Fascinating facts about wasps, hornets

Published 9:36 am Thursday, July 1, 2021

How to get along with these beneficial bugs

Written by Adam Russell
adam.russell@ag.tamu.edu

Murder hornets may make the headlines because of their frightening name, but they are not in Texas. So, let’s talk about wasps and hornets and precautions you can take to avoid stings.

All wasps and hornets are beneficial, said Wizzie Brown, Texas A&M AgriLife Extension Service entomologist, Austin. Homeowners can appreciate that they protect gardens and landscapes from pests like caterpillars, spiders and aphids and pollinate blooming plants, but a sudden sting can erase that goodwill quickly.

Brown said wasps and hornets are focused on building nests and rearing young in any naturally occurring location or man-made structure that provides protection from the elements like eaves of buildings, bushes and trees.

Wasps and hornets are typically not aggressive when they are out foraging around flowers or a trash can, Brown said, so it is best to remain calm and avoid making aggressive movements toward them. However, certain species are very protective of their nests.

“If nests are in an area that won’t be disturbed, they typically are not going to be an issue,” she said. “They become a problem when they are protecting their nests and babies, so a nest by the front door or on your kids’ playset would be a concern.”

Brown said other locations like doghouses and mailboxes are a few locations homeowners should monitor for nests. If hornets or wasps are flying around a specific spot regularly, there is a possibility a nest could be present or in the making.

All sorts of shapes, sizes, nests and aggression levels

Yellow jackets are small with black and yellow banded markings. They are often misidentified because other species, like certain paper wasps, have similar reddish-brown bodies with yellow stripes. A large ground-dwelling species known as cicada killer wasps also have yellow and black banded markings but can reach up to 2 inches in length.

The cicada killer wasps’ size has caused it to be misidentified as the murder hornet, or giant Asian hornet, which has not been officially sighted outside of Washington state so far.

Wasp and hornet species display a range of aggression when it comes to encroachment, Brown said. Yellow jackets are very protective of their colony and may attack when their nest is threatened, including vibrations from mowing. Mud daubers, on the other hand, are very docile and typically only sting when handled roughly.

Only female wasps and hornets sting, Brown said. The stinger is a modified egg-laying structure called the ovipositor. But males of some species like the cicada killer wasp will display more territorial aggression to an intruder than females, despite its inability to sting.

Brown said paper wasps are probably the most common wasps people encounter across Texas. They build open-faced paper nests typically in aerial locations and can be aggressive when their home is disturbed. Nests are a single layer and hang from a single stalk.

“If you see an open-faced nest made out of papery material on the eave of your home or along the ceiling of your porch, there’s a good chance they are paper wasps,” she said.

The type of nest structure and its location can be helpful hints as to what species is present.

Yellow jackets, for instance, build paper nests made of chewed wood fiber like paper wasps but build single-entry colonies and are most commonly found in cavities or underground spaces like abandoned rodent burrows.

Mud daubers, on the other hand, collect moist soil and build a structure that they provision with food and lay their eggs. They can build these nests relatively anywhere protected from the rain. Once they’ve filled the structure with eggs and food like spiders, they seal the nest and leave.

Cicada killer wasps burrow into the ground to nest. They are typically solitary nesters but will share a single entry in the ground that leads to several egg-laying nurseries.

Wasps and hornets are fascinating animals,” Brown said. “It’s easy to take the good they do around our homes for granted because we are afraid of being stung. But by learning what they do and how the different species act, it removes a lot of the fear and helps you appreciate seeing them around.”

Wasps and hornets come in a variety of shapes and sizes. AgriLife Extension and the Texas Apiary Inspection Service have great resources to help identify specific species by sight and behavior. Also, a recent Bugs by the Yard podcast featuring Brown and fellow AgriLife Extension entomologists covers wasps you might encounter around the state.

Controlling wasps around the house

Controlling where wasps and hornets locate around your home is relatively straightforward – kill the wasps and remove the nest. But the species and nest size present will dictate whether you can do it yourself or should call professionals.

“A mud dauber nest that is an eyesore on your home could be scraped off and washed,” she said. “The same goes for paper wasp nests, but you will need to spray the wasps from a safe distance beforehand. Spray them early in the morning or just before dark so you catch most of the wasps. Clean the space thoroughly after removing the nest to remove any pheromones that might attract other wasps to that location.”

Brown recommends using a spray pesticide that can shoot a concentrated stream 8-10 feet when removing stinging species like paper wasps.

Yellow jackets and hornets, especially those in established colonies, should be handled by professionals, Brown said.

“Earlier in the season, when the nests are smaller, removal might be something the DIY person could do, but when they are really active, removal could turn into a dangerous situation without protective clothing and specialized equipment.”

Brown said because yellowjackets and hornets can be very aggressive in protecting their nests and can sting multiple times, seeking shelter in a protected, closed area is the only way to avoid stings. Common swarm scenarios are a homeowner mowing their lawn and unwittingly alarming the colony through vibration or a farmer cutting hay and running over an underground colony.

“I would just recommend anyone who is consistently seeing any type of flying insect in a specific location that might be cause for concern – whether it’s around kids or your pet or a place you might disturb them – it might be worth taking a look to see what you’re dealing with. Be cautious and calm and don’t get too close, but knowing what insect you have could help you determine what the next step should be.”