Summer is here and with it — wasp season. Yellow and black, all black, darting or hovering, we all react and often recoil when wasps are near us. Wasps are common around our dwellings, outbuildings, gardens and fields. Some are entirely beneficial and benign, others both beneficial and bothersome.
Around our households, many are universally targeted by insecticidal sprays without determining what type they are. Our commonly occurring wasps are worth getting to know, and many surprises await those who take the time to do this.
Common wasps in urban, suburban and rural areas are the ground-nesting yellowjacket wasp (Vespula pensylvanica), the nonnative European paper wasp (Polistes dominula), the mud dauber wasp (Sceliphron caementarium) and the blue mud dauber wasp (Chalybion californicum).
Wasp life cycles are interesting. Wasps can be social, like honeybees with a queen and many workers, except with annual, not perennial, colonies. They can also be solitary. Solitary wasp females work alone to construct a nest and provision it with insects for the young or larvae. They are not considered defensive. Social wasps such as yellowjackets are extremely defensive of nests and can constitute a real hazard to us.
Fertilized female wasps (queens) emerge in spring from overwintering sites in the ground, under leaves, bark, in attics, or outbuildings. They seek a nest location and begin laying eggs and provisioning it for the young. Each wasp type constructs a different type of nest and targets different insects or food as prey.
Many wasps are both carnivorous and nectar feeding. Most adult wasps, except yellowjackets, feed on insects for protein and flower nectar for energy. Yellowjacket young and queens are fed insects and meat all season. Workers feed on meat (including our food), insects and sugary substances.
Mud dauber wasps are some of the most interesting and beneficial to us. They are very long and slender with distinctive, threadlike waists and long legs that dangle when flying. They construct small mud nests on the interior walls or eaves of garages and outbuildings. With the arrival of warm weather, spring cleaning is usually on the agenda. The small mud wasp nests adhering to walls and ceilings are often sprayed with insecticide and cleaned away.
Mud dauber wasps are solitary, and females are not defensive of nests. They are specialized spider hunters and capture them to provision nests. After nests are complete, they don’t attend the young as social wasps do.
The larvae get nourishment from spiders that females have captured, paralyzed and used to pack the nests. Each mud nest may be composed of 15 to 20 cells. Each cell is packed with around 20 to 30 paralyzed spiders. This may add up to 500 spiders captured by each female wasp, and if broken open is an interesting science project.
If this is interesting, it only gets better. You may see a large, iridescent blue/black, very slender wasp visiting mud dauber nests. This is a female black mud dauber wasp, another solitary species.
The black mud dauber wasps reuse and sometimes steal mud dauber wasp nests. The primary prey they provision nests with is black widow spiders. A good reason to leave mud dauber nests intact!
Female mud dauber wasps of both types use special tactics to capture spiders. They are able to land on webs without being ensnared and pluck the strands to mimic prey. The spiders then become a victim of the wasps’ paralyzing sting when they come out to look for victims.
The wasp females feed on flower nectar for energy and spider fluid for protein. Accessible mud helps the wasps build nests. For spider control, some people put saucers of mud outside their house, garage and barns to encourage mud dauber wasps to build nests.
Please note that just a very few spiders have painful or poisonous bites. Many are important, generalist predators in our gardens.
Many wasps (and bees) are mistaken for the aggressive, ground-nesting, social yellowjacket wasps or the social, nonnative European paper wasps. Both live in colonies with a queen and many workers. The paper wasps construct hanging paper nests under eaves and on bushes, trees and arbors.
European paper wasps were first seen in the United States in 1970 in the Boston area and have since spread across the northern states and western Canada.
They are also very long, slender, and yellow and black with distinctive threadlike waists and long legs that dangle when flying. These wasps are primarily caterpillar hunters and capture them to feed to young. These wasps, while annoying when nests are inconveniently placed, can be beneficial to our farms or gardens in capturing pest caterpillars, but also use butterfly caterpillars as prey.
The adults mostly feed on nectar. As they are social, they defend the nests that can number up to about 200 wasps. Nests are seasonal, and the colony dies at the end of the season, with new queens surviving to overwinter and begin the cycle anew in the spring.
In some areas, they proliferate and can become a real problem. An easy way to control the European paper wasp is to put an extension on a Shop-Vac and simply vacuum nests up in the cool of the morning or early evening.
The yellowjacket wasp nests mainly in the ground. Chance encounters with them are dreaded. They nest around our houses, fields and wild lands.
Fertilized females (queens) emerge in spring, as temperatures warm, and scout for a place to nest. They are substantial in size and are a dull yellow and black. Early spring into early summer is the perfect time to set out traps. Each queen captured is one less that will make a nest.
Over the course of a season, nests can number in the hundreds of workers and are a substantial hazard if disturbed as workers mobilize and attack. As food supplies dwindle in the late summer and fall, yellowjackets become particularly bothersome and target sugary drinks such as soda or grape juice at wineries.
Yellowjacket queens and larvae are fed insects, carrion and meat. Workers feed on sugary substances in the colony and meat and insects.
At the end of the season, workers are no longer fed in the colony and become hungry and even more aggressive. They raid honeybee hives and can be a real problem for beekeepers. New queens are produced at the end of the season, seek a place to overwinter and the rest of the colony dies.
It is worthwhile to get to know your wasps!