The major releasing stimulus in intraspecific nest defense of Lasioglossum zephyrum is the odor emitted by a non-resident bee. Non-resident bees older than two days emit the releasing odor and elicit aggressiveness by guard bees, whereas younger non-resident bees are accepted more often. Defense motivation is a function of nest age and/or ontogeny. As nests become older and cells are con-structed and provisioned, there is a gradual increase in guard aggressiveness, although no one attribute of nest ontogeny (such as cell construction) seems to be a definitive point at which nest defense is initiated, nor is there any specific day after the emergence of the first bee when nest defense begins. The guard plays the major role in rejecting intruders, although other members of the colony may do so if a non-resident bee passes the guard and enters the nest.
Bell, William J.; Breed, Michael D.; Richards, Kenneth W.; and Michener, Charles D., "Social, Stimulatory and Notivational Factors Involved in Intraspecific Nest Defense of a Primitively Eusocial Halictine Bee" (1974). Ba. Paper 48.
Available for download on Friday, January 01, 4500