Bombus spp.

Photo by Jimmy Lee
Species Description and Taxonomy
Bumblebees, which comprise many species within the genus Bombus (family Apidae), are one of the most important insects in the world. It is estimated that bumblebees pollinate up to 30% of North America’s food supply, an ecosystem service estimated to be worth over $20 billion. Bumblebees are social insects that usually have bands of soft, fuzzy, black and yellow body hairs covering their entire body. Like honey bees, bumblebees feed on nectar from flowers and gather pollen to feed their young.
Distribution and Habitat
Bombus species are native to every continent except Australia and Antarctica, and have been introduced to parts of New Zealand. Bumblebees live in various climates and typically have a life cycle running from spring to fall; only the queens hibernate underground during winter. In warm tropical climates, bumblebees are able to live year round. Bumblebees typically nest underground in pre-existing holes or crevasses, which they modify with nectar. Bumblebees serve as pollinators because pollen sticks to their feet electrostatically when feeding and is transported to other flowers, fertilizing them in the process.

Bumblebees have two complex eyes and three simple eyes between them. They have an open circulation system and their heart is a simple tube. The wings of the bumblebee attach at the thorax, the base of the nervous system. Bumblebees are able to warm up their body using their flight muscles, an action analogous to shivering in humans. Bumblebees also are covered in thick pile that insulates them.

Ecological Relationships
Bumblebees are prey for many vertebrates such as mice, moles, shrews, skunks, weasels, foxes, and bears. Several insects also exploit bumblebees, such as Psithyrus, or “cuckoo bees” that live parasitically in bumblebee colonies.

Status and Conservation
Bumblebee populations in most areas are declining due to habitat loss and fragmentation, as well as from pesticide use in agriculture.

Many thanks to Tyler Smith and Dr. Pat Magee at Western State College for this submission, and to RMBL Researcher Dr. David Inouye of the University of Maryland for his review and additions.

Encyclopedia of Life
Learn more about Bombus ssp. at the Encyclopedia of Life.

Kearns, C., and J. Thomson. 2001. The natural history of bumblebees: a sourcebook for investigations. University Press of Colorado, Boulder, Colorado, USA.