>500 spp. in 14 genera of 9 tribes in our area, ~1,230 spp. (of which >700 are in Nomada
) in 32 genera of 10 tribes worldwide(1)
All lack a pollen-transporting apparatus and many are strikingly wasp-like in appearance(2)
. The apex of the metasoma of females is modified for placing their eggs within host nests.
worldwide, most diverse in NA; all the tribes are represented in the New World, but only 5 in the Old World, where they are most diverse in the Palaearctic, rather poorly represented in the Subsaharan Africa (65 spp.), SE Asia (<30 spp.) and especially Australasia(1)
Many Nomada emerge very early in spring whereas other Nomada and many species in tribes such as Epeolini fly in summer and fall.
All are cleptoparasites of other bees.
All are parasites in the nests of other bees.(2)
They enter the nests of their hosts when the host is absent and lay their eggs into the wall of the cell.(3)
Females produce many more eggs than their hosts and these are very small.(2)
Various other tribes including Melectini, Rhathymini, Ericrocidini, Osirini, and Protepeolini, have been associated with Nomadinae in the past, whereas evidence from life history studies by Rozen support multiple independent origins of these.
Recent molecular phylogenies proposing a single origin of cleptoparasitism for most apid cleptoparasites (i.e. for inclusion of all nomadine and most apine cleptoparasites in a single clade) have strong clade support only by measures such as Bayesian PP that are well known to be inflated, and support is lacking by more conservative measures such as the parsimony jackknife.
Many papers by Rozen in American Museum Novitates
Papers by Rozen in American Museum Novitates are publicly accessible online