Gypsy Cuckoo Bumble Bee

(Bombus bohemicus)

Status: Endangered (COSEWIC 2014 , ESA 2015)

Table of Contents:

Species Identification
Diet
Habitat and Range
Biology and Behaviour
Threats/Reasons for Being Endangered
Conservation and Recovery Strategies
How You Can Help

Species Identification:

The Gypsy Cuckoo Bumble Bee is a medium-sized bee of about 12-18 mm in length. Both males and females have a black head and black and yellow striped body that is mostly black and ends in white or pale yellow. Unlike most bees, they do not have “pollen baskets” on their hind legs since they are a parasite bee that takes over existing colonies from other bee species.

Diet:

The Gypsy Cuckoo Bumble Bee forages for pollen and nectar on a wide variety of native and non-native plant species. Since they are a parasitic bee, they also take pollen and nectar from other bee colonies like the Yellow-banded Bumble Bee and the Rusty-patched Bumble Bee.

Map taken from Government of Canada: https://publications.gc.ca/collections/collection_2014/ec/CW69-14-692-2014-eng.pdf

Habitat and Range:

The Gypsy Cuckoo Bumble Bee is found across much of Europe, Asia and North America. They are considered to be abundant in much of Europe where their host species are also abundant. They were historically recorded in all 10 provinces as well as the Northwest Territories and the Yukon, but in the last decade they have only been found in Ontario, Quebec, and Nova Scotia. They were historically found throughout much of Southern Ontario, but they have not been recorded in the province since 2008 at Pinery Provincial Park near Grand Bend. The Gypsy Cuckoo Bumble Bee is thought to be extirpated from The Land Between. The host populations of the Gypsy Cuckoo Bumble Bee have declined dramatically recently, which is most likely the main reason for the Gypsy Cuckoo Bumble Bees decline. The Rusty-patched Bumble Bee has not been seen in Ontario since 2009, and the Yellow-banded Bumble Bee is listed as Special Concern.

The Gypsy Cuckoo Bumble Bee generally lives where their host species lives. They live in a variety of habitats like open meadows, agricultural fields, boreal forests, and woodlands. Their hosts will generally make their nests in old underground rodent burrows, and while their overwintering habits are unknown, they are suspected to hibernate underground.

Biology and Behaviour:

The Gypsy Cuckoo Bumble Bee is a parasite of Rusty-patched and Yellow-banded Bumble Bees. In the spring, a female Gypsy Cuckoo Bumble Bee takes over a nest by killing or forcing the host queen out. The worker bees of the host colony then feed and take care of the Gypsy Cuckoo Bumble Bee female and her young through chemical cues. Gypsy Cuckoo Bumble Bee eggs will hatch after four days and pupate in about two weeks. In another two weeks, the pupae will be adults. Once the adults mate, the males will die and the successful females will overwinter until emerging in the spring and finding a new host nest.

The Gypsy Cuckoo Bumble Bee is capable of living in a diverse range of habitats from meadows and agricultural fields to woodlands. Because it is a parasitic bumble bee and is dependent on its host species to raise and care for its young, it must live where one or both of its hosts live. Gypsy Cuckoos tend to forage in or near woodland areas, in fields and grasslands, and along the sides of the roads. The Gypsy Cuckoo Bumble Bee may overwinter in rotting logs, leaf litter, soil burrows, or garden compost. Only females that have mated will overwinter, while the rest of the females and all of the males die at the end of the season.

Threats/ Reasons for being at Risk:

1. Decline of host species: The most significant threat to the Gypsy Cuckoo Bumble Bee is the population decline of its host species- the Rusty-patched Bumble Bee (last seen in Ontario in 2009) and the Yellow-banded Bumble Bee (Special Concern in Ontario). The range of the Yellow-banded Bumble Bee in southern Ontario has decreased significantly due to habitat loss and pesticide use, leaving the Gypsy Cuckoo Bumble Bee with no home or hosts in which to survive. The Gypsy Cuckoo cannot survive on their own by making their own nests and collecting their own food.

2. Pathogen spillover: The introduction of diseases from domestic or managed bee populations, which are used for agricultural purposes, is believed to be a significant contributing factor to the population declines of the host species. Diseases from domestic bees spread to wild populations of Yellow-banded and Rusty-patched Bumble Bees, further leading to their decline.

3. Habitat loss, fragmentation and degradation: Although the Gypsy Cuckoo Bumble Bee does not have specific habitat requirements, it does require mating, foraging, nesting and overwintering habitat all within a relatively close range of each other. However, human development has contributed to habitat degradation and fragmentation which separate these habitats from each other, or contributes to losses of certain habitat requirements.

4. Invasive/non-native species: The introduction of the Common Eastern Bumble Bee that was introduced to help with pollination in Canada has ended up out-competing native bee species like the hosts of the Gypsy Cuckoo Bumble Bee. The Common Eastern Bumble Bee is also susceptible to diseases that can spread to the Yellow-banded and Rusty-patched Bumble Bee species.

Conservation and recovery strategies:

The first step to Gypsy Cuckoo Bumble Bee recovery is to recover their host species- the Yellow-banded Bumble Bee and the Rusty-patched Bumble Bee. This means tackling issues like habitat loss and degradation, pesticide and fertilizer use, diseases from domestic bees, and climate change. Currently, researchers are trying to recover Yellow-banded populations through breeding and community science programs. Since the Rusty-patched Bumble Bee may be extirpated from Ontario, it will take a great deal more work to re-introduce them, but similar methods to the Yellow-banded Bumble Bee can be used. Another important part of recovery is to increase research into finding current locations of Gypsy Cuckoo Bumble Bees, since not many have been found in the past few years in Canada.

How can you help?

Identify and record Gypsy Cuckoo Bumble Bees and submit observations to The Land Between online and/or to iNaturalist. Your observations help scientists monitor and track Gypsy Cuckoo Bumble Bee populations, and are especially important since there have not been significant sightings in Ontario for years.
Plant a pollinator-friendly garden with a variety of native flowers that bloom from early spring to late fall so that bees have a food source throughout their entire life cycle.
Gypsy Cuckoo Bumble Bee queens feed on dandelion flowers in early spring when they emerge from their overwintering sites, as they are one of the only sources of food available at that time. Consider leaving dandelions on your property until after other flowers are in bloom so bees have as much access to food as possible.
Consider leaving old rodent burrows on your property intact. These burrows can be used as nests by the Gypsy Cuckoo Bumble Bee, and other bee species. In exchange for your hospitality, the bees will provide you with pollinating services of your garden!

Additional Resources:

Government of Ontario Gypsy Cuckoo Bumble Bee page
COSEWIC 2014 Report and Assessment on the Gypsy Cuckoo Bumble Bee

Sources:

Government of Ontario. 2016. Gypsy Cuckoo Bumble Bee. Retrieved from: https://www.ontario.ca/page/gypsy-cuckoo-bumble-bee

COSEWIC. 2014. COSEWIC assessment and status report on the Gypsy Cuckoo Bumble Bombus bohemicus in Canada. Committee on the Status of Endangered Wildlife in Canada. Ottawa. ix + 56 pp. https://www.sararegistry.gc.ca/virtual_sara/files/cosewic/sr_Gypsy%20Cuckoo%20Bumble%20Bee_2014_e.pdf