SMALL MALES EMERGE EARLIER THAN LARGE MALES IN DAWSON BURROWING BEE (AMEGILLA-DAWSONI) (HYMENOPTERA, ANTHOPHORINI)

Females of Dawson's burrowing bee (Amegilla dawsoni) are receptive to the males as they emerge but have become unreceptive by the time they begin to nest. in addition, there is a single emergence period per yea r lasting about a month. These factors are predicted to lead to protan dry and males of Dawson's burrowing bee do tend to emerge earlier in t he annual flight season than females. Moreover, even during a single d ay, emerging males tend to precede females. The degree of protandry, h owever, is size-dependent, with smaller males tending to precede large r ones, both over the course of the flight season and on any given day . Because small males are at a disadvantage in the fights that occur f or females, the earlier emergence of minor males may be a sexually sel ected response that reduces the likelihood that they will be displaced from potential mates by larger rivals.