Corbiculate apines are a monophyletic group that includes all bees that form colonies (and some of their parasites) and have concave "baskets" on hindlegs for carrying pollen and nesting material (Dressier 1982a; Kimsey 1987; Michener 1990; Prentice 1991; Cameron 1993; Roig-Alsina and Michener 1993).
A low number of alleles at a sex-determining locus, relative to other corbiculate apines, would lead to more frequent homozygosity and production of diploid males in euglossines, as would inbreeding (Duchateau et al.
Little to moderate polymorphism, averaging [less than] 10%, depending on taxa and techniques, has been found in corbiculate apines - Apini, Meliponini, and Bombini.