Chemoattraction ofBiomphalaria glabrata (Gastropoda: Planorbidae) to lipid standards and lipophilic factors in leaf lettuce and Tetramin.

Chemoattraction of individualBiomphalaria glabrata snails for lipid standards and lipophilic fractions of leaf lettuce and Tetramin were studied in a Petri dish bioassay. Snails were more significantly attracted to a whole Tetramin lipophilic fraction than that of leaf lettuce. Thin-layer chromatography showed that major neutral lipid fractions in Tetramin were triacylglycerols, free fatty acids, and free sterols, and in leaf lettuce were free fatty acids and a mixed free sterol-chlorophyll fraction. Snails were significantly attracted to both the free fatty acid and free sterol fractions from Tetramin, but only to the free fatty acid fraction from leaf lettuce. Snails were significantly attracted to a mixed lipid standard containing equal amounts of phosphatidylcholine, cholesterol, oleic acid, triolein, and cholesteryl oleate. Of four individual neutral lipid standards tested, i.e., cholesterol, oleic acid, triolein, and cholesteryl oleate, snails were only attracted to cholesteryl oleate.