Crawlies with Cri: Wide-belted dark bee (Stelis laticincta)

This week’s crawly reminds us once again that nature never runs out of ideas. Meet the wide-belted dark bee (Stelis laticincta). Yep. This bitty flitter is a bee, not a wasp.
Even though this species of dark bee is brightly colored, at just under one-quarter of an inch, they are tricky to spot.
Most dark bees (Genus Stelis) are, in fact, dark. Only a few of the 65 species in the genus have bold markings.

Wide-belted dark bee (Stelis laticincta)

Their dark color serves as camo because they are kleptoparasites of other leaf cutter bees, most likely Megachile.
A kleptoparasite differs from a parasite (i.e. fleas and ticks) in that they don’t harm the host, but steal the host’s food stores.
Most of the other dark bees are so good at resembling their host bees, that some are even dark blue to mimic blue orchard bees.
The wide-belteds just have to do their own thing though and look wasp-like. All the bee species the wide-belted kleptoparasitize are dark in color.
Wide-belted also have a rounded, or “stout” as the internet describes them, body shape. Most of the other dark bee species share this “chonky” shape.
Wide-belted can afford to rock the sleek, hairless “wasp look” because the females don’t need to gather pollen. They just visit flowers to drink nectar. Some pollen will stick to their very fine leg hairs, so they are incidental pollinators, but don’t pack on the pollen like most bee species.
Female wide-belted don’t gather pollen because they don’t have to. They’ll wait for a female host bee to create an egg cell, lay an egg and pack in pollen food provisions, then sneak in while the other female is out foraging and lay one of their eggs in the cell.
Either the wide-belted bee will destroy the host’s egg before laying her egg, or the wide-belted egg will hatch first and the larvae will destroy the host egg, then chow down on the pollen provisions.
It may seem like kleptoparasitic bees would be harmful to the overall population of the host bees, but there are over 65 species of dark bees in North America, and many more other kleptoparasitic bee species in other families and genuses. Nature has a way of sorting it all out so there is room for host species and kleptoparasites.
While we think of honeybees or bumblebees when we think of bees, there’s a huge variety of bees out and about in our area, all quite unique.
Dark bees are in the Tribe Anthidiini which consists of several fun species like the wool carder bee, which we’ve met as well as resin bees and even pebble bees. Now there’s a unique bee name.
We may get to meet pebble bees more in depth in the future, but a quick fun fact – they get their name from their use of teeny gravels to build their nests.
Wide-belted dark bees are on the wing from July – September, so look twice at tiny wasp-like critters drinking up nectar from flowers in your yard. If they look “chonky” you just might be seeing a wide-belted.