Images

East Coast, West Coast, this parasitic species, Coelioxys octodentata occurs throughout the United States, almost completely filling the country with records and stopping at the border for some reason. How closely related are the specimens on the Pacific edge versus the Atlantic? Unknown, but for now they are just one species. Red legs are classic C.

A nest parasite, this time a male. Coelioxys octodentata is a counterpart to the more commonly found C. sayi. I associate this species with drier and perhaps sandier locations, perhaps as the nest parasite of things like Megachile brevis. Note the characteristic teeth sticking out of the rear of this bee.

A nest parasite, this time a male. Coelioxys octodentata is a counterpart to the more commonly found C. sayi. I associate this species with drier and perhaps sandier locations, perhaps as the nest parasite of things like Megachile brevis. Note the characteristic teeth sticking out of the rear of this bee.

East Coast, West Coast, this parasitic species, Coelioxys octodentata occurs throughout the United States, almost completely filling the country with records and stopping at the border for some reason. How closely related are the specimens on the Pacific edge versus the Atlantic? Unknown, but for now they are just one species. Red legs are classic C.

An invader of other bees nests, this is Coelioxys porterae, found, in this case from Acadia National Park in Maine. I can't recall which species of Megachile (leaf cutting bees) this species parasitizes us but there are plenty of options in the park. This is a male, and as with almost all males it has all kinds of pointy projections on its rear end.

An invader of other bees nests, this is Coelioxys porterae, found, in this case from Acadia National Park in Maine. I can't recall which species of Megachile (leaf cutting bees) this species parasitizes us but there are plenty of options in the park. This is a male, and as with almost all males it has all kinds of pointy projections on its rear end.

Coelioxys porterae, male, Maine, Acadia National Park

Another Coelioxys nest parasite bee from the Adirondack Mountains of New York. This one is a nest parasite of big Leaf Cutters like Megachile latimanus. Here are shots of a male and a female.

Another Coelioxys nest parasite bee from the Adirondack Mountains of New York. This one is a nest parasite of big Leaf Cutters like Megachile latimanus. Here are shots of a male and a female.

Another Coelioxys nest parasite bee from the Adirondack Mountains of New York. This one is a nest parasite of big Leaf Cutters like Megachile latimanus. Here are shots of a male and a female.

Another Coelioxys nest parasite bee from the Adirondack Mountains of New York. This one is a nest parasite of big Leaf Cutters like Megachile latimanus. Here are shots of a male and a female.

Another Coelioxys nest parasite bee from the Adirondack Mountains of New York. This one is a nest parasite of big Leaf Cutters like Megachile latimanus. Here are shots of a male and a female.

The most common of the Coelioxys nest parasites in the mid-atlantic region. This is C. sayi, in this case, a male and simply a mating machine, not involved in nest construction. Check out the multi-pointed rear end. I am unaware of what use this is, but most of the Coelioxys males have some variant of this unusual pattern. Photographed by Ashleigh Jaoobs.

The most common Coelioxys in the East. C. sayi is a nest parasite, slipping into the nests of leaf cutters like Megachile mendica and kin and dropping an egg into the wall of their nests. In the female, like this one, the edge of the clypeus is slightly indented (hard to see). Now you know.

The most common Coelioxys in the East. This is C. sayi. Now, C. sayi is a nest parasite (like all Coelioxys) and it likes to drop its eggs in the nest of what is usually the most common Leaf Cutter in the East Megachile mendica.

The most common Coelioxys in the East. C. sayi is a nest parasite, slipping into the nests of leaf cutters like Megachile mendica and kin and dropping an egg into the wall of their nests. In the female, like this one, the edge of the clypeus is slightly indented (hard to see). Now you know.

The most common Coelioxys in the East. C. sayi is a nest parasite, slipping into the nests of leaf cutters like Megachile mendica and kin and dropping an egg into the wall of their nests. In the female, like this one, the edge of the clypeus is slightly indented (hard to see). Now you know.

The most common Coelioxys in the East. This is C. sayi. Now, C. sayi is a nest parasite (like all Coelioxys) and it likes to drop its eggs in the nest of what is usually the most common Leaf Cutter in the East Megachile mendica.

The most common Coelioxys in the East. This is C. sayi. Now, C. sayi is a nest parasite (like all Coelioxys) and it likes to drop its eggs in the nest of what is usually the most common Leaf Cutter in the East Megachile mendica.

The most common Coelioxys in the East. This is C. sayi. Now, C. sayi is a nest parasite (like all Coelioxys) and it likes to drop its eggs in the nest of what is usually the most common Leaf Cutter in the East Megachile mendica.

This is the male of a species that parasitizes Megachile (leaf cutter nests) by laying their eggs in the nest of the host, after which the young Coelioxys sodalis emerges and kills the host larvae and consumes the pollen and nectar of the host's young. About 20% of all bees work on this model.