Cleptoparasitism

Definition

A cleptoparasitic bee builds no nest and collects no pollen. The female finds a host's provisioned cell, lays her egg in it, and her larva kills the host's egg or larva — many have specialised sickle-shaped jaws in the first instar for exactly this — and consumes the pollen store. The strategy has evolved independently many times, and somewhere between a tenth and a fifth of the world's roughly 20,000 bee species live this way. Cleptoparasites lack pollen-carrying structures entirely, which is their most reliable identifying feature.

Where the word gets used loosely

Frequently read as a pest problem to be controlled. It is the opposite signal: a cuckoo bee needs its host not merely present but abundant, so their occurrence indicates a healthy host population. They decline faster than their hosts and recover more slowly, which makes them an early warning rather than a late symptom.

Bee records that discuss this

• Cuckoo beesBees that build no nest, gather no pollen and feed no young of their own. A cuckoo bee female finds another bee's provisioned cell, slips in, and lays her egg on somebody else's pollen store; her larva then kills the host's egg or larva and eats the food it was left. It sounds like a marginal aberration and it is not — cleptoparasitism has evolved repeatedly across the order, and a healthy bee fauna is expected to contain a substantial number of these.