Abstract
Males of the vernal ground nesting bee,Colletes cunicularius, actively search their nesting aggregations for emerging virgin females. Males often detect and unearth preemergent virgin males and females which have not yet dug up to the soil surface. Field experiments indicate that the odors from one unmated individual are sufficient to both excite males and direct their excavation of the virgin bee. A volatile component of this species' mandibular gland secretion, linalool, increases flight activity and directs local search behavior in aerially patrolling males. Linalool is detectable by coupled gas chromatography-mass spectrometry in association with the digging activities of either sex.