The variable cuckoo bumble bee belongs to a subgenus of bumble bee species that have lost their ability to collect or store pollen and are unable to rear their own young. Instead, they rely on host species that they parasitize. Variable cuckoo bumble bees will invade the nests of host species and take control, forcing the inhabitants to raise and care for their offspring. As such, the status of this species is closely linked to that of its preferred host species, the American bumble bee. The recent population decline of its single known host species is cause for concern about the status of variable cuckoo bumble, which is one of the rarest bumble bee species in North America. 

Occurrence records for variable cuckoo bumble bees are concentrated in the eastern temperate forest and great plains regions of North America, but the species has only been confirmed a handful of times in recent decades. The species relies on an assortment of floral groups for food, such as Aster, Bidens, and Echinacea. Like most bumble bees, this species faces threats from multiple sources including pesticides, habitat loss or degradation, climate change climate change
Climate change includes both global warming driven by human-induced emissions of greenhouse gases and the resulting large-scale shifts in weather patterns. Though there have been previous periods of climatic change, since the mid-20th century humans have had an unprecedented impact on Earth's climate system and caused change on a global scale.

Learn more about climate change , and diseases that can be introduced by non-native bee species. Given the rarity of the species and its dependency on its host species, which is in decline, conservation of variable cuckoo bumble bee will need to rely heavily on the conservation of its host. 

The U.S. Fish and Wildlife Service supports various initiatives to increase high quality pollinator habitat for native bumble bee species, including through the New England Pollinator Partnership. This collaborative effort with the USDA Natural Resources Conservation Service and the Xerces Society for Invertebrate Conservation focuses on working with farmers and other landowners to promote pollinator conservation on their lands.