• Family: Apidae
• Approximate # species in region: 16
• Common name: longhorn-cuckoo bees

Some of our meanest-looking bees, Triepeolus are cleptoparasites of longhorn bees (Eucerini). They are typically distinctly banded in white, black, and red, relatively hairless and found in the summer months when eucerines are active. Triepeolus females lay eggs in the open brood cells of longhorn bees. The eggs hatch into first instar larvae that kill the host egg with their large mandibles. The larva develops on the host pollen provision. Some of the relationships between Triepeolus and their hosts are well known and documented, as is the case with T. remigatus and Peponapis pruinosa, while others are only presumed relationships based on limited knowledge of host nesting biology.

Telling Triepeolus apart from their close relatives Epeolus at the genus level can be tough in the field – we recommend learning the color patterns of common members of both genera to better recognize some of the more distinctive species. Our most common Triepeolus average a bit larger than Epeolus and are more apt to turn up in summer gardens (with the exception of the unmistakeable E. bifasciatus), a favorite hangout of their eucerine hosts .

Regional Species List: