The Lipid Composition of Tenebrio Molitor Larvae

Abstract

Larvae of the meal worm (T. molitor) were raised at 20, 25, and 30[degree]C. The cultures were sampled periodically and were analyzed for total fatty acids, cholesterol, and phospholipids. Total lipid and neutral fat were calculated from these detns. The dependence of rate of growth and duration of larval life on humidity, as well as on temp., was confirmed. Total lipid, neutral fat, and total fatty acids became increasing proportions of the wet weight as larval growth progressed. Phospholipid declined very slowly, while total cholesterol remained practically constant in relation to wet wt. Neutral fat increased, while phospholipid decreased in relation to total lipid as the larvae developed; total cholesterol decreased very slowly. Examination of the data in terms of chemical heterauxesis revealed that total lipid is significantly tachyauxetic in relation to wet wt. With respect to total lipid, neutral fat and total fatty acids are tachyauxetic, while phospholipid and total cholesterol are bradyauxetic; these relationships are statistically significant. At the 3 temps. studied, the heterauxetic constants for each component do not differ significantly either by direct comparison or by analysis of variance. The trends in lipid composition during the development of Tenebrio larvae are consistent with those known to exist in other insect larvae and in vertebrate embryos. The heterauxetic constants represent a type of chemical ground plan of larval growth. This pattern appears to be unchanged by varying external conditions of temp. and humidity.