Change in mandibular and mesosomal gland contents of maleXylocopa micans (Hymenoptera: Anthophoridae) associated with mating system.

Males ofXylocopa micans employ two mating systems in south-central Texas. They defend territories around flowering wisteria and redbud in March and April, and they maintain nonresource-based or landmark territories in July and August. Mandibular and mesosomal gland contents (analyzed by GC-MS) are different in bees employing the two mating systems. Mandibular glands contain only straight-chain hydrocarbons in bees defending floral resources, but include ethyl oleate in bees defending landmark territories. Mesosomal glands contain saturated, mono- and diunsaturated straight-chain hydrocarbons and methyl and ethyl esters of long-chain fatty acids. The major ethyl ester, ethyl oleate, comprises only 1.1% of mesosomal gland contents in bees defending floral resources but comprises 39.7% of gland content of bees defending landmark territories. These findings are discussed relative to the proposed sex pheromone function ofXylocopa gland secretions.