Biosynthesis of wax in the honeybee, Apis mellifera L.

Abstract

The composition of the cuticular wax of the honeybee is quantitatively different from that of the comb wax. The major component of the cuticular lipids is hydrocarbon, which comprises 58% of this wax. In contrast, hydrocarbon comprises only 13–17% of the comb wax, and monoester is the largest component ( Tulloch 1971). The major fractions of the cuticular wax were analyzed by gas-liquid chromatography, and were shown to be qualitatively similar to those of the comb wax. The incorporation of injected radio-labelled acetate into hexane extractable wax by worker honeybees not actively producing comb wax resulted in the recovery of much of the radioactivity in the hydrocarbon fraction. In insects actively producing comb wax, a higher percentage of radioactivity was recovered in the monoester fraction. A dramatic effect of age on the distribution of radioactivity from acetate into the various wax fractions from honeybees studied in the summer months was observed. In insects from eleven to eighteen days following emergence to adults, the major wax component synthesized was monoester, whereas in younger and older insects, hydrocarbon was the major wax component formed. Both in vivo and in vitro experiments using insects actively producing comb wax showed that the abdomen produced significant amounts of monoester, hydrocarbon, and other esters, whereas the thorax synthesized mostly hydrocarbon. These data show that the epidermal cells and wax glands each produce a wax with a distinct composition, and that the age and seasonal differences observed in wax synthesis are due to the presence or absence of active wax glands.