Yellowish Cuckoo Bumble Bee

bombus flavidus

The Yellowish Cuckoo Bumble Bee (Bombus flavidus) is a fascinating and stealthy inhabitant of boreal and montane ecosystems. Unlike typical bumble bees that laboriously gather pollen to provision their nests, this species lives as an obligate social parasite, or 'cuckoo.' Females are specialized infiltrators that seek out the established colonies of other bumble bee species, relying on the host workers to rear their young. This unique lifestyle completely bypasses the need to build a nest or forage for larval food, highlighting a remarkable evolutionary divergence within the bee world. Because of their reliance on host populations, the presence of the Yellowish Cuckoo Bumble Bee is a strong indicator of a healthy, thriving ecosystem capable of supporting diverse bee communities. Their distinct behaviors and life cycle make them a captivating subject for both casual observers and entomologists.

Habitat: Found in boreal forests, taiga, and high-elevation alpine meadows, strictly following the distribution of its specific bumble bee host species.

Appearance

Bombus flavidus can be distinguished from non-parasitic bumble bees primarily by the distinct lack of corbiculae (pollen baskets) on the hind legs of females; instead, their hind legs are rounded, convex, and densely hairy. They generally feature a relatively shaggy coat of pale yellowish hair on the thorax and abdomen, often interrupted by a darker band of black hairs between the wings and on the face. Their bodies appear slightly more robust with a thicker, harder exoskeleton, which serves as armor, and their wings often have a subtle dark tint. They lack the characteristic worker caste, so any encountered individual will either be a large reproductive female or a male.

KingdomAnimaliaPhylumArthropodaClassInsectaOrderHymenopteraFamilyApidaeGenusBombus

Yellowish Cuckoo Bumble Bee

Interesting facts

Because they never need to collect food for their young, female cuckoo bumble bees completely lack the pollen baskets found on the legs of typical bumble bees.

Cuckoo bumble bees do not produce a worker caste; every egg laid by the intruding female is destined to become a reproductive male or a new queen.

To survive the hostile takeover of a colony, they have evolved heavily armored exoskeletons that protect them from the stings of defending workers.

When sneaking into a host nest, a female may hide in the nest debris for days, absorbing the colony's unique scent to avoid being attacked.

Special abilities

Females take over the nests of other bumble bee species, subjugating or killing the resident queen and forcing host workers to raise her offspring.

Possesses an exceptionally thick and hardened cuticle designed to protect the bee from stings and bites during hostile nest takeovers.

Capable of mimicking the specific pheromonal scent of the host colony to avoid detection and reduce aggression from defending workers.

Measurements & details

Length: 1-2 cm
Wingspan: 2-4 cm
Weight: 0.0001-0.0004 kg
Lifespan: 0-1 years
Top Speed: 15 km/h
Clutch Size: 10-50
Incubation: 4-6 days

Diet & Feeding

Adults sustain themselves purely on flower nectar for energy, while their larvae are fed a mixture of nectar and pollen gathered entirely by the workers of their host colony.

Age differences: Larvae consume a protein-rich diet of pollen and nectar provided by host workers, whereas adults consume strictly nectar for immediate flight energy.

Primary Foods

Nectar from Asteraceae
Fireweed nectar
Goldenrod nectar
Host-gathered pollen (larvae)

Foraging Method

Foraging

Ecological connections

parasite

Western Bumble Bee

Bombus occidentalis

Infiltrates nests to use workers for rearing offspring.

mutualism

Fireweed

Chamerion angustifolium

Adults forage on nectar, providing incidental pollination.

eaten by

Goldenrod Crab Spider

Misumena vatia

Ambushed and eaten while foraging on flowers.

Traits

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Also known as

No aliases listed yet.

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Safety

Danger

1/5 · Very low

No special safety notes yet.

Frequently Asked Questions

How to identify Yellowish Cuckoo Bumble Bee?

The easiest way to identify Yellowish Cuckoo Bumble Bee is to use the Snappit nature identifier app.

How long is Yellowish Cuckoo Bumble Bee?

1-2 cm

What is Yellowish Cuckoo Bumble Bee's wingspan?

2-4 cm

How much does Yellowish Cuckoo Bumble Bee weigh?

0.0001-0.0004 kg

How long does Yellowish Cuckoo Bumble Bee live?

0-1 years

How fast can Yellowish Cuckoo Bumble Bee move?

15 km/h

What does Yellowish Cuckoo Bumble Bee eat?

Adults sustain themselves purely on flower nectar for energy, while their larvae are fed a mixture of nectar and pollen gathered entirely by the workers of their host colony.

Where is Yellowish Cuckoo Bumble Bee usually found?

Found in boreal forests, taiga, and high-elevation alpine meadows, strictly following the distribution of its specific bumble bee host species.