Bee Pollination

Bees are the champion pollinators!

In the United States, there are over 4,000 species of native bees. Familiar bees visiting garden flowers are the colorful, fuzzy, yellow-and-black striped bumblebees, metallic-green sweat bees, squash bees, and imported honeybee. These flower-seeking pollen magnets purposefully visit flowers to collect pollen and nectar for food for themselves and their young.

Energy Needs

All bees have very high-energy needs that must be met for their survival. Bees need key resources such as pollen and nectar from a variety of flowers. Bees need these resources for themselves and their progeny. Many bees need water in addition to nectar.

Nesting Habitat

Bee nesting habits vary greatly. For example:

• Mason bees construct nests from mud.
• Leafcutter bees use a "wrapper" of leaves, resin and sand.
• Carder bees harvest plant fibers.

Most bees excavate their nest tunnels in sunny patches of bare ground, while others seek out abandoned beetle burrows in dead tree trunks or branches. The majority of bees are solitary, but a few, like sweat bees, bumblebees, and honeybees, are social, living in colonies that consist of a queen, her worker bee daughters and a few males, the drones.

Bee Flowers

The flowers that are visited by bees are typically:

• Full of nectar
• Brightly colored with petals that are usually blue or yellow or a mixture of these (bees cannot see red)
• Sweetly aromatic or have a minty fragrance
• Open in daytime
• Provide landing platforms
• Often bilaterally symmetrical (one side of the flower is a mirror image of the other)
• Flowers are often tubular with nectar at base of tube

An example of a bee-pollinated flower is a snapdragon or Penstemon (pictured right). Snapdragon flowers have sturdy, irregular shaped flowers with landing platform. Only bees of the right size and weight can trigger the flower to open. Other bee species or other insects that are too small or too large are excluded.

Nectar Guides

Many of the flowers pollinated by bees have a region of low ultraviolet reflectance near the center of each petal. This region appears invisible to humans because our visual spectrum does not extend into the ultraviolet. However, bees can detect ultraviolet light. The contrasting ultraviolet pattern called a nectar guide. This guide helps a bee quickly locate the flower's center.

This adaptation benefits both the flower and the bee. The bee can more rapidly collect nectar and the flower is more effectively pollinated.

For More Information

For more information about bees, building bee habitat, or bee gardens visit the following links:

• Insect Basics
• What's the Buzz on Planting a Bee Garden?
• Building Native Bee Nesting Blocks: Home-Made Sweet Homes
• Build a Nesting Block
• Urban Bee Gardens, A Practical Guide to Introducing the World's Most Prolific Pollinator into Your Garden
• Bee Basics, An Introduction to Our Native Bees (PDF, 1.5 MB), by Beatriz Moisset, Ph.D. and Stephen Buchmann, Ph.D. A USDA Forest Service and Pollinator Partnership Publication.
• Bumble Bees of the Eastern United States (PDF, 5.9 MB), by Sheila Colla, Leif Richardson, and Paul Williams. A product of the USDA Forest Service and the Pollinator Partnership with funding from the Naitonal Fish and Wildlife Foundation.
• Bumble Bees of the Western United States (PDF, 7.7 MB), by Jonathan Koch, James Strange, and Paul Williams. A product of the USDA Forest Service and the Pollinator Partnership with funding from the Naitonal Fish and Wildlife Foundation.

Conservation and Management of North American Bumble Bees

This is a report of the USDA Forest Service and NatureServe with funding from the National Fish and Wildlife Foundation. This document provides a brief overview of the diversity, natural history, conservation status, and management of North American bumble bees, genus Bombus. The spring to late summer period of colony founding, build up, and production of reproductive individuals, followed by the overwintering of new queens provide the natural history basis for management considerations of the approximately 46 North American species. Most bumble bee species are currently not threatened or documented as declining except in areas of intensive agriculture. Eight species from three subgenera, however, have declined drastically during the last 15-20 years. These include three species that are obligate parasites on other declining species. The pathogen spillover hypothesis, which proposes that diseases from infected commercial colonies imported from Europe are infecting native populations of closely related species, may explain the sharp declines of most species. Other threats to bumble bees include climate change, loss of nesting and foraging habitats and pesticide use.

Schweitzer, D.F., N.A. Capuano, B.E. Young, and S.R. Colla. 2012. Conservation and management of North American bumble bees. NatureServe, Arlington, Virginia, and USDA Forest Service, Washington, D.C.

Read the report (PDF, 2.8 MB)…

Bumblebees of the Eastern United States

Twenty-one species of bumble bees (Bombus spp.) occur east of the 100th meridian. This poster made available by the Pollinator Partnership, depicts the bumble bee species occurring east of the Mississippi River in the United States.

Art and Design: Steve Buchanan

Download Print Size Version (PDF, 68.5 MB)

Download Reduced Size Version (PDF, 1.4 MB)

Bumblebees of the Western United States

Bumble bees (Bombus spp.) are vitally important pollinators of wild and managed flowering plants. In the contiguous United States 30 species of bumble bee are found west of the Rocky Mountains. This poster made available by the Pollinator Partnership, depicts the bumble bee species occurring west of the Mississippi River in the United States.

Art and Design: Steve Buchanan

Download Print Size Version (PDF, 16.1 MB)

Download Reduced Size Version (PDF, 4.4 MB)