NESTMATE RELATEDNESS IN A COMMUNAL BEE,PERDITA TEXANA (HYMENOPTERA: ANDRENIDAE), BASED ON DNA FINGERPRINTING

Perdita texana is a facultatively communal bee species with up to 28 females per nest. We used multilocus DNA fingerprinting to test the hypothesis that nestmates are more closely related to each other than are nonnestmates. The mean band sharing proportion among pairwise nestmate comparisons did not differ significantly from the mean among nonnestmate comparisons [P = 0.787 (df = 484)]. Although mean band sharing proportions did not differ among nestmates and nonnestmates, some nestmates show very high band sharing proportions (in excess of the upper 95% confidence limit for the nonnestmate mean). These individuals almost certainly are related, probably as half-sib sisters, however, they comprise a very small percentage of the nestmate populations. Our results indicate that kin selection is unlikely to play an important role in the evolution and maintenance of communal nesting. Communal societies most likely arise because of the mutualistic benefits of cooperative nesting, including accelerated nest founding and improved nest defense.