Red Humped Caterpillar: Essential Guide for Curious Minds

The Red Humped Caterpillar is a fascinating insect known for its distinct appearance and feeding habits. Its striking features include a dull red head and a similarly colored hump on the first abdominal segment, which is the reason behind its name. The body of this caterpillar is a yellowish color adorned with black and white stripes, giving it a unique look among caterpillars source.

These caterpillars go through four stages of development: egg, larva, pupa, and adult moth. Typically, moths emerge from their pupae between April and May, mate, and then lay their eggs on host foliage. Once hatched, the Red Humped Caterpillar larvae feed on and chew leaves, and are known to feast on trees and plants in orchards and gardenssource. In most cases, regular pest control measures are sufficient to minimize damage caused by these creatures. However, severe infestations might require the use of selective insecticides or other interventions source.

Red Humped Caterpillar Identification

Physical Characteristics

The Red Humped Caterpillar, known scientifically as Schizura concinna, is a larva with distinctive features that set it apart from other caterpillars. The following are some key characteristics:

  • Head: Dull red color
  • Body: Yellowish, with black and white stripes
  • Tubercles: Black tubercles on the top of several body segments
  • Hump: Reddish hump on the first abdominal segment, right after the thorax

These features make the Red Humped Caterpillar easy to identify, particularly the red head and the prominent red hump on its first abdominal segment.

Moth Stage

The adult stage of the Red Humped Caterpillar turns into the Red-humped Caterpillar Moth. Here are some notable features:

  • Wingspan: 1-1.5 inches
  • Forewings: Grayish brown with a slight gloss
  • Size: Females are larger than males

A brief comparison of the larva and adult stages:

Stage Size Color Notable Features
Larva 1-1.5 inches Red head, yellow body with black and white stripes Red hump, black tubercles
Adult 1-1.5 inches wingspan Grayish brown Glossy forewings, size difference between males and females

The Red Humped Caterpillar goes through a complete four-stage development process: egg, larva (caterpillar), pupa, and adult (moth). This transformation from a distinctly colored larva to a grayish-brown moth showcases the fascinating life cycle of this insect.

Life Cycle and Habitat

Egg Stage

The red-humped caterpillar’s life cycle starts with eggs laid by adult moths. The eggs are typically tiny and laid in groups on the leaves of host plants.

Larval Stage

Upon hatching, the caterpillars grow into an inch to 1-1/2 inches in size. They have a distinctive dull red head and a red hump on the first abdominal segment (source). Their body is yellow with black and white stripes, and they have black tubercles on several body segments.

Cocoon and Pupa Stage

As they reach maturity, the caterpillars form a cocoon in which they undergo a stage called pupa. The cocoon is typically seen in the topsoil or organic debris and is brown to red in color (source). The pupa stage is a significant transformation period before adulthood.

Adult Stage

Adult red-humped caterpillars emerge as moths around April to May. The moths are small, with a wingspan of 1-1.5 inches. Females are generally larger than males (source).

Habitat:

  • Native to North America, specifically eastern areas.
  • Found in Canada and the United States.
  • Part of the Lepidoptera order and Notodontidae family.

Characteristics:

  • Distinct red hump on the first abdominal segment.
  • Yellow body with black and white stripes.
  • Black tubercles on several segments.

Life Cycle:

  1. Egg stage
  2. Larval stage
  3. Cocoon and pupa stage
  4. Adult stage (moth)

Host Plants and Damage

Common Host Plants

Redhumped Caterpillars are known to infest:

  • Fruit trees like plum, apple, apricot, pear, cherry, and almond.
  • Deciduous trees such as willow, birch, walnut, cottonwood, liquidambar, sweet gum, and redbud.

Signs of Infestation

  • Skeletonized leaves with only veins remaining.
  • Partial or complete defoliation of branches and tree canopy.

Impact on Trees and Foliage

Defoliation: Redhumped caterpillars can cause significant damage to host trees and plants.

  • They feed on the foliage, often skeletonizing leaves, leaving behind only the veins.
  • Severe infestations can result in complete defoliation.

Impact on Fruit: Fruit trees may have reduced yield due to foliage loss, as leaves are responsible for photosynthesis.

Tree Health and Regrowth:

  • Providing trees with proper care can increase their tolerance to caterpillar damage.
  • Healthy trees are more likely to recover from infestations and regrow leaves.

Management and Control:

  • Regular monitoring of trees is important to detect infestations early.
  • Use targeted interventions, such as Bacillus thuringiensis, or broad-spectrum insecticides, to control caterpillar populations in severe cases. For more information on interventions, refer to Integrated Pest Management guidelines.
  • Removing affected branches can help reduce caterpillar numbers.

Comparison Table:

Redhumped Caterpillar Other Caterpillars
Host Plants Fruit and deciduous trees Varies by species
Signs of Infestation Skeletonized leaves, defoliation Varies by species
Impact on Trees Reduced foliage and fruit yield Varies by species

Natural Predators and Biological Control

Parasitic Wasps

A key aspect of the Redhumped Caterpillar’s natural predators are parasitic wasps. One example of a parasitic wasp is the Apanteles genus, which targets caterpillars in their early stages. The wasps lay their eggs in the caterpillars, and upon hatching, consume their host from the inside.

Pros of parasitic wasps:

  • Effective in reducing caterpillar populations
  • Natural and chemical-free approach

Cons of parasitic wasps:

  • Can take time for the wasp population to control caterpillars
  • May affect other caterpillar species

Insects and Arachnids

In addition to parasitic wasps, numerous other insects and arachnids prey on Redhumped Caterpillars. These include ants, beetles, spiders, damsel bugs, and lacewings.

Ants, beetles, and spiders:

  • Aggressive predators
  • Easily found in natural environments

Damsel bugs and lacewings:

  • More specialized feeders
  • Contribute to caterpillar population control

Birds

Many bird species find Redhumped Caterpillars to be an appetizing meal. Birds help maintain balance in the ecosystem by keeping caterpillar populations in check. By consuming these pests, birds indirectly protect plants from extensive damage.

Management and Treatment

Monitoring

To manage red humped caterpillars effectively, it is crucial to monitor their populations. This includes looking for signs such as leaf damage and caterpillar presence. Moths of America North of Mexico, a publication on pests, can provide information on monitoring techniques.

Chemical Control

When dealing with severe infestations, insecticides are useful. Two common insecticides used for controlling red humped caterpillars include:

  • Bacillus thuringiensis (Bt): A natural, bacteria-based insecticide that targets caterpillars specifically.
  • Spinosad: Another effective, organic insecticide for controlling caterpillars.
Insecticide Pros Cons
Bacillus thuringiensis (Bt) Targets caterpillars specifically, environmentally friendly May require multiple applications
Spinosad Effective organic control, low toxicity to humans Harmful to beneficial insects

Organic Control

For an environmentally friendly approach, consider organic control methods such as:

  • Parasitic wasps: These natural predators of red humped caterpillars can help keep their population in check.

Physical Control

Physical control methods are also effective. Some examples include:

  • Removing infested twigs: This can minimize the caterpillar’s impact on the plant.
  • Pruning in winter: Removing eggs and larvae during winter helps prevent new infestations in the following seasons.

These strategies, combined with the right treatment, can provide effective control of red humped caterpillar populations.

Caterpillar Safety and Human Impact

Handling Precautions

When interacting with red humped caterpillars, be cautious as their appearance includes features such as:

  • White stripes
  • Orange body
  • Red eyes
  • Black spines

It is best to avoid handling these caterpillars to prevent potential skin reactions, as their black spines can cause irritation. Use gloves to protect your skin if you need to remove them from your property.

Potential Skin Reactions

Coming into contact with the spines of the red humped caterpillar might cause a rash or other skin reactions. These caterpillars have yellowish bodies with black spines, which contain urticating hairs that can trigger itching and irritation. If you notice symptoms, immediately wash the affected area with soap and water.

Comparison between red humped caterpillar and a less harmful caterpillar:

Feature Red Humped Caterpillar Less Harmful Caterpillar
Stripes White Absent
Body Color Orange, yellowish Green
Eyes Red Absent
Spines Black Absent
Potential for skin reaction Yes No

In conclusion, always exercise caution when dealing with red humped caterpillars, taking necessary precautions and being mindful of potential skin reactions.

Reader Emails

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

Letter 1 – Red Humped Caterpillar

 

Caterpillars feeding on speckled alder
Fri, Nov 7, 2008 at 1:14 PM
Hi!
I really like your website – it’s been very helpful in identifying many of the insects that I’ve found. These caterpillars I’m having a hard time with though. I saw them during the summer, munching on speckled alder leaves on an island in Georgian Bay. As you can see in the photograph, they are yellow, black and white striped, with reddish orange heads and a big reddish bump a little ways behind the head as well. They have several hairs and stiff black spikes along them. Do you know what they are?
Kristin
Georgian Bay, Ontario, Canada

Red Humped Caterpillars
Red Humped Caterpillars

Hi Kristin,
It took us a bit of searching before we were able to identify your Red Humped Caterpillars, Schizura concinna, but we eventually located it on BugGuide where it is described as:  ” has bright red head and red hump over segment A3.  Striping is variable but includes black, yellow and white pinstripes.  Takes up a defensive posture raising the rear end when disturbed. ” This is a Prominent Caterpillar in the family Notodontidae.

Letter 2 – Red Hump Caterpillar

 

Caterpillar on Western Redbud
September 21, 2009
Caterpillar on Western Redbud
2 feeding this afternoon in the hot California sun
J serences
Carmichael CA Central Valley

Red Hump Caterpillar
Red Hump Caterpillar

Hi J,
We believe this to be a Red Hump Caterpillar, Schizura concinna, a species of Prominent Moth.  The caterpillars, according to BugGuide:  “feed on a wide range of woody plants.

Letter 3 – Red Humped Caterpillar

 

what is this?
Location: Sacramento, CA
November 9, 2010 12:01 am
Hello there,
Three of these caterpillar/larva are on my deck. I have never seen anything like them before. I took the picture. Also, what is that reddish orange part that isn’t the head? Hope you can help.
Signature: MaryLynn

Red Humped Caterpillar

Dear MaryLynn,
Knowing where to begin a search is often very helpful.  We thought your caterpillar resembled a Prominent Moth Caterpillar in the family Notodontidae, and we were quickly rewarded while searching BugGuide with the Red Humped Caterpillar,
Schizura concinna, a species found coast to coast in North America.  The “reddish orange part that is not the head” is the hump, though we cannot say for certain what its purpose is.

Wow! You guys are sure prompt. Many thanks, Daniel.
ML

Letter 4 – Red Humped Caterpillar

 

Subject: What is this caterpillar?
Location: Similkameen valley British Columbia canada
October 18, 2013 7:09 pm
This caterpillar was found on young apple trees at the beginning of August in the Similkameen valley, British Columbia, Canada. We are wondering what it is. Please help.
Signature: Orchardist

Red Humped Caterpillar
Red Humped Caterpillar

Dear Orchardist,
Is that an apple leaf?  this appears to be a Red Humped Caterpillar,
Schizura concinna.  According to BugGuide:  “Larvae feed on a wide range of woody plants, from many different families.”

Red Humped Caterpillar
Red Humped Caterpillar

thank you so much.
Yes it was on apple leaves…several neighbours have found them too and as
much as I tried I cold not identify it. Now we know!

 

Letter 5 – Red Humped Caterpillar

 

Subject: blueberry defoliator
Location: Jaffrey, New Hampshire
September 10, 2015 8:37 pm
One of my blueberry bushes had a bunch of these
Signature: Doug

Red Humped Caterpillar
Red Humped Caterpillar

Dear Doug,
Your caterpillar is
Schizura concinna and it goes by the very descriptive name Red Humped Caterpillar.  According to BugGuide:  “Larvae feed on a wide range of woody plants, from many different families.”  Interestingly, we have not found any other mention of Red Humped Caterpillars feeding on blueberries.

Thank you Daniel!  That was a bunch of very impressive caterpillars and they finished the job on that poor blueberry.

Letter 6 – Red Humped Caterpillar

 

Subject: Unknown caterpillar consuming Indigobush & Serviceberry
Location: Reston VA
September 28, 2015 5:52 pm
Please identify a caterpillar for me and if it’s a butterfly or moth; 3 pictures attached. Many of the same caterpillar are consuming an Indigobush and have moved on to a nearby Serviceberry.
Signature: Margaret Grieshaber

Red Humped Caterpillar
Red Humped Caterpillar

Dear Margaret,
Your Red Humped Caterpillar,
Schizura concinna, will become a moth in the family Notodontidae.   According to BugGuide, Red Humped Caterpillars:  ” feed on a wide range of woody plants, from many different families.”

Dear Daniel – Thank you very much for a quick reply!  Believe we’ll just let it happen and not do anything to disturb them. Thanks again, Margaret

Letter 7 – Red Humped Caterpillar

 

Subject:  Unidentifiable CaterpillarS
Geographic location of the bug:  Roseville, CA
Date: 11/12/2019
Time: 06:41 PM EDT
Your letter to the bugman:  Can you tell me what this is?  They denuded my redbud tree. How can I prevent them from returning. Organic pesticides had no effect whatsoever. Thank you.
How you want your letter signed:  Sharon

Red-Humped Caterpillar

Dear Sharon,
This is a Red-Humped Caterpillar,
Schizura concinna, which you can find pictured on BugGuide.  According to the University of California Integrated Pest Management site:  “Young caterpillars commonly feed side-by-side in groups, chewing on the lower leaf surface. As the larvae grow, they tend to disperse and feed in smaller groups or individually. Skeletonized leaves are a common result, as the older caterpillars chew all the way through and consume leaves, leaving only the larger, tough veins. … When their abundance is low, larvae eat leaves on only a few branch terminals. Occasionally, heavy infestations develop and defoliate entire trees during the summer. Usually only scattered individual and young trees are severely defoliated. If severely defoliated, trees that are otherwise healthy usually recover.”

Dear Daniel,
Thank you for the quick response and valuable information about the Red-Humped Caterpillars.  They are scary-looking. I hope my redbud tree will recover. Thanks again!

Letter 8 – Red Humped Caterpillar

 

Subject:  Caterpillar identification
Geographic location of the bug:  northern Ontario, Canada
Date: 08/08/2021
Time: 08:47 PM EDT
Your letter to the bugman:  Please help me to identify this little guy. I saved him from my kitty, and well certain death. Please help?
How you want your letter signed:  Ms. Tara Lilian

Red Humped Caterpillar

Dear Ms. Tara Lilian,
This is a Red Humped Caterpillar,
Schizura concinna, and according to BugGuide:  “Larvae feed on a wide range of woody plants, from many different families.”

Letter 9 – Red Humped Caterpillars

 

Caterpillar grouping
Location: Sioux Lookout, NW Ontario
August 1, 2011 1:29 pm
Hi! I’ve been seeing these caterpillars in groups each summer and wonder what they are….I’d like to show them to my preschool class but would like to know what they are first (since they will almost certainly ask!).
Thanks
Signature: Mike Lawrence

Found him through your site, many pages in…Red Humped Caterpillar….Thanks !
Mike

Red Humped Caterpillars

Hi Mike,
We are very happy to learn that you were able to self-identify your Red Humped Caterpillars,
Schizura concinna, by browsing through our archives.  As far are requests go, summer is the busiest time of year for us and many requests go unanswered.  More information on the Red Humped Caterpillar is available on BugGuide.

Letter 10 – Red Humped Caterpillars

 

Subject: cluster of caterpillers on sweet gum
Location: Brown County, Indiana
September 12, 2012 12:06 pm
Found this group of bugs I had never noticed before on a sweet gum tree in our yard in Southern Indiana.
No luck identifying them …
Signature: Crindi

Red Humped Caterpillars

Hi Crindi,
We know that we have identified these caterpillars in the past, but we had a brain freeze.  We also know how difficult it can be to try to identify caterpillars, and we didn’t want to spend hours in an identification pursuit, so we tried a web search of “caterpillars sweet gum” which quickly led us to the Forestry Images photograph of the Red Humped Caterpillars,
Schizura concinna.  Knowing the plant upon which a caterpillar or other insect is feeding is often a tremendous assistance during the identification process.  We have several photos of Red Humped Caterpillars on our site which is why they seemed so familiar to us.

Thanks!
I have used your site a couple times now and have made a donation for your expenses.
Chris Gustin

Thanks for your support.

Letter 11 – Red Humped Caterpillars

 

Subject: help caterpillers eating my tree
Location: northern cali- roseville, Ca
May 19, 2014 9:23 am
Hi. I sent a previous request. Didnt know if it went thru. No confirmation saying my pics were uploaded. So im trying again. I have these caterpillers eating my tree. I dont want to hurt them…but I dont want my tree to die or an ugly bald tree either. They just eat everything! And they poop alot too! I took a branch to the kids in my classroom to observe and it was fasinating how quickly they devour a whole branch. They are on my ornamental plum tree. Thanks for your help
Signature: Alma

Red Humped Caterpillar
Red Humped Caterpillar

Hi Alma,
Because of the red head and red hump, these Red Humped Caterpillars,
Schizura concinna, are quite distinctive.  According to BugGuide:  “Larvae feed on a wide range of woody plants, from many different families.”

Red Humped Caterpillars
Red Humped Caterpillars

Thank you Daniel for your e-mail!  The kids are loving watching them and now  we know exactly what they are.    We are hoping they will form chrysalis soon! Although the moth is not very pretty.
Alma

Letter 12 – Red Humped Caterpillars

 

Subject: what is this….
Location: Davis, CA
November 1, 2014 5:08 pm
Hello, Do you know what these are? They were found in our persimmon tree. Thanks.
Signature: No need

Red Humped Caterpillars
Red Humped Caterpillars

Dear No need,
These Red Humped Caterpillars,
Schizura concinna, ” feed on a wide range of woody plants, from many different families” according to BugGuide.

Letter 13 – Red-Humped Caterpillars

 

Subject:  Caterpillar eating blueberry bush
Geographic location of the bug:  Wales, Maine
Date: 08/25/2018
Time: 10:18 AM EDT
Your letter to the bugman:  Hello, Can you tell me what this caterpillar is?  I do not want it to eat the blueberry bushes but I don’t want to kill them either.
How you want your letter signed:  Amy

Red Humped Caterpillars

Dear Amy,
These are Red Humped Caterpillars,
Schizura concinna, and according to BugGuide:  “Larvae feed on a wide range of woody plants, from many different families” so it should be an easy matter to relocate the caterpillars, but alas, BugGuide did not provide a list of any particular preferred food plants.  According to the University of California Pest Management System:  “This pest most commonly chews leaves of liquidambar (sweet gum), plum, and walnut. It also feeds on almond, apple, apricot, birch, cherry, cottonwood, pear, prune, redbud, willow, and other deciduous trees and shrubs.”  The site also states:  “Young caterpillars commonly feed side-by-side in groups, chewing on the lower leaf surface. As the larvae grow, they tend to disperse and feed in smaller groups or individually. Skeletonized leaves are a common result, as the older caterpillars chew all the way through and consume leaves, leaving only the larger, tough veins. Unlike certain other caterpillars that may feed on the same hosts, redhumped caterpillars do not tie leaves with webbing or leave silk strands on foliage; the exception is when silk-covered pupae occur on leaves.  When their abundance is low, larvae eat leaves on only a few branch terminals. Occasionally, heavy infestations develop and defoliate entire trees during the summer. Usually only scattered individual and young trees are severely defoliated. If severely defoliated, trees that are otherwise healthy usually recover.”

Authors

    by
  • 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

5 thoughts on “Red Humped Caterpillar: Essential Guide for Curious Minds”

  1. So, this looks like what I am seeing all over my yard – they have never been here in the high desert of Joshua Tree, CA, but now they seem to be everywhere. My dogs want to eat them but I don’t know if they are poisonous. . . any info much appreciated!

    Reply
    • According to BugGuide data, they are found in California. According to BugGuide: “Larvae feed on a wide range of woody plants, from many different families.” That is circumstantial evidence that you have encountered Red Humped Caterpillars, but we are reluctant to identify a Caterpillar without seeing an image. You may submit an image by using the Ask WTB? link on our site. To the best of our knowledge, they are not poisonous.

      Reply
  2. I just found several of these intent on defoliating a wild blackberry cane! They’ve stayed out of the raised-bed garden nearby, thank goodness. Winston B., Louisa County, Virginia, USA

    Reply

Leave a Comment