In this article, we will try to cover all aspects of the grass carrying wasps, their habitat, what they eat, how they reproduce, and more.
Flying insects that build nests can often be a nuisance to homeowners.
If you find a bug nest in a window frame made of dried grass, it might be the handiwork of a grass carrying wasp.
While these wasps aren’t very dangerous, having them buzz around or build nests in inconvenient spots can be a bit annoying.
Let’s find out more about this interesting wasp species and how to deal with it.
What Are Grass Carrying Wasps?
Grass carrying wasps get their name from the fact that they are often spotted flying around with blades of grass.
More specifically speaking, it’s the females that display this unusual behavior, using tall grass to build their nests.
They are a species of thread-waisted wasps (Sphecid wasps), growing up to a length of 0.75 inches with a shiny black body.
You might want to note that grass carrying wasps are a solitary insect species, which means they build small nests and live by themselves rather than living in a colony.
What Does A Grass Carrying Wasp Eat?
Like most wasps, adult grass carrying wasps primarily feed on nectar and pollen.
Among native plants, they are especially attracted to mountain mint, rattlesnake master, boneset, and goldenrod.
The females also prey on insects, especially tree crickets and katydids. However, they do not feed on these insects themselves.
They paralyze the prey and drag them into the nest, to serve as food for the newborn grass carrying wasp larvae when the eggs hatch.
Where Do Grass Carrying Wasps Live?
Contrary to most Sphecid wasps, grass carrying wasps do not burrow underground. Instead, they mostly use aboveground cavities like hollow stems to build their nests.
They might, however, use pre-existing holes in the ground for this purpose. They’re often found to build nests in suitable indoor spots too, especially in door and window tracks.
It’s easy to mistake a grass carrying wasp nest for a random lump of dry grass that made its way to your home with the wind.
The grass nests may either have several brood cells partitioned by blades of grass, or a single communal area where all the larvae stay, feed, and develop.
The Lifecycle of a Grass Carrying Wasp
The life cycle of a grass carrying wasp isn’t very different from that of other common solitary wasps.
They go through the four life cycle stages typical of insects – egg, wasp larva, pupa, and adult.
Eggs
These wasps produce only one generation a year, or two at most. The eggs are laid in the grass nests they build. Adult female grass carrying wasps provision their nests with paralyzed insects for the offspring.
Larvae
The larvae hatch in a few days and spend the next week or so feeding on the cached prey. They molt during this time, developing and growing in size.
Pupae
Once the larvae have exhausted the food stored in the nest, they spin a cocoon around themselves.
They overwinter in their cocoons, either in a pupal or pre-pupal state, depending on their stage of development at the time of cocooning.
The wasp resumes development in the spring, eventually ending the pupal stage and emerging as an adult wasp.
Adults
Grass carrying wasps spend most of the adult stage of their life cycle foraging for pollen and nectar.
The females begin constructing their nests soon after mating, which is when you’d find them carrying blades of grass.
Once the nest is ready, the adult female wasp will start hunting in high canopies in search of prey, which she paralyzes and carries to her nests.
She lays her eggs once the nest is well-stocked with food.
Do They Bite/Sting?
Grass carrying wasps aren’t much of a threat due to their non-aggressive nature. Despite being stinging wasps, they’d sting you only if you made them feel provoked or threatened.
Unlike social wasps, they live alone and don’t have a colony to defend.
This significantly lowers the chances of getting stung because you got too close to a grass carrying wasp nest.
Grass carrying wasps are comparable to digger wasps in this aspect. As long as you leave them alone, they will do the same for you.
Are They Poisonous/Venomous?
Being a parasitoid wasp species, grass carrying wasps carry paralyzing venom that they use to immobilize their prey.
Don’t get worried, though; the venom is too weak to have any effect on humans. Besides, they don’t use the venom on anyone besides their prey anyway.
Are They Harmful or Beneficial to Humans?
Despite the general notion that wasps are dangerous, most of them are beneficial insects. The grass carrying wasp is no exception either.
Firstly, grass carrying wasps are amazing pollinators. Farmers often lure them to their gardens or agricultural fields by providing nesting places.
Secondly, these black wasps also help control pest populations by hunting them down to provide food for their larvae.
What Are Grass Carrying Wasps Attracted To?
Since adult grass carrying wasps feed primarily on pollen and nectar, they are attracted to flowering plants. As mentioned earlier, they have a preference for certain flowers like goldenrod, mountain mint, boneset, etc.
You may also attract them to your garden by installing bee hotels or simply digging small holes where they can nest.
Removing Grass Carrying Wasps
There’s no need to get rid of grass-carrying wasps unless the nest location is causing you inconvenience or puts you at risk of getting stung.
If you must remove grass-carrying wasps from your property, simply removing the nest should usually be enough.
It warns the wasps that the spot is unsafe for nesting, prompting them to go elsewhere.
If they persist and keep returning, you may consider using a pesticide. However, stick to low-toxicity pesticides that are safe for residential use.
Bug Control Recommendation Tool
Interesting Facts About Grass Carrying Wasps
Before we conclude this article, here are some interesting tidbits about grass-carrying wasps.
- Despite being capable of delivering a painful sting, these wasps are generally harmless to humans.
- Unlike most solitary species of wasps, grass-carrying wasps don’t usually build their nests underground.
- These wasps are native to North America, so there’s a good chance you might come across them.
Wrapping up
Social wasp species like paper and yellow jacket wasps are feared due to their aggressive nature and painful stings, but the grass-carrying wasps are nowhere near as dangerous.
They are more like female digger wasps—harmless unless you bother them.
So, the next time you see a wasp carrying a blade of grass or tucking it into a hole, there’s no need to panic. Thank you for reading, and I hope you found this article helpful.
References
Michigan State University Extension. (2020). The grass-carrying wasp: A solitary wasp that builds an unusual nest. Retrieved June 26, 2024, from https://www.canr.msu.edu/news/the_grass_carrying_wasp_a_solitary_wasp_that_builds_an_unusual_nest
Penn State Extension. (2023). Grass-carrying wasp. Retrieved June 26, 2024, from https://extension.psu.edu/grass-carrying-wasp
Iowa State University Extension and Outreach. (2016). Grass-carrier wasp. Retrieved June 26, 2024, from https://yardandgarden.extension.iastate.edu/grass-carrier-wasp
Frequently Asked Questions
Why are wasps flying around my grass
There could be various reasons why wasps are flying around your grass. One reason could be that there is a nest nearby, and the wasps are searching for food or gathering materials to build their nest.
Another reason could be that there are flowers or plants in your grass that are attracting the wasps.
Wasps are also attracted to sweet and sugary substances, so if there are any spilled drinks or food in the area, the wasps may be attracted to it.
It is important to be cautious around wasps as they can sting and cause allergic reactions in some people. It is best to avoid disturbing any nests and to keep food and drinks covered when outside.
What are some fun facts about common wasps?
Common wasps, also known as yellow jackets, are one of the most aggressive species of wasps.
They are known for their painful stings, which can be life-threatening to people who are allergic to their venom. However, there are some fascinating facts about these insects.
For example, yellow jackets are social insects that live in large colonies. The queen wasp is the only one who lays eggs, and the other members of the colony are responsible for feeding and protecting the queen and her offspring.
Yellow jackets are also known for their love of sweets, and they are often seen buzzing around picnic tables and garbage cans in search of sugary treats.
Interestingly, yellow jackets are not always yellow; some species have black and white markings, while others have red and black stripes.
What do wasps fly around looking for?
Wasps fly around looking for food and nesting material. They are carnivorous insects and feed on other insects, spiders, and some sugary substances like nectar and fruit juices. In the late summer months, wasps become more aggressive in their search for food, as they need to stockpile enough food to survive the winter. Wasps also fly around looking for suitable places to build their nests. They prefer sheltered areas such as under eaves, in attics or sheds, or in trees and bushes. Once they find a suitable spot, they will start building their nests using materials like chewed-up wood fibers, mud, and saliva.
What is the meaning of wasp nest?
A wasp nest is a structure created by social wasps to house their colony. It is typically made of a paper-like material that the wasps create by chewing wood and mixing it with saliva. The shape and size of the nest can vary depending on the species of wasp, but they are usually round or oval and have a small entrance hole. Wasp nests can be found in a variety of locations such as trees, bushes, eaves of buildings, and underground. While wasp nests can be fascinating to observe, it’s important to exercise caution as wasps can be aggressive and their stings can be painful or even deadly for those who are allergic.
26 Comments. Leave new
I found a couple of these nests yesterday and cleaned them out. One reappeared today and I took pictures and posted on Facebook. Somebody said they were katydids and, through looking for them, found your site. It’s wonderful when the answers just appear. Thank you!
We are happy to learn our site was helpful.
We just cleaned these nests out of 2 storm window tracks and we were thinking they were stink bug nests. Glad to ID the critter finally from you site and others….
Thank you.
Veronica
We just cleaned these nests out of 2 storm window tracks and we were thinking they were stink bug nests. Glad to ID the critter finally from you site and others….
Thank you.
Veronica
PS: We are in Rochester, NY as well -the capital of grass-carrying wasps, I guess !
I love watching these little ladies. I have a windchime just outside my kitchen window and enjoy watching her progress. Go girl!
Apparently these wasps have migrated to Texas, it has been in the high 90’s here.
We recently replaced all our windows, in one of the frames we found this grassy nest, one solitary wasp flying about as we cleaned off lots of green tree crickets and grass !
The BugGuide distribution map has Grass Carrying Wasps found coast to coast in North America.
Apparently these wasps have migrated to Texas, it has been in the high 90’s here.
We recently replaced all our windows, in one of the frames we found this grassy nest, one solitary wasp flying about as we cleaned off lots of green tree crickets and grass !
Is there anything I can use on my window strips to keep these wasps from making a nest? I am thinking of a strong odor type of soap that can be rubbed onto the rubber tracks that will deter these wasps from building a nest. I use my air from early spring into late summer. It is such a chore to clean my screens and window tracks every time I open the windows in the fall. I keep hoping each season I will be surprised and not have to deal with this.
I am not a fan of any type of insect and hate having to clean this unsightly mess.
Any kind of help will be appreciated!
Eileen Manion
Pearl River, NY
Is there anything I can use on my window strips to keep these wasps from making a nest? I am thinking of a strong odor type of soap that can be rubbed onto the rubber tracks that will deter these wasps from building a nest. I use my air from early spring into late summer. It is such a chore to clean my screens and window tracks every time I open the windows in the fall. I keep hoping each season I will be surprised and not have to deal with this.
I am not a fan of any type of insect and hate having to clean this unsightly mess.
Any kind of help will be appreciated!
Eileen Manion
Pearl River, NY
I saw a black wasp with grass fly up under a wooden shingle. Will the wasp destroy the wood?
No.
Wanted to thank you for posting this. I had this issue this week and had no idea what was building the nest. I did see some wasp activity but never heard of grass carrying wasps before.
I just cleaned our first floor casement windows, and this is exactly what I found! Found at least 4 nests, some with the larvae still present. We are in Rochester, NY as well.
I live in Vancouver WA and for the first time in my 50 years of experience, I have this wasp making its grass nest inside my hanging pipe wind chimes. Are they supposed to live in my state? Is this an anomaly?
Thanks 7/2018
Based on sightings reported to BugGuide, Grass Carrying Wasps are found throughout North America, including Washington and British Columbia.
Sadly, my grass carrying wasp’s nest was destroyed by another flying insect, something mostly black with a band of white. Definitely not a bald faced hornet, this predator is mostly black, flies similar to a moth. I am kinda upset about this. I really enjoyed watching her build her nest. She seems to be back at though, as is the predator.
Curious. We wonder what that might be.
Is there a bug spray I can use to prevent the grass wasps from building in my window cracks?
Thank you for this information. I am cleaning all my windows and in every one found these nests. I can’t believe how many there are, up and down the whole track of the screen. And now I also know what a tree cricket is! Truthfully, I feel bad about destroying their nests. Have a nice day.
I am amazed! I had new windows installed in the spring this year, and ever since have been trying to figure out how the grass and bugs keep getting there! I have taken pictures and looked all over the place and finally found the answer here on your website! Now I need to figure out how to keep them from building nests here in the first place! I can finally open my windows but they are now filled with larva, bugs and grass! Thanks for the information!
Wow! Rochester NY here too! July 5th 2020 – 90 degree day.this nest showed up with in 24hrs!
Just found this nest in my screen door. Looks gross!
I killed mine with hairspray. Then pulled it out as one hairspray clump. Garbage! ewww.
Wow! Rochester NY here too! July 5th 2020 – 90 degree day.this nest showed up with in 24hrs!
Just found this nest in my screen door. Looks gross!
I killed mine with hairspray. Then pulled it out as one hairspray clump. Garbage! ewww.
I just found these nest with green katyids in our windows here in Oregon. It’s the first time I’ve run across them–dozens of paralyzed victims. As I cleaned the windows and washed the grooves clean, a wasp appeared and picked up a katyid, then flew away with it.
We have these…my cousin read my Facebook post and led me to your site!