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FIGURE 1. Bumblebees are dependable pollinators for a variety of shrubs commonly found in the home landscape, such as Duranta (pictured above).

   
 

 

FIGURE 2. Bumblebees are well-suited for pollinating plants that have long, narrow corollas such as trumpet vine (shown above in a not-so-focused photo).

   
 

 

FIGURE 3. For many years, commercial growers employed humans with electric vibrators to accomplish pollination of greenhouse-grown tomatoes. Today these have been mostly replaced with cultured bumblebees who do it more efficiently and cheaply.

   
 

 

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There are approximately 50 known species of bumblebees in North America. They are large bees with plump bodies typically sporting a range of colors based on the species from black and yellow bands to ones with orange, red or buff-colored bands. All are covered with fine hairs or “pile” that tends to give them a somewhat fuzzy-looking appearance.

Bumblebees are “social” insects; the colony is a “three-caste” society (queen, workers and drones). With the exception of the fertilized queen, the colony expires with the approach of winter. The bumblebee queen overwinters alone and in the spring builds a new nest for egg laying and the creation of a new colony.

A bumblebee colony ranges in size from 30 – 400 bees and is typically located in the ground; however, queens will also establish nests in objects above the ground, such as abandoned birdhouses and mouse nests, old flower pots, tires, insulation, grass clippings, and other debris.

Bumblebees store relatively minute amounts of honey, so their honey production is of no commercial value. Though normally very docile while foraging, bumblebees can be defensive of their nests and a single bumblebee is capable of stinging multiple times.

Bumblebees typically forage less than 2 miles from their nest. Though not of the commercial importance of honey bees, bumblebees are valuable pollinators—responsible for about 15% of the pollination of U. S. grown crops. Bumblebees have several factors in their favor as crop pollinators:

► They are native to the northern temperate regions, thus they are able to “fly” in lower temperatures than honey bees

► Bumblebees will forage plants that do not produce nectar

► Their bodies are covered with fine hairs that easily attract and hold pollen particles

► They have long tongues.

These attributes make the bumblebee well suited for pollinating plants cool season crops that have long, narrow corollas, such as clover, alfalfa and vetch; all important forage crops for livestock.

While bumblebees are capable of pollinating any crop, they are readily used for cotton, blueberries, cranberries, cabbage, watermelon, peppers, carrots, squash, cucumbers, eggplants, strawberries, raspberries, apples, and plums.

The bumblebees small nest size is particularly attractive to greenhouse gardeners for crops such as tomatoes. Commercial rearing of bumblebees to replace hand-pollinated greenhouse crops began over a decade ago in northern Europe (mainly focused Bombus terrestris) and later spread to Israel and Canada.

Bumblebees are susceptible to several parasites - Locustacarus buchneri (tracheal mites), Crithidia bombi (a protozoan), and Nosema bombi (microsporidia). And like the honey bees, bumblebees are vanishing! Many native bumblebee species are becoming extinct due to habitat destruction and improper use of pesticides (such as drift, timing, application to non-target areas, etc.) in the U. S., as well as other countries.

Beneficials in the Garden & Landscape is an Earth-KindTM program coordinated through Extension Horticulture at Texas A&M University. Earth-Kind uses research-proven techniques to provide maximum gardening and landscape enjoyment while preserving and protecting our environment.

 

This web site is maintained by Master Gardener Laura Bellmore, under the direction of William M. Johnson, Ph.D., County Extension Agent-Horticulture & Master Gardener Program Coordinator.

All digital photographs are the property of  the Galveston County Master Gardener Association, Inc. (GCMGA) © 2002-2006 GCMGA - All Rights Reserved.