Compartmentalization of Free Fatty Acids in Blood-Feeding Tabanus bovinus Females

Free fatty acids (FFAs) occupy unequal spatial distributions in the cuticle and internal lipid pool of female Tabanus bovinus Linnaeus (pale giant horsefly; Diptera: Tabanidae). Our findings indicate the highest concentrations of cuticular FFAs in the head and wings, and of internal lipid stores in the thorax and abdomen. In all extracts, C16:0, C18:0, and C18:1 were the dominant fatty acids. Several FFAs were absent from certain body compartments: C10:0 from inside the head, C19:0 from inside the head, wings, and legs, and C11:0 and C13:0 from the interiors of all examined body parts, while C20:5 and C20:4 were absent from both the cuticular and internal lipid pools in the wings. Cuticular C13:0 and C19:0 were detected only on the dorsal side of the thorax and abdomen. The uneven spatial distribution of FFAs suggests the existence of a selective lipid metabolism tailored to the functional and ecological demands of the insect.