“…Halictids are important bees for studies of social evolution because they show enormous intra- (Sakagami and Munakata, 1972;Yanega, 1988;Eickwort et al, 1996;Richards, 2000;Soucy, 2002) and inter-specific variation in social behavior. Variation in social behavior within species is often linked with altitude and latitude such that populations at high elevation and latitude tend to be solitary, while populations at lower elevation and latitude tend to be eusocial (Sakagami and Munakata, 1972;Packer et al, 1989;Eickwort et al, 1996;Soucy, 2002;Soucy and Danforth, 2002). Diversity in social behavior among species was often thought to be due to frequent independent origins of eusociality in halictids (Eickwort, 1986) but recent molecular studies within and among genera of Halictinae have suggested that reversals from eusociality to solitary nesting may be common (Packer, 1997;Danforth, 1999;Danforth et al, 1999Danforth et al, , 2003Brady et al, 2006).…”