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After doing Bug of the Week for so many years, it can be difficult to find something new. This week I was lucky.


Although it looks quite a bit like a sand wasp, this is a new kind of cuckoo bee. It might be Triepeolus sp. (like this one).


Look at the tongue (proboscis) that it using to suck up nectar.


We have seen another cuckoo bee in our yard before, Xeromelecta californica (previous post).

Named after cuckoo birds, cuckoo bees lay their eggs in the nests of other kinds of bees or sometimes wasps, depending on the species. They don't build their own nests and lack pollen baskets for collecting pollen. It's not a warm and fuzzy lifestyle, but that's nature for you.

We have been seeing this curious insect every year in February and March in our spring wildflowers.

cuckoo-bee-2015(February 18, 2015)

It regularly visits the desert marigolds.

2009-cuckoo-bee-xeromecta-californica-male(March 4, 2009)

Although it looks like a wasp or maybe a flower fly, it is a bee. In fact, it is a cuckoo bee, Xeromelecta californica.

What is a cuckoo bee?

Instead of making a nest and gathering pollen of their own, cuckoo bees sneak into the nests made and provisioned by digger bees (Anthophora sp.. especially Anthrophora urbana.) The females kill the eggs the mother digger bee laid and lay their own eggs on the food instead. The cuckoo bees then fly away and the nest eventually produces cuckoo bees rather than digger bees.

Ah, the drama that unfolds in one small suburban yard.

Have you ever discovered a cuckoo bee? What kinds are found where you live?