Social Bees and Wasps

It is instantaneously painful and can linger for days. Most of us get a mild reaction from it, but a few of us need immediate medical attention or our life is at risk. One thing is certain, from a bee or wasp perspective, the stinger is a marvelous defense mechanism and always accomplishes its purpose. Once stung, you will vividly remember for the rest of your life that bees and wasps are well equipped to defend themselves. Anatomically speaking, the stinger is a modified egg-laying apparatus. Therefore, male bees and wasps are not capable of stinging. Although many people refer to stings as “bites”, most bees and wasps cannot actually bite—their mandibles are not strong enough to pierce skin.

Without bees and wasps, life as we know it would be significantly different. Bees are very efficient pollinators and a third of our diet—most seeds, nuts, fruits and vegetables—require their pollination services. Wasps, on the other hand, help protect our gardens, by eating countless numbers of pests. Wasps can also have a role in pollination, since they frequently visit flowers for their nectar. However, despite their crucial role in both agricultural and natural environments, most of us see bees and wasps as a nuisance. While it is natural to avoid as much as possible being stung, some of us have unfortunately developed a bee-and-wasp phobia. But is it really justified?

In the U.S., there are about 50 human fatalities attributed to bees and wasps every year, and people who are allergic to bee and wasp venom should take all necessary precautions. But, for most people, knowing that there are only a few species of bees and wasps that are defensive and under what circumstances, can significantly minimize the threat of painful encounters.

Based on their lifestyle, bees and wasps can be separated into two categories: social and solitary. Social bees and wasps live in colonies. Many of us are familiar with the social structure of a honeybee colony. The queen lays the eggs, while workers build the nest, tend to the young, and bring in food provisions. Males, in both social and solitary bees and wasps, do no “household” chores and have only a reproductive role. In solitary bees and wasps, there is no queen-and-worker social structure. Each female singlehandedly builds the nest, collects food, and lays eggs. Because they live by themselves, solitary bee and wasp females avoid conflict with humans, even when their nests are disturbed. This, however, is not the case with social bees and wasps, which can be highly defensive.

In the U.S., less than 5% of all bee and wasp species have social lifestyles. The social bees and wasps in the U.S. are honeybees, bumblebees, yellow jackets, white-faced (or bald-faced) hornets, European hornets, and paper wasps. Visit www.facebook.com/4wasps for pictures and more information on these bees and wasps. Of all these, in Pennsylvania only honey bee colonies can live for several years. All other social bee and wasp colonies die in the winter and only the new, mated queens overwinter. The following year, starting in April, these queens singlehandedly establish new colonies. Once there is a sufficient workforce in the colony, they will no longer venture outside of their nests, and they will only specialize in laying eggs. Males and new queens are produced sometime in early August. These new queens mate and overwinter away from the colony. All old queens, workers, and males die off with the first frost.

Among all social bees and wasps, yellow jackets are by far the most defensive. Like all other social wasps, yellow jackets build paper nests out of chewed wood fiber. They usually build their nests in underground cavities formed by rodents or decayed roots, but can also take residence in walls, mulch piles or bird houses. Yellow jackets cannot dig their own cavities, but they can enlarge existent ones to accommodate their growing nests. A large colony of yellow jackets can have hundreds of adults and just as many eggs, larvae, and pupae. We usually start noticing their nests in late summer, at the peak of the colony when numerous yellow jackets fly in and out of the nest. At this time, yellow jackets reduce their consumption of other insects and become scavengers, searching for sugar-rich foods and drinks. Covering foods, drinks, and leftovers is the best way to ensure that yellow jackets do not visit our picnics.

The next highly defensive social wasp is the white-faced hornet. These wasps are not technically hornets, but actually close relatives of yellow jackets. Unlike yellow jackets, which are black with yellow stripes, white-faced hornets are black with white stripes. These social wasps build aerial paper nests that look like large, grey footballs. The size of the nest can vary greatly, depending on the colony’s rate of success. Most nests are located in trees and attached to branches, but can sometimes be located on walls or other protected areas. White-faced hornets do not scavenge like yellow jackets do. Just like all other social bees and wasps, white-faced hornets do not reuse the old nest next year. At the end of the colony’s life, many animals will scavenge on the colony’s leftovers.

European hornets are the only true hornets in the U.S., and just as the name implies they were introduced from Europe, sometime in the 1840s. These wasps are the largest social wasps in Pennsylvania. Despite their size and painful stinger, European hornets are far less defensive than yellow jackets and white-faced hornets. Furthermore, they are not as common as the rest of the social wasps. European hornets often establish their nests in forested areas. They usually take residence in hollow trees, but sometimes they are found in attics, sheds or barns. Their nests have a brownish color and are significantly larger than all other social wasps. Like all other social wasps, European hornets prey upon a variety of insects, including flies, grasshoppers, cicadas, wasps, and various caterpillars.

There are many species of paper wasps in Pennsylvania. Compared with other social wasps, paper wasps have small colonies with only a few dozen adults. Partly because of this, paper wasps are less defensive. Their nests look like upside down mushrooms and have no protective paper envelopes around them, unlike all other social wasp nests. Most paper wasps are dark red with various markings. The European paper wasp, a recently introduced species, is black with yellow markings, closely resembling a yellow jacket. A paper wasp, however, has an elongated waist, while a yellow jacket’s waist is less noticeable.

Both honeybees and bumblebees build their combs out of wax. Feral honeybees tend to be a rarity nowadays, since most colonies have been wiped out by imported pests and diseases. Homeowners can occasionally come across a swarm—or a large cluster—of honeybees. Swarming represents the division of one colony into two; where an old queen takes half of the working bees and searches for a new nesting site. Swarms are generally not aggressive and tend to relocate once a nesting site has been found. Because they are perennial and can have tens of thousands of workers, honeybee colonies that reside in walls or roofs can pose long term liabilities. It is best to ask for professional help when it is necessary to remove a honeybee colony. 

In Pennsylvania, there are more than a dozen different species of bumblebees. Different species can be distinguished from each other based on the color of their abdomen segments. The most common bumblebee species resembles the carpenter bee. However, carpenter bees have a shiny abdomen, while bumble bees have a fuzzy one. Bumblebee colonies have only several hundred workers. While they don’t technically make honey, they do store small quantities of nectar. Bumblebees are very opportunistic, and tend to build their nests in rodent cavities.

When dealing with a colony of bees or wasps, keep in mind that with the exception of honeybees, all social bees and wasps die out with the first frost. Should you decide to let nature take its course, minimize traffic, mowing, or other vibration-making activities in the area close to the nest. Inclement weather makes social bees and wasps more irascible. Also, the larger the colony the more likely it is to be aggressive. Therefore, when necessary, it is best to remove a social bee or wasp nest early in the season, before the worker population is numerous. The safest way to remove a colony is to hire professional help. If you intend to do it on your own it is best to act at night. Most outdoor equipment stores sell various wasp sprays. At nighttime, use a flashlight covered with red cellophane since bees and wasps can’t see red light. Wear protective clothing and equipment, such as a bee veil and gloves. If the colony was located in the ground fill the hole with soil after the nest is eliminated.

If you need more information on bees, wasps or other critters, contact Penn State Extension in Franklin County at 717-263-9226.

Alex Surcica is a Penn State Extension Educator in Horticulture and Pollination.