Bumble Bee Nest, Vol. 9, No. 07
Bombus spp.
Order: Apidae
Family: Hymenoptera
“We kept seeing bees flying in and out of our blue bird box, so we sprayed it and cleaned it out. This is what we found inside. Is this really a bumble bee nest?”
Yes, this is a small bumble bee nest; you can even see a developing larva in that cell that has been torn open. Bumble bees overwinter as mated females. They mate in the fall, forage heavily on pollen and nectar to build their energy reserves, then find a protected place to spend the winter. When they emerge in the spring, they need to find a suitable place to start their nest. This is usually in some pre-existing cavity in or near the soil, often in the abandoned nest or burrow of some small mammal or bird.
Most nests are in or very near the soil, such as under a stump, rock, debris pile or fallen log, but occasionally bumble bees will nest above the ground, and nests are occasionally encountered between stacked bales of hay, in wall voids, empty bird houses, and similar sites. Most people who spend time outdoors have had unfortunate encounters with bumble bee nests in such places! Nests start out small in the spring, just the queen and a few workers, but by late summer a large nest can contain hundreds of workers, all of which will aggressively defend the nest if it is disturbed.
Like honeybees, bumble bees are important pollinators that rear their young and store nectar and pollen in wax cells within the nest. But the wax cells or “honey pots” of bumble bees are not six-sided and uniform in size like those of honeybees. Some of these cells are used for rearing brood and others are used for storing pollen and nectar. Bumble bees collect and store nectar, but they do not convert it into honey. Bumble bee nests do not survive through the winter, so they do not need long-term food storage like honeybee colonies.
You may have noticed that the bumble bees you see foraging on flowers in your yard and garden vary greatly in size through the year. This could be because you are seeing different species. Eastern bumble bee, B. impatiens, is our most common species, but there are many other species of bumble bees in the Southeast. But it is mostly because “big momma bumble bees,” the overwintered queens we see foraging in the spring and the next year’s queens we see in the fall, are much larger than the workers.
See Bug's Eye View No. 30 of 2015 for a brief article on the use of commercially purchased bumble bee hives to pollinate greenhouse tomatoes and other crops.
Bumble bees are not always beneficial. Nests that are in the wrong place can pose serious sting risks. See pages 12-14 of Publication 2331, Control Insect Pests in and around the Home Lawn for information on how to deal with such nests. When dealing with stinging insects there is always the risk of being stung. Wear protective clothing and take all necessary precautions! Don’t hesitate to call a professional pest control company if the situation is beyond your abilities or comfort level.
Blake Layton, Extension Entomology Specialist, Mississippi State University Extension Service.
The information given here is for educational purposes only. Always read and follow current label directions. Specific commercial products are mentioned as examples only and reference to specific products or trade names is made with the understanding that no discrimination is intended to other products that may also be suitable and appropriately labeled.
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