Role of labial glands in nesting behaviour of Chalicodoma sicula (Hymenoptera; Megachilidae)

ABSTRACT. Chalicodoma sicula (Rossi) is a megachilid bee that constructs ball-shaped nests out of mud, which are usually attached to twigs or are built on the face of rocks. The nesting female collects sand from a nearby area while mixing it with secretion from labial glands in the head. Chemical analysis of labial glands by gas chromatography mass spectrometry reveal that the secretion is composed of long chain hydrocarbons, mainly hentriacontene and tritriacontene. Once the nest is completed it is covered entirely with a sand-labial gland mixture. In this form the nest is rendered hydrophobic and is not destroyed by rain for several years.