On the right a Cuckoo Bee {Nomada leucophthalma} is waiting to enter the nest burrow of a Mining Bee {Andrena clarkella}, which is digging on the left. The cuckoo bee is cleptoparasitic, laying its eggs in nests of other bees in order that their parasitic larvae can feed on the food originally intentended for the host larvae. Peak District National Park, Derbyshire, UK. April.