Activity of asynchronous flight muscle from two bee families during sonication (buzzing).

The indirect flight muscles of bees are used to produce a variety of actions in addition to flight, including sonication, which has a higher frequency than flight. We observed the dynamic movement of the scutum during sonication and the transition from tethered flight to sonication. During sonication, the scutum oscillated above its rest position, indicating that the conformation of the structural components of the thorax had been altered. Sonication vibrations of the thorax occurred by deformation of the scutum rather than by opening of the scutal fissure and are smaller than vibrations associated with flight. During tethered flight, the ratio of muscle activity (recorded via electromyograms) between the dorsal longitudinal muscles and the dorsoventral muscles approached 1, but during sonication the ratio was significantly higher (up to 4.0). This increase may cause the dorsal longitudinal muscles to contract further than the dorsoventral muscles and close the scutal fissure during sonication, so limiting the displacement of the wings and 'decoupling' them from the indirect flight muscles.

Identification of thoracic gland constituents from maleXylocopa spp. latreille (Hymenoptera: Anthophoridae) from arizona.

Some male carpenter bees (Xylocopa spp.) possess massive propodeal exocrine glands that produce copious quantities of multicomponent blends of lipoidal material. Some of these compounds are volatile, producing a "flowery" aroma that can be easily detected several meters downwind from a territorial male. Chemical characterization of these secretions showed them to be blends of terpenoid compounds or fatty acid derivatives. InX. varipuncta, the mixture is composed of alltrans-geranylgeraniol, alltrans-farnesal, and an isomer of 3,7, 11-trimethyl-2,7,10-dodecatrienal in an approximate 9∶6∶1 ratio. The secretion ofX. micheneri contains isopropyl oleate, (Z)-11-eicosen-1-ol, oleyl alcohol, and methyl palmitate at approximately 63∶24∶11∶1. We hypothesize that these compounds act as pheromones that aid in attracting and holding conspecific females to symbolic nonresource encounter sites where mating occurs. They also appear to have utility as chemotaxonomic markers at the subgeneric level.