Variable Cuckoo Bumble Bee
If you are familiar with the cuckoo bird, you may be able to guess what’s special about the cuckoo bumblebee?
That’s right, they leave their young in a nest for another parent to take care of.
For the variable cuckoo bumble bee, they have lost their ability to collect or store pollen and are unable to rear their own young. They typically invade the home of the American bumble bee and force them to care for the young.
Workers from the host colonies continue to gather pollen and nectar to provision the cuckoo’s larvae, producing new reproductive females and males.
Cuckoo bumblebees, from the subgenus Psithyrus, originating from the Greek word "psithyros," which means "whispering" or "twittering," referring to the quiet, almost secretive nature of the cuckoo bumblebee species, are clever infiltrators of the insect world
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. The American bumble bee, has experienced an 89% decline in observations over the past 20 years. Of the 46 species of bumble bees in North America, 12 are in decline and classified as vulnerable, endangered, or critically endangered.
Where Does the Variable Cuckoo Bumble Bee Live?
Most records 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.
It used to live across the eastern half of the United States as far southwest as Arizona and as far northeast as New Hampshire.
The bee tends to rely on food from Aster, Bidens, and Echinacea.
Why is the Variable Cuckoo Bumble Bee at Risk?
The most recent observations of the variable cuckoo bumble bee from 1995, 1998, and 1999 represent 17 observations from Florida, four observations in Mississippi, four observations in Nebraska , and three observations from Missouri.
Like most bumble bees, this species faces threats from multiple sources including pesticides, habitat loss or degradation, climate change, and diseases that can be introduced by non-native bee species.
States across the Midwest and the Northeast have lost as much as 50% of their perennial grasslands and now have very few or no recent observations of the American bumble bee.
Non-native honey bees and domesticated bumble bees introduced for honey production and pollination have spread diseases such as Nosema bombi to the variable cuckoo bumble bee’s host.
The variable cuckoo bumble bee and its host have lost habitat through the destruction, fragmentation, and modification of habitat by intensive agriculture, livestock grazing, and widespread pesticide use that limits access to floral resources, lowers floral richness, and limits nesting sites across its range.
