We have been seeing this curious insect every year in February and March in our spring wildflowers.
It regularly visits the desert marigolds.
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?