Dealing with social bees and wasps

I have had numerous calls about bees or wasps inside building structures lately. Normally, it’s an attic, a wall, a crawl space or possibly an accessory structure, and the call goes something like, “I’ve been killing a bunch of bees every day, and they’re still there.”

Insects that form an elaborate nest and function as a colony are called “social” bees or wasps. This behavior is opposed to solitary bees that form a single nest for rearing young, do their own thing, and rarely sting.

Bees and wasps, as a general rule, are all beneficial insects. The beneficial work these insects perform include pollination of vegetable, fruit and nut crops, and the predation of other insect pests.

However, when bees or wasps invade homes, cause damage by their nesting activity, or interfere with other human activities, “beneficial” is not the first word that comes to mind. It’s also hard for us to think of bees as beneficial insects when we have lasting memories of getting stung as a child, let alone those who have allergic reactions to bee and wasp venom.

Examples of social bees and wasps that can give homeowners problems include honey bees, bumble bees, yellowjackets, paper wasps and hornets. These insects are covered in Purdue Extension publication E-44-W, authored by Purdue Extension entomologist, Tim Gibb, entitled, “Social Bees and Wasps.”

Honey bees have been known to establish their colony inside a wall void, chimney or attic. I have received calls from people over the years that report honey dripping down the inside of their wall. Of course, the only effective way to deal with this problem is to deconstruct the wall, remove the colony, clean the wall void, and reconstruct the wall. Local beekeepers love to retrieve wild honey bee swarms, but are less enthusiastic about getting a hive from a home.

Bumble bees, another good pollinator, typically form smaller underground colonies, but these colonies may be in a homeowner’s yard near his home. They defend their nest and can be a significant stinging threat.

One of the more common social wasps to present problems around a home is the yellowjacket. These are the shiny yellow and black wasps you typically see around garbage cans in a city park. These wasps can form underground nests or nests in buildings. They defend their nest and can present a significant stinging threat. Colonies can become quite large by late summer and fall, and are often located far from the entrance hole, deep into the structure.

Paper wasps build single, exposed nest combs typically suspended from eaves or outbuildings. They can potentially sting.

European paper wasps have become more common in Indiana and can form elaborate nests in voids of lighting fixtures, gas grills, and other infrequently used spaces.

The baldfaced hornet is most readily identified by the shape and location of their nest. These insects build the familiar large grayish, pear-shaped or football-shaped nests that often are suspended in trees or on sides of buildings. If you’ve heard the phrase, “mad as a hornet,” it should give you a clue as to why you shouldn’t mess with these nests.

European hornets can build colonies in areas similar to that of structural nesting yellowjackets.

Pest control companies may need to be employed for safe control of some of these bees and wasps. Otherwise, if some areas can be avoided until winter, most nests will be abandoned and not reused next year. In those cases, if you can wait until the dead of winter to clean out the nest, it would be the safest time. The exceptions are honey bees (perennial nests) and European paper wasps (can reuse old nests). Make efforts to conserve bees and wasps if possible.

For more information about social bees and wasps, including control strategies, search for Gibb’s publication at The Education Store for Purdue Extension at mdc.itap.purdue.edu.

John Woodmansee is an extension educator in Whitley and Noble counties.

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