Selective uptake and lack of dealkylation of phytosterols by cactophilic species of Drosophila

The selective absorption of cholesterol and campesterol and discrimination against sitosterol was demonstrated with Drosophila mojavensis and Drosophila nigrospiracula , using a synthetic medium and 2 natural host cacti. Preferential absorption of trace amounts of phytosterols from a large quantity of other lipids occurred when D. arizonensis and D. mojavensis were reared from agria cactus. The absence of dealkylation of sitosterol to cholesterol was demonstrated with D. mojavensis and D. mettleri , reared on a sterol‐deficient medium supplemented with sitosterol.