Cuckoo Bee

Cuckoo bees are a behavioral category encompassing approximately 15% of all bee species worldwide (~3,000 of the ~20,000 known bee species), distributed across at least 4 bee families (Apidae, Megachilidae, Halictidae, and Andrenidae) where the kleptoparasitic life history has independently evolved. Nomada panzeri is one of the most familiar cuckoo bees in Europe and North America. The strategy: a female cuckoo bee finds the underground nest of a host bee (typically a Andrena solitary mining bee for Nomada), waits for the host female to leave on a foraging trip, enters the nest, and lays one or more eggs in or near the host's pollen-and-nectar provisioned cells. The cuckoo bee egg hatches before the host's egg (cuckoo bee eggs typically have shorter development time); the cuckoo larva uses sharp mandibles to kill the host's egg or first-instar larva, then consumes the pollen-and-nectar provisions intended for the host. The cuckoo bee adult emerges from the host's nest the following spring. Because cuckoo bees do not gather their own pollen, they lack the dense pollen-collecting hairs (scopae or corbiculae) that characterize true pollen-foraging bees. They are typically smaller, slimmer, and wasp-like in appearance — frequently mistaken for small wasps. The kleptoparasitic strategy is the bee equivalent of the cuckoo BIRD's brood parasitism, and the convergent evolution is one of the most-cited examples of behavioral parallelism across vertebrates and invertebrates. Cuckoo bees are widespread and important participants in bee community dynamics, but their populations depend entirely on the populations of their host species — making them a useful indicator of solitary bee community health.