Ashton Cuckoo Bumble Bee, Bombus Ashtoni

Excerpted from Bumble Bees of Wisconsin

Ashton Cuckoo Bumble Bee, Bombus Ashtoni The Ashton Cuckoo Bumble Bee is very rare and is declining rapidly. Historically it is known from the eastern and midwestern U.S. As of 2015, it is only known from seven sites in North America. Wisconsin has a handful of historic observation records from northern and northeastern counties. The species was last reported in Wisconsin in 1979.

The Ashton Cuckoo Bumble Bee is a nest parasite of the Rusty Patched Bumble Bee and the Yellow Banded Bumble Bee.

  Physical Description

Hair medium and even. Thorax yellow, with a straight or “T” shaped band of black hair between the wings. First abdominal segment fully yellow, with the second segment yellow and usually containing a patch of orange or rusty-brown hair. Unlike B. griseocollis, this patch is entirely surrounded by yellow hairs. Queens often without the rusty-patch, making the second abdominal segment entirely yellow. Males have similar color patterns to workers, but occasionally with more brown hair on the second abdominal segment. Males also lack corbiculae, or the flattened midleg of the hind leg used for transporting pollen.


Ashton Cuckoo Bumble Bees lay their eggs in the colonies of other species to raise their young. Only new, mated queens overwinter, emerging from diapause (a form of hibernation) in the spring. New queens kill or subdue the queen of a host colony and lay eggs, which the host colony raises. The resulting cuckoo bee offspring are all queens or males. New queens mate and enter diapause.

  Activity Period

Ashton Cuckoo Bumble Bee, Bombus Ashtoni activity period Historically, the majority of observation records in Wisconsin took place in August. Earliest records were in April and latest in October.


Ashton Cuckoo Bumble Bee, Bombus Ashtoni graphic Habitat types are variable, and likely depend on host species. Overwintering sites are unknown.

  Feeding Habits

Ashton Cuckoo Bumble Bees do not have the ability to collect pollen.

 Buzz Pollination
 Slo-Mo Footage of a Bumble Bee Dislodging Pollen
 Look Inside a Bumblebee Nest
 How to Build a Bumble Bee House
 Development of Colony and Nest in the Bumblebee

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