What If Gone

Species → Rusty Patched Bumble Bee

Rusty Patched Bumble Bee

Bombus affinis

an 87–90% decline since the 1990s; gone from 70–90% of its historic…
Extinction risk Critically Endangered
PollinatorAgriculturalCatastrophic decline
Rusty Patched Bumble Bee (Bombus affinis)
Photo: USFWS Midwest Region, Wikimedia Commons (CC BY 2.0)

What if it disappeared?

Impact Low
With every flower visit

The rusty patched bumble bee, like other bumble bees, vibrates its flight muscles against the anther to release pollen from buzz-pollinated flowers (tomato, blueberry, cranberry, eggplant) — a technique, "buzz pollination," that the honey bee is physically incapable of performing.

Documented
Detail

Cooley, H. & Vallejo-Marín, M. (2021). Buzz-Pollinated Crops: A Global Review and Meta-analysis of the Effects of Supplemental Bee Pollination in Tomato. Journal of Economic Entomology, 114(2), 505–519.

The meta-analysis combines 21 experiments from 24 studies worldwide and confirms that supplemental bumble bee pollination increases tomato yield and quality compared to self-pollination alone or honey bee pollination alone. About 95% of commercially reared bumble bee colonies worldwide are used in tomato greenhouses — but these are mostly the European buff-tailed bumble bee (Bombus terrestris), a different species that shares the same mechanism as the rusty patched bumble bee.

If extinction occurs

If the rusty patched bumble bee's decline continues to extinction, wild plants and local crops of the Upper Midwest and Northeast would lose a buzz pollinator — but unlike the European buff-tailed bumble bee, reared commercially at scale, no study has precisely quantified what this particular species contributes relative to the other wild bumble bees that partly share its role.

Extrapolated
Detail

Extrapolation à partir du mécanisme de pollinisation par buzz documenté au point précédent, propre au genre Bombus, appliqué à cette espèce précise.

Most economic studies of buzz pollination focus on bumble bees reared in captivity and deployed in greenhouses, not on the residual wild populations of a specific critically endangered species like the rusty patched bumble bee.

What's missing to confirm it: A study isolating the rusty patched bumble bee's specific contribution — rather than that of the genus Bombus as a whole — to the pollination of wild plants and crops across its residual range is still missing.

Documentation

Last verified: August 7, 2026