Carrot Wasp: All You Need to Know for a Thriving Garden

folder_openHymenoptera, Insecta
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Carrot Wasps are fascinating insects belonging to the Gasteruptiidae family. Often found feasting on nectar and pollen on flowers in the carrot family, these wasps play a vital role in pollination.

Their distinct long, arched abdomen and noticeable neck contribute to their unique appearance. With 15 species in the genus in North America, these insects display a range of characteristics that make them an intriguing subject.

In addition to their appearance, Carrot Wasps are distinguishable by their enlarged tibias on their back legs.

Carrot Wasp

They are mostly black in color, and similarities between the species can make identification challenging for the untrained eye. However, their preference for visiting flowers like Wild Parsnip makes them more discoverable in the wild.

While they might seem intimidating due to their relation to stinging wasps, Carrot Wasps do not pose a threat to humans.

Instead, these solitary insects focus their energy on their ecological functions, such as pollination, making them an essential part of our ecosystem.

What Is a Carrot Wasp?

Species and Family

Carrot wasps belong to the Gasteruptiidae family, which consists of 15 species in North America. Five of those species can be found in the eastern region.

These wasps are commonly found on flowers in the carrot family, including wild parsnip.

Physical Characteristics

Carrot wasps have a unique appearance that helps distinguish them from other wasps:

  • Long, arched abdomen, similar to Ichneumon wasps
  • Noticeable neck
  • Tibias on back legs are enlarged

For easy comparison, here is a table highlighting the distinct features of carrot wasps:

FeatureCarrot Wasp
AbdomenLong and arched
NeckNoticeable
TibiasEnlarged on back legs

These physical characteristics make carrot wasps easily recognizable and differentiate them from other wasp species.

Carrot Wasp

Best Time for Observation

Carrot Wasps are typically observed during the summer months:

  • June
  • July
  • August

These wasps likely overwinter in the soil as pupae, emerging as adults in late spring and early summer.

Life Cycle and Behavior

Reproduction and Egg Laying

Carrot Wasps (Family Gasteruptiidae) have a unique reproductive behavior. Female wasps are equipped with a specialized organ called an ovipositor, which they use to lay eggs.

The ovipositor resembles a long, thin needle that extends from the abdomen. Females search for host eggs or larvae to parasitize by depositing their eggs inside or nearby.

Some characteristics of the female Carrot Wasp during egg-laying include:

  • Long, arched abdomen
  • Noticeable neck
  • Tibias on the back legs are enlarged

Larval and Adult Stages

Carrot Wasp larvae primarily feed on the host eggs or larvae in which they were laid, eventually consuming the host entirely.

As they mature, the larvae undergo several stages of development, called instars, before entering the pupal stage.

Adult Carrot Wasps, on the other hand, have differing feeding habits. They tend to be found eating nectar and pollen on flowers, especially those in the carrot family, like Wild Parsnip.

Unlike their parasitic larvae, adult wasps are not known to cause harm to plants or crops.

Here’s a comparison table of male and female Carrot Wasps features:

FeatureMale WaspsFemale Wasps
HeadLarge compound eyesSmaller compound eyes
ThoraxSlender and well-definedBroader and less defined
WaistNarrow and elongatedNarrow but thicker than male
AbdomenSmaller and cylindricalLarger and suitable for egg-laying

In summary, the life cycle of Carrot Wasps includes:

  1. Egg-laying by female wasps using their ovipositor
  2. Larvae feeding on host eggs or larvae
  3. Multiple instars as the larvae grow and develop
  4. Pupal stage
  5. Emergence of adult wasps that feed on nectar and pollen from flowers

Habitat and Distribution

North America

Carrot Wasps (family Gasteruptiidae) are usually found in areas with flowers from the carrot family, including Wild Parsnip. Native to North America, these insects are known for:

  • Feeding on nectar and pollen
  • Being attracted to flowers in gardens

There are 15 species of Carrot Wasps in North America, with five of them inhabiting the eastern part of the continent1.

Other Regions

Outside North America, Carrot Wasps inhabit other regions as well. While specific distribution details may vary, these regions generally share the following features:

  • Presence of flowers from the carrot family
  • Suitable habitat for wasps to thrive

Carrot Wasps play an essential role as pollinators, and their distribution may shift based on the availability of their preferred flora2.

Diet and Predation

Food Sources

Carrot Wasps (Family Gasteruptiidae) mainly eat nectar and pollen from flowers in the carrot family, including Wild Parsnip 1. Carrot Wasps also play a crucial role in the ecosystem as pollinators.3

Examples of food sources:

  • Wild Parsnip flowers
  • Aphids
  • Caterpillars

Hunting Techniques

While feeding on nectar and pollen, they hunt for insects like caterpillars and aphids4.

Hunting techniques include:

  • Searching for prey while feeding on flowers
  • Using their long, arched abdomen to capture insects

Interaction with Other Insects

Relationship with Bees and Ants

Carrot Wasps share the same order, Hymenoptera, with ants and bees. All these insects play specific roles in nature.

Bees:

  • Primary pollinators
  • Visit flowers for nectar and pollen
Bees are social creatures

Carrot Wasps:

Ants:

  • Do not pollinate
  • Play roles in soil aeration and pest control

Carrot Wasps, bees, and ants exhibit differences in their social structures.

Bees and ants form colonies, while carrot wasps are solitary wasps who prefer to live alone.

Parasitic Relationships

Carrot wasps as parasitoids by nature, as explained earlier. Parasitoid wasps are a critical component in biological control methods.

They lay their eggs on or inside another insect’s body, which eventually results in their host’s death.

Parasitoid wasps prey on various pests, significantly benefiting gardeners and farmers.

Examples of other parasitoid wasps:

Although Carrot Wasps belong to a different family (Gasteruptiidae) and may not exhibit similar parasitic behavior, understanding the interactions among different wasp families provides valuable insight into their ecological roles.

Do Carrot Wasps Cause Harm To Humans?

Carrot Wasps share the same habitat as carrot rust flies – they both lay their eggs on carrot plants. Due to this reason, some might assume that they are harmful to the carrot crops.

However, Carrot Wasps are not a major concern for gardeners since it’s the carrot rust fly larvae that damage roots and cause most of the problems.

Comparison Table

FeatureCarrot WaspCarrot Rust Fly
ClassificationFamily GasteruptiidaePsila rosae
HabitatAreas with carrot family plantsAreas with carrot family plants
Role in ecosystemPollinators, predatorsPests
Impact on carrot plantingMinimal, not considered a major pestDamaging, feed on roots and cause damage

Wasp Defense Mechanisms

Stingers and Venom

Carrot wasps are solitary and non-aggressive, and they rarely interact with humans. They sting primarily to capture prey, not in defense. They are harmless and do not sting.

Carrot wasps are mainly seen around flowers in the carrot family, such as Wild Parsnip. They might be mistaken for other wasps that can sting, such as sphecid wasps.

Ichneumon Wasps

Self-Defense Behavior

Carrot wasps exhibit self-defense behaviors in response to threats. Examples of such behaviors are:

  • Flying away from potential threats
  • Using their stingers and venom when necessary
  • Mimicking other, more aggressive, wasps in appearance

Conclusion

In conclusion, Carrot Wasps, belonging to the Gasteruptiidae family, are captivating insects with their unique physical attributes like a long, arched abdomen and enlarged tibias on their back legs.

Their preference for flowers in the carrot family underscores their ecological importance in pollination.

While their adult life sees them mostly feeding on nectar and pollen, their parasitic larvae play a different ecological role.

Understanding the behavior and characteristics of Carrot Wasps not only satiates our curiosity but also accentuates the intricate ecological interactions within our gardens and wild landscapes.

Footnotes

  1. https://uwm.edu/field-station/carrot-wasp/ 2 3 4 5 6

  2. https://www.fs.usda.gov/wildflowers/pollinators/animals/wasps.shtml

  3. https://extension.umd.edu/resource/predatory-wasps 2

  4. https://extension.illinois.edu/blogs/garden-scoop/2021-06-12-wild-carrot-family-full-harmful-plants

Reader Emails

Over the years, our website, whatsthatbug.com has received hundreds of letters and some interesting images asking us about carrot wasps. Scroll down to have a look at some of them.

Letter 1 – Possibly Carrot Wasp from Australia

Subject: What insect is this?
Location: Centennial Park, Sydney, Australia
April 20, 2014 6:04 am
Hi there,
I came across this insect by some flowers in Centennial Park, Sydney, Australia. I can’t say I’ve seen anything like it, so I thought I’d see if you know. Thanks.
Signature: Chris

Possibly Carrot Wasp
Possibly Carrot Wasp

Dear Chris,
Of this we are certain:  This is a parasitic wasp that is classified as Parasitica or Parasitic Apocrita, which is not a true taxonomic category, but it is a means to group parasitic wasps together.  We believe it is a Carrot Wasp in the family Gasteruptiidae, which we identified on BugGuide, and then verified on the Atlas of Living Australia as being a family that is found in Australia. 

We may be wrong, but the look of the hind legs and the antennae as well as the ovipositor are good indications that we are correct.  According to BugGuide:  “Larvae are predators or predators-inquilines (consume larval food, not the larvae) of other Hymenoptera that nest in twigs and in wood.” 

The Atlas of Living Australia notes:  “Females oviposit in the nests of solitary bees (Apidae) and wasps (Vespidae) , where the larvae are predator-inquilines, eating the host egg or larvae and consuming the pollen store. Adult gasteruptiids may be seen on flowers or hovering near bare ground, logs or trees.”

Letter 2 – Carrot Wasp

So sorry to send so many
Location: Hawthorne, CA
August 29, 2011 6:14 pm
Hi,
Here is one that is on a flower that I haven’t been able to identify. I do know that it’s tiny flowers go to seed much as a dandelion. Guess I should pull it up right away if I don’t want my whole garden to be taken over. Just wanted to wait until I could get a somewhat decent photo of this tiny guy.

Can you help? I’m sending a photo of a bloom with a Mexican Sunflower leaf behind it so you can get an idea of the size. We know you’re very busy right now, but would appreciate any help you can give.
Anna
Signature: Thanks, Anna Carreon

Carrot Wasp

Hi Again Anna,
We actually identified this one much more quickly than we anticipated.  We opened the digital photo up yesterday before we did any research and this morning we zeroed in on the Carrot Wasps in the genus
Gasteruption on BugGuide

There is not too much information on the information page on BugGuide, except the unexplained common name Carrot Wasp and this statement regarding food:  “Adults take nectar; larvae are predators or predator-inquilines of other Hymenoptera that nest in twigs or other woody sites.” 

We suspect the adults are fond of taking nectar from the umbel blossoms of carrots and related plants, including many herbs like parsley, dill, and anise.  Your specimen is a male, as he lacks the ovipositor of the female. 

This Cirrus Images website has some beautiful photographs and from there we were directed to the Tree of Life website that more thoroughly covers the parasitic habits of the group.

Daniel,
Thanks very much!  This is such a small wasp and is very hard see, much less get in focus.  I’m so glad you were able to identify it for me.  I also appreciate the links to Cirrus Images & Tree of Life websites.
Anna

Letter 3 – Carrot Wasp from England

Subject: Is this an Ichneumon?
Location: Dorset, England
June 30, 2013 12:16 pm
Hi,
I would be grateful to kniow if this is an Ichneumon? We pictured it in our garden yesterday afternoon in Dorset, England. The body was about 1 cm long, very delicate, plus the length of the probe. It was a very light insect which went off on the wind shortly after the picture was taken.
Kind regards,
Bob Bentley
Signature: Bob Bentley

Carrot Wasp
Carrot Wasp

Dear Bob,
This is a Parasitic Hymenopteran, but it is not an Ichneumon.  We quickly found this image of a Carrot Wasp in the genus
Gasteruption on BugGuide, and we figured we had nailed your identification request, but then we realized you were from England.  BugGuide indicates: 

“Adults take nectar; larvae are predators or predator-inquilines of other Hymenoptera that nest in twigs or other woody sites” and “Gasteruption have a characteristic hovering flight with the swollen metatibiae hanging down so that the insect resembles a helicopter carrying a large load on a cable.” 

Nature Spot reports the species Gasteruption jaculator in England and notes:  ” The female will visit the nests of various solitary bees or wasps, and will push her ovipositor into the nest, depositing her own eggs on or near to the eggs of the host, on hatching they will feed on the grubs of the host as well as on stored food.” 

We are not certain if the common family name of Carrot Wasp is used in England.

Thank you so much Daniel.  Always nice to know we have a parasitic hymenopteran on the premises, it’s definitely one up on the neighbours!!!
Thanks again,
Bob

Letter 4 – Carrot Wasp from the UK

Subject:  Weird flying bug
Geographic location of the bug:  West Yorkshire UK
Date: 06/23/2018
Time: 05:06 AM EDT
Your letter to the bugman:  Hi this was in my garden this sunny morning, any clue what it is?
How you want your letter signed:  Sam

Carrot Wasp: Gasteruption jaculator

Dear Sam,
We found your parasitic Hymenopteran pictured on Nature Spot where it is identified as
Gasteruption jaculator.  According to the site:  “The female will visit the nests of various solitary bees or wasps, and will push her ovipositor into the nest, depositing her own eggs on or near to the eggs of the host, on hatching they will feed on the grubs of the host as well as on stored food.” 

The Game and Wildlife Conservation Trust has this lengthy description of the process:  “The female finds nests of various solitary bees or wasps, and will then spend some time assessing each hole.

She does so, it is thought, by feeling for vibrations from the grubs moving around inside, as the nest hole will have been blocked up to protect the grubs. Having decided on a suitable nest hole, she pushes her long ovipositor through the blocked-up entrance into the nest, depositing her own eggs next to the bee grubs.

Very soon the eggs hatch and immediately the young start to feed on the grubs within the nest. They will also consume the food larder of pollen and nectar, left there for the bee grubs to feed on.  The fully grown larvae stay in the bee hole over winter, pupating in the spring and hatching out from May through to September, so they can be seen throughout the summer months, nectaring on a range of plants.

This long summer hatching period enables the female to choose a wide range of solitary bee and wasp hosts to target for raising her own offspring, ensuring that her eggs are quite literally not all in the same basket.

It also means that they can, to a certain extent, avoid being attacked themselves by other parasites, which might be the case if they all hatched at the same time.”  Neither of those sites provides a common name, but the collective common name on the North American site BugGuide is Carrot Wasp.

Authors

  • Bugman

    Bugman aka Daniel Marlos has been identifying bugs since 1999. whatsthatbug.com is his passion project and it has helped millions of readers identify the bug that has been bugging them for over two decades. You can reach out to him through our Contact Page.

    View all posts
  • Piyushi Dhir

    Piyushi is a nature lover, blogger and traveler at heart. She lives in beautiful Canada with her family. Piyushi is an animal lover and loves to write about all creatures.

    View all posts
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