By Jody Green, Extension Educator
The sign of a bee or wasp flying around in the air can be a source of fear and anxiety for many people. In nature, both bees and wasps play beneficial roles: bees pollinate many landscapes and agricultural crops, and wasps are predators and biocontrol agents of many insect and arthropod pests. Both adult bees and wasps feed on sugary substances such as nectar, plant sap and rotting fruits.
Knowing how to identify the insect and determine whether there is a high-sting risk, will help families protect themselves and enjoy summer to the fullest. Bees and wasps are classified as either social or solitary insects.
SOCIAL BEES AND WASPS
Social bees (honey bees and bumble bees) and wasps (paper wasps, yellowjackets, hornets) live in large colonies and can become aggressive when threatened.
Honey bees are perennial species that survive the winter. Sometimes, honey bees swarm when the queen and a large number of worker bees leave the hive in search of a new location like a hollow tree, wall void or other protected area.
All other social colonies are annual, which means they are founded each spring by a lone, fertilized queen that has overwintered in a protective site. As the weather warms up, she becomes active and begins to search for a suitable location to begin construction of her nest.
Bumble bees typically nest in protected sites underground like abandoned rodent burrows or under sheds, but can also nest above ground in compost piles, bird boxes and thick grass.
Paper wasps, yellowjackets and hornets live in paper nests, constructed by the founding queen using chewed up wood fibers and saliva.
Paper wasp nests consist of a single-layer of downward-facing, exposed cells which are normally constructed under a horizontal surface like the overhangs of buildings or inside cavities.
Yellowjacket and hornet nests consist of a series of round combs, stacked in tiers and covered in a paper envelope. They can take the form of a ball-shaped, aerial nest or in an underground burrow or inside a wall void or attic.
SOLITARY BEES AND WASPS
Solitary bees and wasps which live and forage alone are usually quite docile. Sometimes they nest in aggregations in lawns and landscapes, but each female builds her own nest to provision with food for her larvae.
Solitary bees include carpenter bees, digger bees, sweat bees, mining bees, mason bees and leafcutter bees. The lone, fertilized female prepares each cell with pollen, nectar and her own egg. The species determine the location and material with which she builds her nest and chambers.
Solitary wasps include cicada killers, mud daubers, digger wasps, grasp-carrier wasps and sand wasps. Solitary wasps are parasitoids where they capture live organisms for their offspring and lay an egg on the body for their emerging larvae to feed on. The female provisions her cells and chambers with paralyzed prey, which, depending on the species, may contain cicadas, spiders, crickets, flies or caterpillars.
AVOID ATTRACTING WASPS
The best method to avoid wasp stings is to prevent them from nesting in highly frequented areas. Sealing holes and closing gaps in walls, capping pipes and equipment, and inspecting preferred areas will help deter nest building.
Many wasps are scavengers and will forage on a wide variety of foods, especially sweets in trash cans, open containers, spilled pop and rotting fruit. The best way to prevent wasps and yellow jackets in recreational areas is to minimize the time uncovered food and drink remain outdoors. If sweet beverages are left unattended, inspect to make sure a foraging wasp won’t end up in your mouth.
PEST STATUS OF WASPS
Bees and wasps become pests when they construct nests and forage in urban areas, such as houses, schools, businesses and other locations where humans frequent. Only female bees and wasps are capable of stinging because the stinger is a modified ovipositor or egg-laying device.
In general, solitary bees and wasps do not defend their nests and are not aggressive. (Male carpenter bees and male cicada killer wasps may demonstrate territorial behavior, but they lack the ability to sting.)
Social bees and wasps can become a hazard for humans when their nests are disturbed or the colony feels threatened. This can occur when there is a ground nest of bumble bees or yellowjackets and someone mows overhead. Bumble bees and social wasps can sting repeatedly.
TREATMENT FOR BEE OR WASP STINGS
Stings inflicted by bees and wasps are characterized by moderate to severe pain, localized reddening and swelling, but most people can recover after a few days. In the case of a minor reaction to a bee or wasp sting, wash and clean the area with soap and water, and then apply a cold compress of ice to relieve the pain and ease any swelling. Honey bees have barbed stingers, which will remain in the skin and continue to release venom until it is removed, so it is important to remove the stinger by scraping it out with a straight-edged object. Some individuals suffer life-threating anaphylaxis in response to the venom of bees and/or wasps and require immediate medical attention (i.e. EpiPen).
FINDING AND TREATING THE NEST
We do not recommend any treatment for solitary bees and wasps unless they are a heath concern or causing structural damage. If honey bees swarm or established a hive in a wall void, it is best to call a local beekeeper to come and remove them. Bumble bee nests should not be treated unless absolutely necessary, as they are valuable pollinators, but where they pose a threat to humans, it may be warranted.
Though the best time to find the nest is during the day when foraging behavior can be observed, the best time to treat the nest is after dark. This is the most opportune time because temperatures are cooler and all foragers are in the nest. Attempting to treat during the day is not advisable because high numbers of active wasps increase the potential for defensive stings.
CHEMICAL CONTROL FOR SOCIAL WASPS
There are many products labeled for wasps with different active ingredients (toxicants) available at local hardware stores. It is best to treat the nest in early summer when colonies are below peak population numbers and aggressive behavior is not yet evident. Always read and follow the insecticide label. Do not spray indoors!
Some situations may call for a professional pest management company, especially if people/children are at risk and the nest is extremely difficult to treat. Professionals have specialized equipment and training to complete the job safely during the day.