Phylogeography of the Socially Polymorphic Sweat Bee Halictus Rubicundus (Hymenoptera: Halictidae)

Abstract

The evolution of sociality in insects holds a central place in evolutionary theory. By examining the phylogenetic patterns of solitary and social behavior and how they correlate with ecological variables, we may identify factors important in the evolution of sociality. In this study, we investigated historical and biogeographical patterns of sociality in a socially polymorphic bee species (one that demonstrates both social and solitary nesting behavior). This unique system allows for a more powerful examination of evolutionary transitions in sociality than interspecific studies of obligately social and solitary species. We conducted a phylogenetic analysis among populations of the halictine bee Halictus rubicundus and then identified relationships among mitochondrial DNA sequence data, sociality, environmental conditions at the nesting site, and geographic location of populations of this species. Within North America, populations of H. rubicundus expressing social and solitary behavior belong to different genetic lineages. Sociality is also correlated with at least one environmental variable used in this study. Taken together, the results support the predictions for genetic control of sociality, but they are still consistent with social behavior at some level being determined by the environmental conditions at the nesting site.

Phylogeny of Halictidae with an emphasis on endemic African Halictinae

“…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).…”

Phylogeography and historical demography of the neotropical stingless beeMelipona quadrifasciata(Hymenoptera, Apidae): incongruence between morphology and mitochondrial DNA

“…Some molecular population genetics studies have been conducted with bees (Tanaka et al, 2001;Soucy and Danforth, 2002;Dick et al, 2004;Cruz et al, 2006;Quezada-Euán et al, 2007;Kraus et al, 2008). However, none of the studies have applied coalescent and more recent phylogeographic methods.…”

Survival and productivity benefits to social nesting in the sweat bee Megalopta genalis (Hymenoptera: Halictidae)

“…The massprovisioning bee family Halictidae is a key taxon for understanding social evolution. Halictids exhibit multiple evolutionary origins and losses of eusociality, communality, brood parasitism, and solitary nesting (Michener 1974(Michener , 1990Danforth and Eickwort 1997;Wcislo and Danforth 1997;Wcislo 1997Wcislo , 2000Danforth 2002;Soucy and Danforth 2002;Coelho 2002;Richards et al 2003;Danforth et al 2004). In fact, AFR may be greater in mass provisioners.…”