Large Milkweed Bug: All You Need to Know in a Nutshell

The Large Milkweed Bug (Oncopeltus fasciatus) is an intriguing insect commonly found on milkweed plants, with striking orange and black markings that make it easily recognizable. The adult bugs are around ¾ inch long, featuring a distinctive black band across their back and preferring to feed on milkweed, particularly the seeds source.

Although Large Milkweed Bugs are not the only insects that rely on milkweed plants, they have a special relationship with this plant. These bugs are known to travel south for the winter source, highlighting their intriguing life cycle and adaptability. Stay tuned to learn more about this fascinating species as we delve deeper into their characteristics, life stages, and benefits or drawbacks to their host plants.

Large Milkweed Bug Basics

Scientific Name and Classification

The large milkweed bug is an insect belonging to the Hemiptera order and the Lygaeidae family. Its scientific name is Oncopeltus fasciatus.

Physical Description and Coloration

The large milkweed bug is known for its bold coloration and striking appearance. Some key features include:

• Reddish-orange body
• Black band across its back
• Black spots, patches, and antennae

Adults measure approximately ¾” long. The nymphs and adults of this true bug species have similar coloration but with different patterns.

Geographical Distribution

Large milkweed bugs can be found in various regions across North America. They are known to feed on milkweed plants, particularly the seeds, making them commonly found clustering on the plants’ seed pods¹. The large milkweed bug, like other milkweed feeders, travels south for the winter.

The Milkweed Plant Connection

Plant Species and Importance

Milkweed plants, belonging to the genus Asclepias, are essential for the survival of several insect species. Some common species include Asclepias syriaca and swamp milkweed. Milkweed provides:

• Leaves and stems: Nutritious food source for caterpillars
• Sap: Contains toxins acting as a defense mechanism for insects feeding on the plants
• Seeds: Rich food source for several species of insects

Milkweed plants hold importance for their role in supporting ecosystem biodiversity.

Relation to Monarch Butterflies

Milkweed plants have a special connection with monarch butterflies. Monarch caterpillars rely on milkweed leaves as their primary food source. As they grow, they ingest the sap, which contains alkaloid toxins. These toxins provide the caterpillars and adult butterflies with a defense mechanism against predators, as they become toxic to consume.

Comparison of Monarch Caterpillars and Large Milkweed Bugs

	Monarch Caterpillars	Large Milkweed Bugs
Diet	Milkweed leaves	Milkweed seeds, nectar
Habitat	Found on milkweed plants	Found on milkweed plants, especially pods
Toxins	Accumulate toxins by ingesting milkweed sap	Accumulate toxins by feeding on milkweed seeds

As monarch caterpillars and large milkweed bugs both rely on milkweed plants as a food source, their fates are intertwined. Preserving and protecting milkweed plants is vital for sustaining the populations of these species and maintaining their role in the ecosystem.

Life Cycle and Reproduction

Eggs and Clutch Size

Female Large Milkweed Bugs lay 25 to 35 eggs per day in small clusters¹. The eggs are:

• Light yellow initially
• Turn reddish before hatching

Nymphs and Juveniles

Nymphs undergo five instars before reaching adulthood². Key features of nymphs:

• They have wing pads, but not fully functional wings
• Resemble adults in color and pattern but smaller

Adults and Mating

Adults are reddish-orange with a black band and distinct patterns on their wings³. Males and females can be distinguished by their:

• Abdomen shape: Males have pointed abdomens, females have rounded ones⁴
• Size: Males are often slightly smaller than females

Large Milkweed Bugs exhibit incomplete metamorphosis⁵.

Seasonal Changes and Overwintering

These bugs overwinter as adults⁶. Key points about seasonal changes and overwintering:

• They migrate to warmer climates during winter
• They return to their original habitats when the weather starts warming up

	Nymphs	Adults
Wings	Have wing pads, not fully functioning	Fully functional wings
Overwintering	Do not overwinter	Overwinter as adults6
Reproduction7	Cannot reproduce	Capable of reproduction

Diet and Feeding

Herbivorous Diet

Large milkweed bugs (Oncopeltus fasciatus) have a specific diet focused on milkweed plants. They feed on various parts of the plant, mainly the seeds. These insects share the milkweed with other species such as monarch butterflies and milkweed tussock moths.

• Large milkweed bugs: Seed pods
• Monarch butterflies: Milkweed leaves
• Milkweed tussock moths: Milkweed leaves

Proboscis and Feeding Habits

These bugs have a unique mouthpart called a proboscis. They use it to pierce plant tissues and extract juices. Large milkweed bugs typically feed in groups, making them conspicuous to predators. Despite their bold appearance, they cause minimal harm to milkweed plants.

Feeding Features	Large Milkweed Bug
Mouthpart	Proboscis
Preferred plant part	Seed pods
Feeding in groups	Yes
Harm to milkweed	Minimal

Predators and Defense Mechanisms

Toxic Compounds and Aposematism

The Large Milkweed Bug (Oncopeltus fasciatus) acquires toxic compounds from its primary food source, the milkweed plant. These compounds, called cardenolides, provide them with a defense mechanism against predators¹. Their bright orange and black coloration serves as a warning sign, known as aposematism, to discourage potential predators from attacking them.

Common Predators of Milkweed Bugs

Despite their toxic defenses, some predators have adapted to consuming milkweed bugs, such as:

• Lady beetles
• Spiders
• Assassin bugs
• Praying mantises

While these predators do consume milkweed bugs, the overall population remains stable due to their effective aposematism and toxic compounds acquired from the milkweed plant².

Comparison Table for Defense Mechanisms

Defense Mechanism	Example	Effectiveness
Toxic Compounds	Cardenolides	High
Aposematism (Coloration)	Orange and black colors	High

• Toxic compounds: Acquired from milkweed plants, beneficial for deterring predators.
• Aposematism: Bold orange and black coloration serves as a warning sign to potential predators.

Large Milkweed Bug Interactions

Gardeners and Pest Control

Large milkweed bugs (Oncopeltus fasciatus) can be commonly found on milkweed plants, especially on the seed pods. These bugs feed on milkweed seeds, which may lead some gardeners to view them as pests in their gardens. However, they rarely cause significant damage to milkweed plants. Instead, consider these practices to control their population:

• Remove leaf litter
• Regularly check for eggs and nymphs
• Avoid using pesticide, which can harm beneficial species like monarch caterpillars

Impact on Ecosystem

In the ecosystem, large milkweed bugs have an important role:

• They help control the spread of milkweed
• Serve as a food source for birds and other insects
• Coexist with other milkweed feeders, like monarch caterpillars and aphids

Milkweed itself is important for pollinators, providing nectar and habitat.

Invasive Species

Large milkweed bugs are native to North America and are not considered invasive. They are most often found on milkweed along roadsides and in gardens. In comparison, small milkweed bugs(Lygaeus kalmii) have a red X-shape on their back and are also native to North America.

Species	Pattern on Back	Native/Invasive
Large Milkweed Bug	Black band with orange triangles	Native
Small Milkweed Bug	Red X-shape	Native

In summary, large milkweed bugs are beneficial insects that help control milkweed populations and maintain a healthy ecosystem.

Small Milkweed Bug Comparison

Differences in Appearance

• Small milkweed bug (Lygaeus kalmii): Grows up to ½ inch long, black with a large red X-shape on the back, white margins on the wings, and sometimes small white spots in the middle of the wings. There is a red band on the pronotum¹.
• Large milkweed bug (Oncopeltus fasciatus): Measures about ¾ inch long, orange to reddish-orange, with a black band across their back².

Habitats and Distribution

Both small and large milkweed bugs are true bugs that feed mainly on common milkweed plants. They share similar habitats and can be found on milkweed plants throughout North America¹². While they both feed on milkweed, their distribution and behaviors may vary slightly due to their size and specific preferences.

Feature	Small Milkweed Bug (Lygaeus kalmii)	Large Milkweed Bug (Oncopeltus fasciatus)
Size	Up to ½ inch long	About ¾ inch long
Color	Black with red X-shape	Orange to reddish-orange
Habitat	Common milkweed plants	Common milkweed plants
Distribution	Throughout North America	Throughout North America

Other Milkweed Inhabitants

Milkweed Beetles

Milkweed beetles are common inhabitants of milkweed plants. One example is the red milkweed beetle (Tetraopes tetraophthalmus) which is frequently found in Wisconsin source. Another example is the swamp milkweed leaf beetle. These beetles are identified by their segmented antennae and distinct coloration. They feed on milkweed leaves and can cause damage to the plants.

Aphids and Their Natural Enemies

Milkweed plants often attract oleander aphids. These small insects can infest the plants and cause damage by feeding on plant sap. However, milkweed plants benefit from the presence of certain beneficial insects that can help control aphid infestations. Examples of these beneficial insects include:

• Ladybugs
• Green lacewings
• Parasitic wasps

These insects feed on oleander aphids and can keep their populations under control, helping to protect milkweed plants from damage.

Assassin Bugs

Assassin bugs, specifically milkweed assassin bugs, are also found on milkweed plants. These insects are characterized by their:

• Elongated shape
• Curved, sharp mouthparts
• Pronotum (a shield-like structure behind their head)

Assassin bugs are considered beneficial insects because they feed on a variety of pests, including slugs, snails, mites, and other insects. They undergo simple metamorphosis, meaning that their juveniles look similar to adults, just smaller and without wings. A new generation of milkweed assassin bugs can help control pest populations on milkweed plants and contribute to a healthier ecosystem.

Footnotes

1. Good Growing ↩ ↩² ↩³ ↩⁴ ↩⁵

2. Milkweed Bugs, Large and Small (Family Lygaedidae) ↩ ↩² ↩³ ↩⁴

3. Large Milkweed Bug | Missouri Department of Conservation ↩

4. More than monarchs – What are those bugs on my milkweed? ↩

5. Milkweed Bugs, Large and Small (Family Lygaedidae) ↩

6. Common Milkweed Insects – Wisconsin Horticulture ↩ ↩²

7. Milkweed Bug | NC State Extension Publications ↩

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 – Milkweed Assassin Bugs: Red mantis-like bug with white spots

 

Greetings from Texas, Mr. Bugman!
I have recently found a colony of pretty little insects in my garden, but I don’t know what they are. They have the body that reminds me of a mantis without the bobbley head. The 3/4″ slender body is bright red with tiny white spots, and the legs and antennae are black. Hopefully these graceful looking little creatures won’t be harmful to my flower garden.
–De Smith
New Braunfels, TX

Dear De Smith,
My first inclination was to say you might have Assassin Bugs, probably nymphs. I cannot give an exact species. We just got a photo of a young assasin bug that fits your description rather accurately. Here it is. these are beneficial. They are predators that will eat harmful insects.

Yes!! That’s what we have in our garden. Thanks so much for your research!
–De

Letter 2 – Large Milkweed Bug from Australia

 

Subject: Bug identity, please?
Location: Kalbarri National Park, Western Australia
February 23, 2013 1:27 pm
The attached bug was about 10mm long, and on a handrail of an overlook. I have failed to identify it with Google images. It may be a nymph, I suppose. Any ideas will be really appreciated. Many thanks in advance.
Signature: Colin

Hi Colin,
We quickly identified this as a Large Milkweed Bug, Spilostethus hospes , on the Brisbane Insect website where it is classified as a Seed Bug in the family Lygaeidae.  The webmaster gives it the creative Star Wars reference name of Darth Maul Bug.  Save Our Waterways Now is in agreement with that identification, but does not refer to the name Darth Maul Bug.  Bold Systems Taxonomy Browser is also in agreement as is Australian Nature PHotography.  Encyclopedia of Life pictures other members in the genus.  The Entomology at Department of Agriculture Western Australia provides a better match with Spilostethus pacificus, though there is also a photo of a specimen of Spilostethus hospes that appears to be a narrower insect.   We then encountered a discrepancy on the Light Creations site where it is called a Hong Kong Stink Bug in the family Coreidae.

Hi,
Thank you so much for such a quick identification, and I’m sorry I’ve not had a chance before now to write back to you.
If you would like more details of the photograph of the Large Milkweed Bug (Spilostethus hospes), it was taken at 10.13am on the 3rd February 2013 at the coastal area of Kalbarri National Park, Western Australia.  The exact position was on the northern safety handrail of the Grandstand Lookout.
Regards,
Colin Butterworth

Letter 3 – Immature Large Milkweed Bugs feeding on Oleander

 

red bettle of some sort
Location: portland, tx
April 10, 2011 9:04 pm
Trimming oleanders today and came across these and I don’t know what they are. I live in Portland Texas, its spring time and found them all around. Not to bad though. Thanks for any info.
Signature: chris

Hi Chris,
We are very interested in your letter.  These are Large Milkweed Bug nymphs, Oncopeltus fasciatus, and as the name implies, they typically feed on Milkweed.  They are Seed Bugs and they feed by sucking the juices from the seeds which also contain the toxic sap.  Many insects that feed upon milkweed, including the Monarch Butterfly, store toxins that are found in the sap of the plant.  The toxins help to protect the insects from predators, and many such insects sport red and black warning colors like these Large Milkweed Bugs.  Oleander has similar qualities and insects that feed on the leaves of Oleander are similarly protected.  This is the first time we have heard of Large Milkweed Bugs being associated with Oleander, but a web search has uncovered an article published in Ecological Entomology entitled Nerium oleander as an alternative host plant for south Florida milkweed bugs, Oncopeltus fasciatus by EDWARD KLAUSNER, ELIZABETH RUTH MILLER, HUGH DINGLE.  Since we do not subscribe to the online Library, we cannot read the entire article, but this abbreviated abstract provides some fascinating information:  “1  Life history data were gathered for south Florida Oncopeltus fasciatus reared from eggs on Nerium oleander seeds and milkweed seeds in the laboratory.  2  Milkweed seeds were found to be a superior food source since O.fasciatus grew faster, laid more clutches, and has a higher total fecundity on milkweed seeds.  3  Fruiting N.oleander was found to be a better food source than nonfruiting milkweeds in a summer field study in south Florida since no nymphs survived to the adult stage on nonfruiting milkweeds but some did on N.oleander.  4  O.fasciatus adults and nymphs are abundant on N.oleander in the summer in south Florida when N.oleander is fruiting; no O.fasciatus nymphs are found in the summer on the milkweeds which are not fruiting.  5  O.fasciatus leave N.oleander in the autumn when milkweeds start to fruit and can then be found on fruiting milkweeds.”

thanks for the response.  My response is “Neat!”.  is there anything else I can provide for you about the plant or insect?

Thanks for the offer Chris, but since both plant and insect are identified, and we found a precedent for the unusual relationship, we cannot think of anything else we would require.  You may always add additional observations as comments to the posting.

Letter 4 – Large Milkweed Bug Nymphs

 

What is this bug
Location:  Akron, Ohio
September 26, 2010 8:47 pm
Any idea what this vibrant orange bug is. I was amazed at the different stages of life on one pod.
Signature:  Becki Caputo

Hi Becki,
There are two common species of Seed Bugs in the family Lygaeidae that feed upon the juices from the seeds of milkweed, and we believe your immature nymphs are Large Milkweed Bugs, Oncopeltus fasciatus based on comparing images of both species on BugGuide. Large Milkweed Bugs often form aggregations of numerous individuals while feeding, and you image shows two immature stages.  Adults have fully developed wings and they are able to fly.

Letter 5 – Mating Small Milkweed Bugs, NOT Kissing Bugs

 

Subject: Is this bug a “kissing bug”
Location: Albuquerque, NM
November 26, 2015 10:24 am
My daughter was playing with this bug, and I think may have a bite from it. I saw there is a CDC warning about kissing bugs, and wasnt sure if this was a kissing bug or not?
Signature: Lynn Foreman

Dear Lynn,
Though your image pictures them in an amorous position, these are mating Small Milkweed Bugs, not Kissing Bugs.  The images of the dead insect are also of a Small Milkweed Bug.

Thank you so much, that’s a big relief to me! Thank you for what you do!

Letter 6 – Mating Small Milkweed Bugs

 

Subject: Daniel – Mating Large Milkweed Bugs?
Location: Hawthorne, California
November 2, 2012 3:44 pm
Hello,
I was enjoying all of the different creatures on the Mexican Milkweed today and took these photos of what I assumed are Large Milkweed bugs. When I got them onto the computer and compared them to other photos, they don’t look quite the same.
Hoping you can confirm my sighting or let me know what they actually may be!
Signature: Thanks, Anna Carreon

Hi Anna,
What a beautiful photo of mating Small Milkweed Bugs, Lygaeus kalmii .  Large Milkweed Bugs are about 30% larger, in our observations.  See BugGuide for more information on the Small Milkweed Bug.

Letter 7 – Aggregation of Giant Milkweed Bugs

 

Subject: Is this a bee assassin?
Location: Tallahassee, FL
November 1, 2014 7:13 pm
Found a large group of these strange black/orange/yellow bugs with white spots on their backs. They are ranging in size from mickle to quarter. The large one in top right is around a quarter.
Please help.
Signature: Drew

Dear Drew,
This looks to us like an aggregation of Giant Milkweed Bugs, Sephina gundlachii, which according to BugGuide is:  “Confined to climbing milkweed, Cynanchum scoparium.”  Do you have climbing milkweed planted nearby? 

Daniel,
Thank you for the quick response! Yes, there actually is some not too far from where this picture was taken. Great info.
I have lived in FL all my life and have never seen even one Milkweed Bug, so it comes as no surprise I had to find out what was going on in this case.
Thank you for your help. I will try and make a donation to your site next paycheck. Can’t promise it will be much, but I do appreciate what you all are doing.
Regards,
Drew H.

Hi Drew,
Thanks for your kind intentions.

Letter 8 – Aggregation of Milkweed Bug Nymphs

 

milkweed bug nest
Is this a nest of adult or young milkweed bugs or do all ages swarm or nest in this fashion? This is the first time this summer that I have seen such a cluster at the conservation area. I want you to know how much I enjoy and am addicted to your website. It is fun, informative, international, and rich in content. I am more interested and curious about insects thanks to your website. Take Care,
Janet from Dundas, Ontario

Hi Janet,
First, thank you for your kind words. Secondly, these are young Milkweed Bugs. Adults have well developed wings. Many Hemipterans, and these are Hemipterans or True Bugs, form large aggregations of insecfts in all stages of development. This is nothing compared to the way Boxelder Bugs gather en masse.

Letter 9 – Blood Colored Milkweed Bug

 

milkweed bug???
January 30, 2010
I was in Tucson in October of 2009, and the Desert Milkweed was in bloom. On one occasion I got a photo of a bee on the flowers, and on another I caught this bug. In all my searching, it appears to be a Milkweed Bug, but the colors are wrong. I see descriptions of all kinds but nowhere do I see either picture or description for this coloring. Do I have the wrong identity?
Chris in Florida
Phoenix, Arizona

Hi Chris,
You are correct about this being a Milkweed Bug, but it isn’t one of the more commonly encountered species.  This is the first photo we have received in nearly ten years of a Blood Colored Milkweed Bug, Oncopeltus sanguineolentus.  According to BugGuide:  “Range  Apparent host plant is restricted to w. AZ, se. CA, and s. NV. in the U.S.  Food  Seems to have a strong affinity for Rush or Desert Milkweed – Asclepias subulata – as all photos of the bug are on that species of milkweed (so far)…  A. subulata occurs in se CA, s. NV, and w. AZ.”  Thanks so much for adding to our species archive.

Letter 10 – BUG OF THE MONTH OCTOBER 2009: Large Milkweed Bugs

 

Unidentified Milkweed Bug?
September 26, 2009
I came across these bugs while working on one of our nature preserves. I have seen the bug before but not in this context. There were several of these inside of the seed head of a couple milkweed plants. What is this bug and what is its ecological relationship with milkweed?
Derek Rogers
Nissequogue, New York

Hi Derek,
This is a group of Large Milkweed Bugs, Oncopeltus fasciatus.  The winged individuals are the adults and the others are immature nymphs.  The food plants are plants in the Milkweed and Dogbane families.  The insects feed on the juices of the seeds of the plants and will not harm the plants, and adults also take nectar.  According to BugGuide:  “In the course of feeding these bugs accumulate toxins from the milkweed, which can potentially sicken any predators foolish enough to ignore the bright colors which warn of their toxicity.”  We found a nice Milkweed Bug Information page posted by the University of Arizona that has useful information.  This is the third letter with an identification request for the Large Milkweed Bug that we have opened today.  Your photo is quite beautiful and we are selecting your letter and photo as the Bug of the Month for October 2009.  Throughout the month of October, it will remain at the top of our homepage.

Hi Daniel,
I would be honored to have my photo posted for the October bug of the month. Thank you for this information and your quick response. I am very impressed with the web site. I do nature preserve management for The Nature Conservancy and often come across interesting insect specimens. I will surely be in touch.
Derek Rogers

Letter 11 – Countdown 14 more postings to the 20,000 mark: Mating Small Milkweed Bugs

 

Subject: Little black and orange bugs
Location: Mojave, California
March 26, 2015 12:47 pm
I work in Mojave, CA and a bunch of these little guys live right outside my workplace. The thorax is a blackish/grey color while the abdomen is bright orange with symmetrical black spots. The wing coverings are orange with black shapes and two little white dots. They have six legs, two antenna, and are about the length of a thumbnail. They’re always out and about during the day, and most of them appear to be mating at this time. I tried looking them up online but couldn’t find anything so hopefully you can help me out!
Signature: Lexi

Dear Lexi,
These are mating Small Milkweed Bugs, Lygaeus kalmii, and they are generally found in conjunction with milkweed, though they may feed on other plants as well.  You can read more about Small Milkweed Bugs on BugGuide.

Letter 12 – Giant Milkweed Bug

 

Is this an assasin bug?
December 28, 2009
Hi, I love your site. While visiting a relative in Naples, Florida, I photographed this bug near a beach. I think it’s an assasin bug, but I can’t find a matching image. It flew away when I got close. Any ideas?
Sammy
Southern Florida

Hi Sammy,
Though it resembles an Assassin Bug, this is actually a Leaf Footed Bug in the family Coreidae known as the Giant Milkweed Bug, Sephina gundlachi.  According to BugGuide, it is found in Florida, and has not been reported from other states.

Letter 13 – Immature Giant Milkweed Bug from Florida

 

Subject: Red-Orange Bug Needs a Name
Location: Boca Raton, Florida
June 23, 2016 1:13 pm
Hello What’s That Bug!
Found a bunch of these little guys covering a tree at Yamato Scrub Natural Area in Boca Raton, Florida. The picture doesn’t do the bug justice – they are bright reddish-orange – really stand out in the woods! I’m not sure if this is a juvenile form or an adult form. I’m hoping you can give me a proper identification. As always, I enjoy your web site and appreciate the service you provide to us amateur naturalists!
Signature: Ann Mathews

Dear Ann,
This is an immature True Bug, and nymphs can often be very difficult to properly identify.  Most guide books only contain images of adult insects.  This Leaf Footed Bug in the family Coreidae is Sephina gundlachii, also known as the Giant Milkweed Bug (not to be confused with the Large Milkweed Bug or the Small Milkweed Bug) and we identified it thanks to this image on BugGuide.  According to BugGuide, it feeds on climbing milkweed.  Only reported from Florida on BugGuide, this is only the second report we have received.  Perhaps you will be able to send us a nice image of a winged adult in the future.

Once again, What’s That Bug comes to the rescue and identifies an unknown creepy crawly for me. I’ll do my best to get a picture of an adult giant milkweed bug. If any of the photos look halfway decent I’ll be sure to send them your way. I always learn such interesting things every time I visit your web site. I can’t say that for too many web sites these days – so keep up the great work!
Ann Mathews
Palm Beach County
Department of Environmental Resources Management

Letter 14 – Immature Large Milkweed Bug

 

Subject:  Small multicolored bug on milkweed plant?
Geographic location of the bug:  South FL
Date: 09/06/2021
Time: 09:33 PM EDT
Your letter to the bugman :  Hi there! I need help ID-ing a bug I found on a potted tropical milkweed plant I recently bought. It is a small bug ~5mm in length. Picture attached. I’ve never seen anything like this before so I was just curious as to what it was (google wasn’t much help unfortunately!).
Thank you!
How you want your letter signed:  B. Sanders

Dear B. Sanders,
Many folks purchase milkweed to attract Monarch butterflies, but they do not realize that milkweed is visited my numerous other insects.  This is an immature Large Milkweed Bug.  Here is a BugGuide image for reference.

Letter 15 – Immature Large Milkweed Bug part of experiment

 

Red and Black bug
March 7, 2010
I am doing these bugs as an experiment and I am having difficulty identifying them. They are being raised in a petri dish and eat water and sunflower seeds.
Cassalyn Sands
North Carolina

Hi Cassalyn,
You didn’t really indicate the nature of your experiment, and if sunflower seeds are a necessary component.  This is an immature Large Milkweed Bug, Oncopeltus fasciatus, and milkweed, not sunflower, is its food of choice.  According to BugGuide:  They eat the “Seeds of milkweed plants.“

Letter 16 – Immature Large Milkweed Bugs

 

Plump Black and orange bugs
I found several of these bugs in a flower garden. It was the 4th week of September around 4pm. Can you tell me what they are? If they are beneficial, I don’t want to destroy them.
Cathy M
Kennett Square, PA

Hi Cathy,
These are immature nymphs of the Large Milkweed Bug, which we just identified for you.  Like other Hemipterans, they have sucking mouthparts, and they feed on juices from the seeds and seed pods of milkweed and dogbane.  We have never located any information that this is a problematic species in the garden.

Letter 17 – Immature Large Milkweed Bugs

 

Subject:  Friend or Foe?
Geographic location of the bug:  Southern California Foothills
Date: 10/23/2019
Time: 12:50 PM EDT
Your letter to the bugman:  Hopefully this is an easy one. I am asking you to help identify these little guys. I do not want to miss identity a bug who is helping our cherry tomato plant. These showed up after the plant was established for several months.
Thank you for your time!
How you want your letter signed:  New guy

Dear New guy,
These sure look to us like immature Large Milkweed Bugs and we do not believe they will harm your tomato plants.  Here is a BugGuide image for comparison.  Is there any milkweed growing nearby?  They are also sometimes found in association with oleander.

Letter 18 – Large Milkweed Bug

 

Milkweed bug?
I came across this convention of strikingly marked bugs inside a newly burst milkweed pod – near Austin, TX on 8/7/2004. Is this a species of Milkweed Bug? What is their attraction to the plant?
Regards,
Ed Sparks

Hi Ed,
You have a great photo of Large Milkweed Bugs, Oncopeltus fasciatus. It is one of the best photos we have ever received since it shows a group on the food plant. You should consider submitting it to the Kaufman Focus Guide to Insects of North America. As true bugs, they use the sucking mouthparts to extract nourishment from maturing and mature seeds of milkweed. Sometimes adults sip nectar from the flowers of other plants.

Letter 19 – Large Milkweed Bug

 

We later spotted these Large Milkweed Bugs, Oncopeltus fasciatus, on their host plant. There were only two, and one was more colorful and cooperative, posing for these photos. They are members of the Family Lygaeidae which includes Chinch Bugs. These beautiful bugs do not damage cultivated plants, but they occasionally aggregate and hibernate in great numbers like Box Elder Bugs.

Letter 20 – Large Milkweed Bug

 

Milkweed Beetles?
Hello, Bug People!
I observed these little guys last summer in VA over the course of several weeks, from larva to adulthood, yet I’m still not sure what they are! There were a few colonies on different milkweed plants, so I figured they were milkweed beetles, but they do not look like any pictures of milkweed bugs I’ve seen. Did I misidentify my little bug friends?
Val

Hi Val,
You Large Milkweed Bugs, Oncopeltus fasciatus, are True Bugs or Hemipterans, not Beetles. They suck juices from the maturing and mature seeds of milkweed.

Letter 21 – Large Milkweed Bug

 

what bug is this
We saw this bug in our back yard. A friend said it was a soldier beetle but none of the pictures online look like this striking fellow. Many thanks for your help.
Dan Vera
Washington, DC

Hi Dan,
Unless you don’t read your email, you already know this answer. Someone sent us a similar photo with a similar camera marker and began a letter along the lines of “My friend found …” That indicates that you emailed your find to at least one person who found us before you. We responded that this is a Large Milkweed Bug. The internet is a wonderful tool, but it can get annoying when one consideres the speed with which things can travel around the world. Last month, about every third letter we opened came from some poor sad web surfer wanting the identity of a caterpillar in a video posted on a website, which was later posted on other websites and blogs, and soon our mailbox was clogged with requests. This is the modern equivalent of the hideousness of the chain letter. We wore out our delete key.

Letter 22 – Large Milkweed Bug

 

What’s this black and red bug?
I’ve found a few of these on my milkweed plant. They showed up after the aphids took over. Perhaps this black-and-red bug is an aphid killer (hopefully)?
Bonnie

Hi Bonnie,
Large Milkweed Bugs are not predators. They feed on the seeds of the milkweed. They will not harm the plant, but will reduce the number of viable seeds produced.

Letter 23 – Large Milkweed Bug

 

Unbelieveable!
I found several of this beetle in my back yard on an Oleander bush (West Central Florida). I’ve looked through thousands of pictures on the internet and haven’t found a single image of it. I clicked on your website and there it was on the cover of Eric Eaton’s new book! I think it’s some kind of leaf beetle, Chrysomelidae, but what species? … Can you help us? My daughter needs it for her science project.
Susan Polito

Hi Susan,
This is not a beetle. It is a Large Milkweed Bug, a true bug.

Letter 24 – Large Milkweed Bug

 

beetles
hi,i found these in a vegetable garden in the florida keys.what are these beetles?thanks
theresa

Hi Theresa,
These are not beetles. They are true bugs, Large Milkweed Bugs, Oncopeltus fasciatus, to be exact.

Letter 25 – Large Milkweed Bug

 

Orange and Black Bug
July 14, 2009
I’m growing Butterfly weed for the first time and there are these orange and black bug crawling on them that look a little bit like a box elder but only orange and black. (I see it’s on the cover of Kaufman field guide to insects of North America)
Bill
Alpha, IL (North West Illinois)

Hi Bill,
The Large Milkweed Bug, Oncopeltus fasciatus, will not harm your milkweed plants.  They feed on the juices of the seeds and sometimes take nectar.

Letter 26 – Large Milkweed Bug

 

Kind of insect species
August 7, 2009
Black and orange in color
Doesn’t matter
Long Island, New York

Dear Doesn’t Matter,
No one would ever accuse you of verbosity.  This is a Large Milkweed Bug, Oncopeltus fasciatus.  Both adults and immature wingless nymphs feed the seeds of milkweed by sucking on the juices. According to BugGuide:  “Eggs are laid in milkweed seed pods or in crevices between pods. About 30 eggs are laid a day, and about 2,000 over a female’s lifespan, which lasts about a month during the summer. One or more generations per year. Adults overwinter.”

Letter 27 – Large Milkweed Bug

 

Black and gold bug
September 25, 2009
Found this bug on a milkweed seed pod in a flower garden. It was in September in late afternoon. It was slightly less than an inch long. Black and gold on top, red and black undersides.
Cathy & Carlos M
Kennett Square, PA

Dear Cathy and Carlos,
These are Large Milkweed Bugs, Oncopeltus fasciatus.  The pale yellow specimen is freshly molted, and according to BugGuide:  “their color becoming darker and more orangish with age.“

Thank you so much! I’ve never seen anything like it.
I love your web site! Whenever I run into something new and interesting, you always know what it is.
Thx

Cathy Matos

Letter 28 – Large Milkweed Bug

 

orange and black bug
April 27, 2010
It is spring and we went to a park were we found this orange and black bug. There were two of them that we found on a hill. We got close to them and they did not fly off, so I believe they don’t fly.
Amanda
NE Texas

Dear Amanda,
Because they hibernate as adults, adult Large Milkweed Bugs, Oncopeltus fasciatus, like the individual in your photograph, are seen in the spring as they begin producing a new generation.

Letter 29 – Large Milkweed Bug

 

Requesting ID
Location: Brooklyn, NY
December 14, 2010 4:40 pm
Hi
Saw this critter in mid-November. Would love to know what it is.
Thanks
Signature: Barbara

Hi Barbara,
This pretty Seed Bug is a Large Milkweed Bug, Oncopeltus fasciatus.  They often form large aggregations on the pods of milkweed plants where they feed off of the juices.

Letter 30 – Large Milkweed Bug

 

Oncopeltus fasciatus?
Location: Hawthorne, CA
October 12, 2011 2:53 pm
Hi,
I believe I have this guy correctly identified as a Large Milkweed Bug. Seems as though these are common, but it’s our first sighting ever. If you remember, we did away with our back lawn last year and the drought tolerant plantings we replaced it with have attracted many ”new to us” bugs and birds. Husband Marty pointed at this flying around this morning and said, ”New bug!!” I’m glad I have him hooked. Such wonderful little buggies we have around here.
Will you please confirm?
Signature: Thanks, Anna Carreon

Hi again Anna,
This is indeed a Large Milkweed Bug.  Your gardening efforts are admirable and it is wonderful to hear that in just one year, you are attracting numerous birds and insects.  We expect that soon you will be coming out with a photo book on insects that you attracted to your newly created habitat.

Letter 31 – Large Milkweed Bug

 

Subject: Insect Project
Location: Capecod
January 12, 2014 3:39 pm
Please identify this bug for me as it is a Insect project for school.
Signature: Seana

Hi Seana,
This is a Large Milkweed Bug, Oncopeltus fasciatus.

Letter 32 – Large Milkweed Bug

 

Subject: What is this bug
Location: Southern California
July 27, 2014 3:10 pm
We see this but a lot in our garden here in San Marino California., which is right next to Pasadena, CA. We would love to know what it is. Thank you!
Signature: Mirta

Dear Mirta,
We suspect you must have milkweed in your garden.  This is a Large Milkweed Bug, Oncopeltus fasciatus, and it will feed on the seeds of milkweed, but otherwise does not harm the plant.  See BugGuide for more information on the Large Milkweed Bug.

Letter 33 – Large Milkweed Bug

 

Subject: Unknown insect
Location: Southern Ohio
April 30, 2015 7:13 pm
Greetings!
I was roving through the pasture with my Nikon and I caught this little guy. He was small and I had never seen one before. No idea what it was but it eventually unveiled its wings and flew off. I’d like to know what it was just to appease my curiosity.
Thanks!
Signature: Tyler

Hi Tyler,
Generally identification requests we receive are recent sightings, but occasionally we receive images taken in previous years.  We are curious if this is a recent sighting.  Your insect is a Large Milkweed Bug,  Oncopeltus fasciatus, and according to BugGuide, they are found:  “y[ea]r round in CA, TX, FL, otherwise mostly in late summer and fall” and “Adults overwinter.”  BugGuide further elaborates:  “They can’t survive cold winters, so they migrate south in the fall and overwinter in southern states.”  Ohio, even southern Ohio, is not considered a southern state, and though there is much talk of global warming, it is understanding that Ohio had a particularly severe winter.  We can’t help but to wonder if this individual overwintered and was observed this spring, or if it was seen in a previous year.

This was taken last year in the summer
Tyler Hickey

Thanks for the clarification.

No thank you! This is my first time using this service and I think what you guys do is wonderful and I plan to use it again. Here’s a little sketch I did of our friend.
Best,
Tyler Hickey

Dear Tyler,
We have added your beautiful sketch to the posting of your Large Milkweed Bug.

Letter 34 – Large Milkweed Bug

 

Subject: Unfamiliar True Bug
Location: Chula Vista, California
May 24, 2016 6:02 pm
Hello! First I would like to say I do love this website very much and I frequently visit it for some fun! Now on to my question; in my area there are hundreds upon hundreds of Red Shouldered Bugs running around. But just today (5/24/16), I have noticed a strange dead bug that was obviously a true bug but was not one of those very common Red Shouldered Bugs while I was walking my dog. I didn’t think about it much until I got back home and then I saw a living one in my backyard. It was about 1/2 and inch longer than an adult Red Shouldered Bug with a different pattern. I think it’s some kind of parasitic bug but what I’m hoping is that it is an assassin bug (I want to catch one so I can feed it a bunch of spiders in my house). Please identify this bug.
Signature: Stugy

Dear Stugy,
The Large Milkweed Bug, Oncopeltus fasciatus, is generally found in association with Milkweed, a plant that supports a diverse insect ecosystem.  Large Milkweed Bugs have been reported to our site in association with Oleander, a common landscape and freeway plant with toxic tendencies.  See BugGuide for species verification.

Letter 35 – Large Milkweed Bug

 

Subject:  Black & Orange Banded w/Red Head
Geographic location of the bug:  Tulsa, Ok
Date: 09/26/2017
Time: 10:34 AM EDT
I’ve seen photos of the Banded Net-Wing Beetle, but all of those have a black head. This bug has a red head. Is it different or maybe a different gender?
How you want your letter signed:  Gloria Famer

Dear Gloria,
While your critter resembles a Banded Net-Winged Beetle, it is a different species.  As a matter of fact, it is not even a beetle.  This is a Large Milkweed Bug, Oncopeltus fasciatus, a species almost always found on milkweed.  Since Large Milkweed Bugs have mouths designed to pierce and suck, not to chew, the eaten leaf can be attributed to something else.

Letter 36 – Large Milkweed Bug

 

Subject:  Red and black bug
Geographic location of the bug:  Laguna Beach CA
Date: 08/04/2018
Time: 01:25 PM EDT
Your letter to the bugman:  These bugs are constantly  on my milk weed Will they hurt the small monarch caterpillars?
How you want your letter signed:  KathyG

Dear KathyG,
This is a Large Milkweed Bug, Oncopeltus fasciatus, and it is part of the rich diversity of insects that are associated with milkweed.  Large Milkweed Bugs will not harm your Monarch Caterpillars nor will they harm the plants, but they will reduce the number of viable seeds the plant produces because according to BugGuide:  “Seeds of milkweed plants.”  Like Monarchs, they benefit from the toxins produced by milkweed plants and like Monarchs, they sport aposomatic warning colors because according to BugGuide:  “In the course of feeding these bugs accumulate toxins from the milkweed, which can potentially sicken any predators foolish enough to ignore the bright colors which warn of their toxicity.” 

Letter 37 – Large Milkweed Bug

 

Subject:  Black and orange wings
Geographic location of the bug:  Orlando FL
Date: 10/18/2018
Time: 10:44 PM EDT
Your letter to the bugman:  I was watering part of a community garden when I noticed this bright, beautiful insect. Is it a banded net-wing  beetle? Seems more fly-like.
How you want your letter signed:  Mandy

Dear Mandy,
This is a Large Milkweed Bug and here is a BugGuide image for comparison.  When milkweed is not available, Large Milkweed Bugs have been reported on oleander, another plant with a toxic milky sap.

Letter 38 – Large Milkweed Bug

 

Subject:  Milkweed Bug
Geographic location of the bug:  Central Florida
Date: 02/14/2019
Time: 12:04 PM EDT
Your letter to the bugman:  Hello Bugman!
While visiting friends in Rockledge, Florida, they showed me one of their milkweed plants that had many of these milkweed bugs on them. I haven’t, in the past, considered them to be harmful to milkweed, but would (roughly) 20 insects on one plant kill the it?
They are pesticide-free (unlike much of the rest of Florida ah-hem), so they’re either letting them be or picking them off. What advice can I give them?
Thank you!
How you want your letter signed:  Kenda

Hi Kenda,
Large Milkweed Bugs will not harm the plant.  They do feed on seeds, so large numbers of Large Milkweed Bugs might reduce seed production, but again, they do not harm the milkweed plants.

Excellent news! Thanks for all you do, Daniel, to make the planet a better place!
Cheers,
Kenda

Letter 39 – Large Milkweed Bug

 

Subject:  Winged red detailed bug
Geographic location of the bug:  Brooklyn Navy Yard
Date: 03/03/2019
Time: 09:00 AM EDT
Your letter to the bugman:  Hi- stumbled across your site and thought of this bug I saw years ago-
I believe it was at the brooklyn Navy Yard, spring or summer
Is it rare? I’ve always kind of liked insects, and have never seen anything like this
How you want your letter signed:  IcyRazer

Dear IcyRazer,
The Large Milkweed Bug is not considered rare.

Daniel-
Thanks for the quick response…
I was hoping it was some exotic bug never before seen in NY,  but great to know about the Large Milkweed Bug… it was quite beautiful, and I don’t recall ever seeing one before.
Thanks!
Thom

Letter 40 – Large Milkweed Bug

 

Subject:  Red and black bug
Geographic location of the bug:  Fountain valley, ca
Date: 03/23/2019
Time: 03:32 PM EDT
Your letter to the bugman:  Hello, Bugman!
I found three of these today on a milkweed (which I planted to attract monarchs). Two of them were mating. I live in Orange County, California, about five miles from the coast.  Any idea what it is?
How you want your letter signed:  Jennifer

Dear Jennifer,
This is a benign Large Milkweed Bug and it will not harm your milkweed plants.  According to BugGuide, they eat:  “Seeds of milkweed plants. They can be reared and fed other seeds such as sunflower, watermelon, cashew”

Letter 41 – Large Milkweed Bug adult and nymphs

 

Subject:  large milkweed bugs
Geographic location of the bug:  San Diego co
Date: 01/30/2018
Time: 06:06 PM EDT
Your letter to the bugman:  Hi,
I need help.  I have a plant that I did not know what it was.  Have decided to cut it down but when I was, I found this red and black bug on it.  I looked it up.  It is a large milkweed bug.  I figured this must be a milkweed plant.  The bees love the flowers and it has large smooth skinned pods.  The bugs love it.  I found them very interesting and have been watching them for about a month.  I may have made a mistake.  They seem to bread excessively.  It was fun to watch 30 or 50 little tiny things grow bigger but now I think there are many more than that.  They seem to still want to bread and the little things are all over the plant.  Am I in trouble?  What should I do?  Thanks for your advise.
How you want your letter signed —
Susan Rykowski

Hi Susan,
We are pretty certain the plant in question is a Bladder Flower, Araujia sericifera, which is native to South America and is featured on the Weeds of Australia website.  We faced a similar quandary with this plant several years ago when it sprouted on the fence at the What’s That Bug? offices.  We removed it after it bloomed and produced large pods.  The plant has a milky sap, which is the reason it has attracted the Large Milkweed Bugs.  Large Milkweed Bugs are native and they will not harm other plants in your yard.  They do not damage milkweed, but since they feed on seeds, they will reduce the number of viable seeds produced by a plant.  We do not provide extermination advice.  If you remove the bladder flower, an invasive species, you will also remove the food source for the Large Milkweed Bugs, though if there is oleander nearby, they will also feed on oleander.

Thanks, I did not know how dangerous it would be to have the insects in the yard in those quantities.  I am going to take the plant down after they all break open so the guys can eat the seeds.  Then limit its size and location.  It takes over unless you watch it, which I did not.  No one is going to believe you answered me and actually knew what it was.  We have been having a hard time trying to find out what it was.  I have been told you could eat the pods and you could not.  I am not!  Thanks for all your advise!  Really helpful.
Susan

I have been very very interested in the large milkweed bugs.  This is so weird for me because I have always been afraid of bugs.  I am sending this picture because I think it so strange.  I have been watching them in the evening getting on top of each other.  They pull the younger ones underneath.  In the morning when the sun hits them the ones on top start to wake up and then they start waking each of the ones underneath.  Like they are checking them.  Do you know if what I am saying is true?  Thanks  Susan

Hi again Susan,
Thanks for the update on your Large Milkweed Bugs.  There are some Heteropterans, the order to which the Large Milkweed Bug belongs, that practice parental care, including some Stink Bugs like the one pictured on Alamy and some Treehoppers like those pictured in the Bug of the Week posting of the University of Maryland.  We have not heard of this behavior in Large Milkweed Bugs, and the newest images you provided only depict immature individuals.  This is more likely a situation where forming aggregations of individuals is mutually beneficial and it is not an example of caring for younger individuals.

Update:  March 1, 2018
Hi Daniel
Hope you are not angry that I am contacting you again.  Why are some of the larger bugs turning white.  See the picture.  I don’t know if it is a young bug getting mature or a mature bug getting older.
Susan Rykowski

No Problem Susan.  The light individual is newly metamorphosed, and once the exoskeleton fully hardens, the color will darken.

Letter 42 – Large Milkweed Bug Nymph

 

Here is one for you!
I live in Tehachapi, CA and found a ton of these on the weeds next to an evergreen. Can you help?
Thanks,
Brian

Hi Brian,
This is the nymph or immature stage of the Large Milkweed Bug, Oncopeltus fasciatus. Even though they appear in great numbers, they sip nectar from gardens and crop fields but do no significant damage.

Hello again, I thought since I had the chance, I would send you a photo I took of the group of milkweed bugs. Thanks again for your quick reply. Regards, Brian

Letter 43 – Large Milkweed Bug Nymph

 

Boxelder nymph?
Location: Hidalgo County, TX
March 31, 2011 5:01 pm
Found this guy and some others which were much smaller than it running across my backyard garden.
Photo taken 3/30/2011 at 6:21pm.
Searching around, the closest I can tell is that it might be a Boxelder bug, but the markings on the abdomen are a bit different. As it is not a fully mature adult, I’m not sure what it is, hence the supposition of it being a Boxelder Nymph.
Signature: Kevin Ramsey

Hi Kevin,
Many immature True Bugs are difficult to distinguish from one another, but we agree that this is not a Boxelder Bug Nymph.  We believe it is the nymph of a Large Milkweed Bug, Oncopeltus fasciatus.  You can compare you image to this image on BugGuide.

Letter 44 – Large Milkweed Bug Nymphs

 

Good or Evil??????
Hi — I assume these are milkweed bugs that are on my milkweeds in my butterfly garden. Should I hose these guys off when I do my daily de-aphid-ing with a strong spray of the hose? I often see these guys on the milkweed plants, but I’m not sure if they do any damage. Do they eat the leaves?
Susan S. Rockwell
Alva, FL (SW Florida)

Hi Susan,
Good and Evil are such absolutes and we don’t really like talking in terms of mutually exclusive binaries when discussing insects. We would favor good over evil. Your bugs are immature Large Milkweed Bugs. Large Milkweed Bugs, Oncopeltus fasciatus, feed on the juices from the pods of the plant, and will not have a detrimental effect on the plant health.

Letter 45 – Large Milkweed Bug Nymphs

 

A type of beetle?
Location:  Ludington, Michigan
September 5, 2010 10:13 pm
Saw a group of these on milkweed. But, not prolific spotting only one plant with the bug.
Signature:  John

Hi John,
These are not beetles, but rather Seed Bugs, more specifically, the immature nymphs of the Large Milkweed Bug, Oncopeltus fasciatus.

Letter 46 – Large Milkweed Bug Nymphs

 

Young Ladybugs or Something Harmful
Location: West Los Angeles
November 12, 2011 12:30 pm
Hi Bugman,
I’ve seen a couple groups of these small red bug on my milkweed bushes.
Are they Ladybugs or something else?
Thx, Jeff Bremer
Signature: Jeff Bremer

Hi Jeff,
These are the early instar nymphs of Large Milkweed Bugs.  They feed upon the juices of the milkweed seeds and pods.  They will not cause damage to the plant, but the number of viable seeds that are produced by the plant might be reduced.  This does not appear to be a native milkweed, so the lack of seed production is not something that should be considered a problem.  We would urge you to allow the Large Milkweed Bugs to share the plants with the butterflies you are trying to attract.  You can see BugGuide for a matching photo.

Letter 47 – Large Milkweed Bug Nymphs

 

florida reddish orange black spotted insect
Location: Fleming Island, FL
November 28, 2011 5:59 pm
Hello, this afternoon i discovered these bugs on my window screen in my back garden. I’ve lived in Florida for 26 years and I am an avid gardener, yet i have never seen a bug like this before. I’m located North Florida, just south of Jacksonville. Hoping your expertise can clue me in, thanks so much for your time!
Signature: Fiona

Hi Fiona,
These are Large Milkweed Bug nymphs, and as their name indicates, they feed on the sap of milkweed pods and seeds.  If you are an avid gardener, and you like to attract butterflies, you are probably growing their food source, milkweed, however we have also gotten at least one report of them feeding on oleander, a common Florida shrub.  Here is a photo from BugGuide that matches your grouping’s stage of development.  They are not considered a harmful species in the garden.

Thanks so much for the quick response.  I have butterflyweed in the garden, not far from where I saw the bugs.  I have never noticed them before and have had butterflyweed for years, good to know what they are and that they are not harmful.  Now I can appreciate them for what they are – pretty red bugs!
Thanks again, Fiona

 

Letter 48 – Large Milkweed Bug Nymphs

 

Subject: Fat orange juvenile(?) insect.
Location: Walnut Creek CA open space near pond.
February 29, 2016 7:06 pm
I found the group of orange insects with black spots near water last August, in the Walnut Creek Open Space, California. Later I found an earlier picture of a what must be a close relative of this bug in my files. I don’t know where I found it. That one does not have the spots.
I hope you can tell me what these critters are.
Signature: Dirk Muehlner

Dear Dirk,
We wish you had not cropped your image.  These sure look like Large Milkweed Bug nymphs, Oncopeltus fasciatus, based on this BugGuide image, and they do appear to be feeding on milkweed pods, but we would love to see more of the plant to try to identify the species of milkweed.  The image you captured earlier is also a True Bug in the suborder Heteroptera, but from there the taxonomies diverge.  The Large Milkweed Bugs are Seed Bugs in the family Lygaeidae and the other is a solitary Western Boxelder Bug nymph, Boisea rubrolineata, in the Scentless Plant Bug family Rhopalidae which you can verify on BugGuide. 

Update:  March 7, 2016
Hi Daniel
Thank you for identifying these Large Milkweed Bug larvae!  You regretted that my image was cropped and I found a less cropped version, for what it’s worth.

Thanks again.   I really appreciate your response to my query.
Dirk

Wow Dirk,
We are so excited to get an image that includes the narrow leaf milkweed seed pods and the leaf is also visible.  Las Pilitas Nursery has more wonderful information on the California Narrow Leaf Milkweed, a critical plant in a vibrant ecosystem that we profile in Milkweed Meadow.

 

Letter 49 – Large Milkweed Bug Nymphs

 

Subject: Want to know if these bugs are harmful or harmless
Location: Central Florida ~ Ormond Beach
March 11, 2017 1:46 pm
These bugs appear to be eating aphids on a particular plant. Should I leave them alone or wash them off the plant. The plant is just something that grew in my garden ~ not particularly important. Current season ~ March 11
Signature: barbara malkus

Dear Barbara,
These appear to the the nymphs of Large Milkweed Bugs, Oncopeltus fasciatus, a species normally found on milkweed, but sometimes found on oleander.  We are surmising that milkweed, which is the food plant for the Monarch Butterfly, sprouted in your garden.  Large Milkweed Bugs normally feed on seeds, but if they are eating Aphids, that is a good thing.  In our opinion, you should leave them be.

Letter 50 – Large Milkweed Bug Nymphs

 

Subject:  Red and black bug
Geographic location of the bug:  Alexandria, VA
Date: 08/08/2019
Time: 12:20 PM EDT
Your letter to the bugman:  Hi, these guys have recently showed up.  They are black and red, and are all over my Milkweed
How you want your letter signed:  Nicole

Dear Nicole,
Many people plant milkweed because of Monarch Butterflies, but there are a host of insects that depend upon milkweed for survival, including these Large Milkweed Bug nymphs, Oncopeltus fasciatus.  According to iNaturalist:  “Juvenile O. fasciatus require the seed of milkweed plants for development and growth. Adults can survive on other types of seeds such as: sunflower, watermelon, almond and cashew, as shown in lab populations. Nymphs live in large groups of about 20 individuals on the plant.”  Since they feed on the seeds and not on the plants, they will not damage the milkweed and there will be plenty of leaves for Monarch caterpillars to feed upon.

Letter 51 – Large Milkweed Bug prepares for flight

 

Subject: What is this bug? a beetle? some kind of wasp moth?
Location: Debary FLorida
September 30, 2013 5:51 pm
HI! I am going nuts trying to find what that bug is…I took a picture of at the Gemini Springs park in Debary Florida.
Signature: Bugging

This is a magnificent photo of a Large Milkweed Bug, Oncopeltus fasciatus, preparing for flight.  When resting, the wings cover the abdomen.  Large Milkweed Bugs are True Bugs in the Seed Bug family.  We did find a photo on BugGuide that is similar, but not as nice as your photo.

Thank you kindly for finding about this bug and for the compliment about the photo. I love nature and I may have to pick your brain again soon!
Eric

Letter 52 – Large Milkweed Bugs

 

Hi,
We have these orange and black bugs all in our oleander bushes. Do you have any idea what they are, and if they are harmful to the plant?
Thanks,
Kathy W.

Hi Kathy,
You have Large Milkweed Bugs, Oncopeltus fasciatus. According to our literature, though they get very plentiful, they do not harm garden plants nor crops, but drink nectar from both.

Letter 53 – Large Milkweed Bugs

 

Possible to identify these beetles?
Hello, these orange and black bugs were found on a plant near a lake in Pennsylvania. Can you identify them? Thank you.
Dahlia

Hi Dahlia,
What a nice photo of the Large Milkweed Bug, Oncopeltus fasciatus.

Letter 54 – Large Milkweed Bugs

 

Zelus longipes
Hi There WTB,
You guys are awesome. Thanks for being there. I found the bug I’ve been wondering about on your site. It turns out that the Milkweed Assasin bug(photo attached) has probably been what’s almost completely zeroed out the Monarch population in our garden. They are covering one particular Butterfly Weed bush in the hundreds. Knowing they bite now, I am concerned to leave them there. We have a 16 month old curious little boy and no more Monarchs. What can I do…relocate them? And will you answer me back to my e-mail address or should I keep checking your site for an answer? Thank you so much,
Heather Green – Los Angeles, CA

Hi Heather,
You are mistaken. Your bugs are Large Milkweed Bugs. They are in the same order as Assassin Bugs, Hemiptera, but they are non biting Seed Bugs in the family Lygaeidae. Large Milkweed Bugs, Oncopeltus fasciatus, feed on the juices of seeds of Milkweed and some other plants, reducing the number of viable seeds, but otherwise not doing significant damage to the plant. We respond personally as well as posting letters to our site, but we are never able to answer all of our mail. Sadly, this enrages some people who write to us.

Letter 55 – Large Milkweed Bugs

 

Congregation of the Milkweed Bugs
Location:  Swanton, OH
August 29, 2010 12:40 pm
I’m sure this is a pretty normal sight this time of year, but I was still pretty exciting to find this many buggers in one place!
Katy

Hi Katy,
Thanks for sending us your photo of Large Milkweed Bugs, Oncopeltus fasciatus.  Because they are a relatively common sight at this time of year is a perfect reason to post your photograph.

Letter 56 – Large Milkweed Bugs

 

Subject: Hi Daniel – Large Milkweed Bug
Location: Hawthorne, California
August 6, 2012 7:45 pm
I know you have plenty of these wonderful bugs posted, but don’t see any of the newly emerged Large Milkweeed Bug. Marty pointed one out to me the other day, and I got the best shot I could. They seem to be very shy at this stage and scoot underneath the milkweed leaves every time they see me. Thought I would send these photos your way. We’re on the lookout for more and hope to get better photos.
Signature: Anna Carreon

Hi Anna,
Thanks for keeping us abreast of the latest insect visitors in your garden.  This newly metamorphosed Large Milkweed Bug will soon darken to the typical black and orange coloration visible in your other photograph.

 

Letter 57 – Large Milkweed Bugs

 

Subject: Milkweed bug
Location: Richmond, VA
March 24, 2016 1:28 am
Hello bug man!
I would like to know if these bugs are milkweed bugs or kissing bugs or neither! I spend a lot of time in my garden and saw these guys hanging out. Want to make sure they can’t seriously harm me. Thanks so much for your help.
Signature: Nai ford

Dear Nai,
Your image depicts a group of Large Milkweed Bugs, Oncopeltus fasciatus, both winged adults and wingless nymphs.  They are harmless.

Awesome!! Thanx for responding so quickly. Very kind of u. Take care.

Letter 58 – Large Milkweed Bugs

 

Subject: Garden bug swarms
Location: Sioux Falls SD 57106
October 2, 2016 3:43 pm
My moms curios whats happening in her city flower garden. Sioux falls, SD. Late sept to early oct. On butterfly plants only that are seeding. One plant has larger bugs not afraid of humans. Those are easy to photograph she said. Another plant 8 feet away has small bugs very skitterish hard to get close photo. This plant also has 1 large boxelder looking bug babysitting i think.
Signature: Michael J Theesfeld

Dear Michael,
All the images you submitted depict Large Milkweed Bug nymphs in various stages of development, however, there are no fully winged adult Large Milkweed Bugs, Oncopeltus fasciatus, evident in the images.  According to BugGuide both nymphs and adults feed on  “Seeds of milkweed plants” and “In the course of feeding these bugs accumulate toxins from the milkweed, which can potentially sicken any predators foolish enough to ignore the bright colors which warn of their toxicity.”

Thank you for the prompt and informative reply its much appreciated.  God Bless.

Letter 59 – Large Milkweed Bugs

 

Subject: Red bugs in WLA
Location: WLA,: University High School
January 16, 2017 11:43 pm
We found these bugs congregating on a vine near University High School in WLA today. They like the pod like fruit of the vine. There seem to be various stages of development of this bug all living together. Could not see any damage to the vine or fruit/pod of the vine though.
Signature: Margee & Des

Dear Margee & Des,
The insects are various stages of immature nymphs and a single, winged adult Large Milkweed Bug, and finding them on the vine indicates it is either a member of the milkweed family or that it has sticky white sap.  Large Milkweed Bugs are sometimes found on oleander.  They are generally found on the seed pods of milkweed, and they do not do significant harm to the plants, but may effect the number of viable seeds produced.

Thank you so very much for your quick response. We had never seen this bug before and were really curious. Appreciate your effort! ? ?

Letter 60 – Large Milkweed Bugs

 

Subject:  insects on milkweed plants
Geographic location of the bug:  Manhattan Beach, CA
Date: 11/05/2017
Time: 12:36 PM EDT
What is it?   Have never seen it before in 20 years at this location.   Is it beneficial or a bit of a problem? These plants also get hit by yellow aphids – I am hoping these red and black beauties eat aphids
How you want your letter signed:  Sue Randolph

Dear Sue,
These are Large Milkweed Bugs, and they will not harm your milkweed plants, but they do feed on the seeds and seed pods, which does not harm the plant, but will reduce the number of viable seeds for next year.  Like many insects that feed on milkweed, Large Milkweed Bugs have aposomatic or warning coloration.  Large Milkweed Bugs are also reported to feed on oleander.  Many True Bugs that feed on plants are also reported to feed on smaller insects, and we would love to fantasize that Large Milkweed Bugs might occasionally feed on Oleander Aphids.

Thank you –  I will let them enjoy themselves 🙂

Letter 61 – Large Milkweed Bugs: adults and nymphs

 

alien?
This mysterious bug was seen for three days on a cinderblock outside my shop at work in chaddsford,pa.,late summer/early fall in morning when I arrived.It would disappear thru out day,but be there in morning,on the fourth day,it appeared to be just a outershell as if it moulted or had been eaten.I’m also including a pic. of I think"milkpod bugs"?,taken in ocean city,maryland.You can zoom in on pic to get more detail,I just don’t know how to edit&save pics yet,Thanks for any light ya can shed on mystery bug,sorry for crappy photos,I’m a novice w/digital cams. Have a nice day,
Tom

follow up alien?
Hello again gentleman,
I’m Tom,who sent recent mail w/pics of bug in chaddsford,which was approx 1.5″inlength, &milkpod?bugs in oceancity,maryland. I’ve been checking your site since,I think chaddsford bug may be in family of assassin bugs?lncluding those in maryland?.I look forward to a possible reply in future. Your site is addictive and has been added to my favs.tab.Thank you once again for your time,
Tom from glenolden,pa

Hi Tom,
Your “alien bug” is an Assassin Bug, but the photo isn’t clear enough to be certain of the species. Our best guess is Reduvius personatus, the Masked Hunter. Your photo of the adult and immature Large Milkweed Bugs, Oncopeltus fasciatus, is quite nice and we are happy to post it in order to assist our readership in future identifications.

Letter 62 – Large Milkweed Bugs Mating

 

Bug Love, Milkweed Bugs
Hi-
Thought you might appreciate these two snapshots of milkweed buglove (50 miles north of Chicago, in extreme northeastern Illinois). I know you have already posted two affectionate milkweed bugs but thought you’d enjoy the little “wing thing” one of them did in the middle of it all!
Lorraine Bunn
Fox Lake, IL

Hi Lorraine,
Your photo has surely captured the heat of bug passion between two Large Milkweed Bugs with the wing action a nice gesture of abandon. Nice touch that they are on a milkweed pod.

Letter 63 – Mating Small Milkweed Bugs

 

Subject: Bright orange bug
Location: Tempe, Arizona
October 10, 2015 5:01 pm
So this outside near the pool
Signature: Alison

Dear Alison,
These are mating Small Milkweed Bugs, Lygaeus kalmii, a species that will not do any harm to your garden, though they may reduce the number of milkweed plants that sprout from seeds.  According to BugGuide citing The Life of a Californian Population of the Facultative Milkweed Bug Lygaeus kalmii:  “Adults suck nectar from flowers of various herbaceous plants, and also feed on milkweed seeds(?). Also reported to be scavengers and predators, especially in spring when milkweed seeds are scarce. They have been reported feeding on honey bees, monarch caterpillars and pupae, and dogbane beetles, among others.”

Letter 64 – Mating Small Milkweed Bugs

 

Subject: Black and Orange bugs that seem to attach together at back end
Location: Henderson, NV
June 15, 2016 8:53 am
Hi! I’m a new homeowner and found these bugs recently. They are normally single, but they will occasionally come together at their backside and even move in unison when I approach them. Do you know what I’m dealing with here? Thanks!
Signature: New Homeowner

Dear New Homeowner,
These are mating Small Milkweed Bugs, and they pose no threat to your new home.

Letter 65 – Mating Small Milkweed Bugs

 

Subject:  What is the Scientific name of this bug
Geographic location of the bug:  Hemet California
Date: 08/28/2018
Time: 10:17 AM EDT
Your letter to the bugman:  Can you help me identify the bug in the accompanying picture
How you want your letter signed:  doesn’ matter

These are mating Small Milkweed Bugs, Lygaeus kalmii.  They are a benign species that does not harm plants in the garden.

Letter 66 – Mating Small Milkweed Bugs

 

Subject:  What’s this Bug?
Geographic location of the bug:  Mesa, AZ
Date: 09/09/2021
Time: 07:17 PM EDT
Your letter to the bugman:  What’s this bug?
How you want your letter signed:  J Craghead

Dear J Craghead,
These are mating Small Milkweed Bugs and they are no cause for concern.  You can read more about Small Milkweed Bugs on Bug Eric.

Letter 67 – Maybe French Milkweed Bugs

 

Would you identify these bugs? I live in S.W.France. Are they harmful to the lime tree that they have infested? if so, how do I get rid of them? Many thanks for your help.
Michael Warrack

Hi Michael,
I am not as familiar with French insects, but it appears you have an aggregation of Seed Bugs, Family Lygaeidae, of some sort, possibly a type of French Milkweed Bug. Seed Bugs are True Bugs and most suck juices from developing or dry seeds or the sap of grasses. They are known to form aggregations, sometimes to hibernate. My best guess is that they are not harming your lime tree, but using it as a gathering site.

Letter 68 – Milkweed Bug Aggregations: Multigenerational Family

 

Milkweed bug life cycle
Location:  Kitchener Ontario Canada
October 8, 2010 12:44 pm
Hi, I saw someone submit a photo of these guys missing the adult and smaller phases.
So giving you one with more life stages.
Signature:  Martzart – Don Martz

Dear Martzart,
We hope you aren’t too upset that we took your gorgeous piece of art and cropped it and flopped it so that it would better fit our format.  Most of the nymphs in your photograph are coevals, but we are not certain if it is the third or fourth instar.  The tiny nymph and the winged adult in the lower right corner make your image a wonderful documentation of a multigenerational aggregation.

Letter 69 – Milkweed Bug Nymphs

 

Subject:  Would love to is this bug
Geographic location of the bug:  Eastern panhandle of WV
Date: 10/22/2017
Time: 11:06 AM EDT
This bug is in a large grouping in my raised bed which not has leaf litter and many dying zinnias. There is also parsley in the area.
How you want your letter signed:  Sandra

Dear Sandra,
These are immature Seed Bugs in the family Lygaeidae, and immature individuals can be difficult to identify conclusively.  Was there any milkweed near where they were found?  These look like Milkweed Bug nymphs to us, but we cannot state for certain if they are Small Milkweed Bug nymphs, Lygaeus kalmii, which are pictured on BugGuide, or Large Milkweed Bug nymphs, Oncopeltus fasciatus, which are also pictured on BugGuide.

Letter 70 – Mutilated Large Milkweed Bug

 

Subject: What is it?
Location: Berwyn, Illinois
October 6, 2014 12:49 pm
Hi! This fellow was sitting on a leaf in suburban Chicago today.
Signature: Debbie Mercer

Dear Debbie,
This looks to us like a Large Milkweed Bug, but for some reason, its beautiful, aposomatic wings have been ripped off.  We cannot imagine what could have done this.  It does not seem like a natural accident, nor does it seem like predation thwarted.

Letter 71 – Newly Metamorphosed Large Milkweed Bug

 

Subject:  large milkweed bugs
Geographic location of the bug:  San Diego co
Update:  March 1, 2018
Hi Daniel
Hope you are not angry that I am contacting you again.  Why are some of the larger bugs turning white.  See the picture.  I don’t know if it is a young bug getting mature or a mature bug getting older.
Susan Rykowski

No Problem Susan.  The light individual is newly metamorphosed, and once the exoskeleton fully hardens, the color will darken.

Thank you.  I really am afraid of bugs.  this is a whole new experience for me.
Thanks for helping me.
Susan

Letter 72 – Possibly Large Milkweed Bug Nymphs

 

Subject: Identify beetle
Location: lat: 34.328092 long: -118.451715
May 5, 2013 12:08 pm
Bugman,
Trying to ID this ”beetle” found in an area where horses are staged for trail riding. The area is surrounded by non-native ponderosa pine stand. Sylmar California, at Wilson Saddle trailhead. Thought they were Democrat Beetles, but not quite
Signature: Dean

Dear Dean,
We believe you are referring to Democrat Bugs which are True Bugs in the order Hemiptera, not beetles.  These are not Democrat Bugs, but they are Hemipteran nymphs.  We believe they might be Large Milkweed Bug Nymphs.  You can compare your individuals to this image from BugGuide.

Letter 73 – Possibly Milkweed Bugs from Costa Rica

 

Subject: beetle
Location: costa rica
March 25, 2013 12:23 pm
yellow red and green beetle
Can you help me?
Signature: fred from belgium

Dear Fred,
These are not beetles.  They are True Bugs in the suborder Heteroptera.  They remind us of North American Milkweed Bugs in the genus Oncopeltus.  We tried searching that and found a very similar though not exact photo identified as being in that genus on FlickR.

Letter 74 – Six Spotted Milkweed Bug in Baja

 

Subject:  What’s this bug
Geographic location of the bug:  Baja Sur
Date: 06/21/2021
Time: 11:47 PM EDT
Your letter to the bugman:  Hi, I’ve seen this bug a few times over the years but cannot find a photo and name for it on the web.
How you want your letter signed:  Ryan

Dear Ryan,
We quickly identified your Seed Bug as a Six Spotted Milkweed Bug, Oncopeltus sexmaculatus, thanks to images posted to BugGuide.

Letter 75 – Six Spotted Milkweed Bugs

 

Subject: Found multi color bug which I’ve never seen before
Location: South Texas
January 5, 2017 4:47 pm
Hello! Today whilst looking around my yard I saw a yellow, red/orange and black bug which I’ve never seen before around my fence and near the ground. From what I could tell they had 6 legs, 2 antenae and had weird patterns etched to their backs. The larger one had more black whilst the smaller ones were more yellow (not sure if they are the same species). They all seemed to be close together as shown in the picture.
Though it’s winter at the moment, they are very mild and usually never reach below freezing even when a cold front approaches.
-Sorry if the picture is not a close up shot, it was the best I could do.
Thanks for your time and dedication!
Signature: Agon

Dear Agon,
You high resolution image is perfectly fine for identifying these Six Spotted Milkweed Bugs, Oncopeltus sexmaculatus, a species that according to BugGuide is “Similar to Large Milkweed Bug, but with a red head, and a slightly different spot pattern.”  Based on BugGuide data, Six Spotted Milkweed Bugs are only reported from Texas within the United States, and your submission represents a new species for our site.  Your image depicts both winged adults and wingless, more yellow nymphs.

Letter 76 – Small Eastern Milkweed Bug

 

Hello! It took a few minutes of investigating but I was able identify these as milkweed bugs. It is the heart shaped pattern that made me run to get my camera! Take Care,
Janet

Hi Janet,
Thanks for sending in such a great photo of a Small Eastern Milkweed Bug, Lygaeus kalmii.