Bombus citrinus
In 3 days ~10% in a week ~30%
Bombus citrinus is a species of bumblebee known commonly as the lemon cuckoo bumblebee due to its lemon-yellow color. It is native to eastern North America. This is a cuckoo bumblebee, one that invades the colonies of other bumblebees, kills the resident queen, and takes control over the population of workers inside. Host bees for this species include the common eastern bumblebee (Bombus impatiens) and the half-black bumblebee (B. vagans).
Before the queen invades a nest she forages on various plants, such as asters, thistles, snakeroots, blazing-stars, mountain-mints, and goldenrods. Bombus citrinus belongs to the parasitic Bombus subgenus Psithyrus. A previous classification had Psithyrus listed as its own genus, and so this species used to be identified as Psithyrus citrinus. Members of Psithyrus are distinguished from other Bombus based on an abdomen with thick tergites, a long stinger, enlarged mandibles, loss of corbiculae, no worker castes, and a reduction in wax glands and its production; all of these features are associated with being inquiline parasites that replace host queens. Of the other species within this subgenera it is most closely related to Bombus... Wikipedia →
| # | Park | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Great Smoky Mountains National Park | 🇺🇸 United States |
More parks will be added in future updates.
| # | City | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Minneapolis [Saint Paul] | 🇺🇸 United States | |
| 2 | Philadelphia | 🇺🇸 United States | |
| 3 | New York City | 🇺🇸 United States | |
| 4 | Detroit | 🇺🇸 United States | |
| 5 | Toronto | 🇨🇦 Canada | |
| 6 | Washington | 🇺🇸 United States | |
| 7 | Montreal | 🇨🇦 Canada | |
| 8 | Baltimore | 🇺🇸 United States | |
| 9 | Chicago | 🇺🇸 United States |
Rare
Under 5% of wildlife watchers report a Lemon Cuckoo Bumble Bee sighting in Great Smoky Mountains National Park on a given day, based on 10 verified sightings from GBIF citizen-science data from 2019 to 2026. It is the 513th most-seen of the 822 insects we can rate there. Over three days the chance rises to about 10%, and over a week to about 30%, if each day is a fresh chance.
July and October–November
In those months about 10% of wildlife watchers report a Lemon Cuckoo Bumble Bee in Great Smoky Mountains National Park on a given day, against under 5% in August–September and December–June, the lowest months.
Between 1 and 4 pm
Across all the parks we cover, that three-hour window holds the most Lemon Cuckoo Bumble Bee sightings with a recorded time, and nearly all of them come between 6 am and 6 pm: it is a daytime animal.
Only Great Smoky Mountains National Park, in our data
Great Smoky Mountains National Park is the only park on Wallace's Line with enough records to rate Lemon Cuckoo Bumble Bee sightings: under 5% of wildlife watchers there report one on a given day.
Same genus: Bombus
The closest relatives of the Lemon Cuckoo Bumble Bee that you can see in Great Smoky Mountains National Park (genus Bombus, Bumble Bees) are Common Eastern Bumble Bee (about 40%), Two-Spotted Bumble Bee (about 10%) and Brown-Belted Bumble Bee (about 10%), with each one's daily chance of a sighting.
GBIF citizen-science records
It is estimated from how often the Lemon Cuckoo Bumble Bee is recorded against all the insects logged in Great Smoky Mountains National Park (10 verified sightings from 2019 to 2026), calibrated against known sighting rates. Figures are rounded to the nearest 10% because citizen-science data supports honest approximations, not decimals, and months with records from fewer than five people show "—". How it works.
