exuviae with that of the pine needles on which they were collected. Comparison of the fluoride content of the needles and faeces showed that the larvae absorbed <2.5% of the ingested fluoride. Fluoride was not detected in any of the pupae and there was no difference in pupal weights between the sites. It is 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. Despite considerable variation within samples from a site, the fluoride concn of whole larvae, pine needles, faeces and exuviae varied according to the location of the sample site with respect to the aluminium smelter.