The Suckley’s cuckoo bumble bee has a unique life cycle. Like cuckoo birds, they lay their eggs in the nests of other species instead of rearing their own young.
True bumblebees live in colonies with workers and queens. But cuckoo bumble bees have a different strategy for survival. Males die after mating and females hibernate all winter in logs, stumps or holes in the ground. They emerge later in the spring than other bees, find a hive, kill the queen and take over the workers. Pheromones convince the worker bees to raise the cuckoo eggs and larvae as their own.
Since they don’t feed their own young, cuckoo bumble bees don’t have pollen-carrying baskets on their hind legs the way other bees do. But they still practice something called “buzz pollination,” where they grab a flower and shake it to release the pollen — useful for both the flowers and the bees.
This species was once found throughout western Canada and the western United States, but the last sighting of one in the U.S. was in 2016. Native bee populations are plummeting. Pesticides, habitat loss, climate change, and diseases all play a role, according to the Xerces Society for Invertebrate Conservation.
It’s possible cuckoo bumble bees still exist in isolated places in the Rocky Mountains or the Sierra Nevada. They’re on the “red list” for endangered species published by the International Union for Conservation of Nature, and are now being considered for protection under the Endangered Species Act.
This Earth Note was written by Melissa Sevigny and produced by KNAU and the Sustainable Communities Program at Northern Arizona University.
