Effect of moisture on the lipid content and composition of two strains of Tenebrio molitor L. (Coleoptera, Tenebrionidae)

Abstract

Tenebrio molitor larvae reared on dry wheat shorts grew faster and accumu-lated larger lipid reserves when water was available on a free-choice basis than when it was not. Triglycerides, the largest lipid fraction, increased most in response to water, free fatty acids and phospholipids increased less and hydrocarbons, sterols, sterol esters, mono and diglycerides did not change. The fatty acid composition of the triglycerides and free fatty acids also did not vary in response to water. The faster growing strain of mealworms, under both moist and dry conditions, also had larger fat reserves at pupation than did the slow growing strain, mostly because of increased triglyceride accumulation. The fatty acid composition of the triglyceride and free fatty acid fractions showed only minor quantitative differences between strains. The natural preference of T. molitor larvae for moist situations would result in larger lipid reserves for metamorphosis and early adult metabolism as well as more rapid larval development.