What Eats Blister Beetles: A Friendly Guide to Natural Predators

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When it comes to the natural world, the food chain plays a vital role in maintaining balance among various species. One such insect is the blister beetle, known for its ability to produce blisters upon contact with human skin. You might be wondering what creatures prey on these beetles.

Blister beetles have quite a few predators. For example, their larvae, also known as triungulins, act as effective biological control agents against grasshoppers. Their versatility in habitats and life cycles make them a target for various predators in the animal kingdom.

As you learn more about this fascinating insect, you’ll come across different species of beetles and their unique characteristics. Understanding their predators can help you appreciate the intricate balance of nature and the vital role these insects play in their ecosystem.

Understanding Blister Beetles

Blister beetles belong to the Meloidae family within the Coleoptera order. These beetles come in various colors and sizes, such as black blister beetles, brown ones, and those with stripes. You may also encounter the Lytta vesicatoria, which has a metallic green appearance. Mylabris is another type found within the Meloidae family.

Blister Beetles can be identified by their unique body shape:

  • Long, narrow body
  • Broad head
  • Straight antennae, about one-third of their total body length

These beetles are named after their ability to produce blisters upon contact with human skin. They excrete a toxin called cantharidin, which leads to this reaction. It’s essential to be cautious when handling these insects.

Blister beetles have a fascinating life cycle. They primarily feed on grasshopper eggs, which could explain their attraction to alfalfa plants and other crops. Due to their feeding habits, you might find them in arid southern states and plains states, where grasshoppers are more prevalent.

As you continue to learn about and observe blister beetles, remembering these key features will help you recognize and differentiate between the various species present in the Meloidae family. Remember to handle them with care to avoid skin irritation.

Predators of Blister Beetles

Various predators find blister beetles as a source of nourishment. Among them, you can find a range of species such as birds, reptiles, and even some insects. In this section, we’ll briefly discuss the main types of predators that are known to prey on blister beetles.

Birds

Many birds are known to eat insects, and blister beetles are no exception. Some bird species that feed on these insects include chickens, quails, and grouse. Chickens, in particular, are known to consume large numbers of blister beetles, helping control their population in the process.

Reptiles and Amphibians

Reptiles, such as lizards and snakes, may also prey on blister beetles. Lizards find these insects in their natural environment and feed on them when the opportunity arises. Toads are also known predators of blister beetles, consuming them as part of their varied diet.

  • Some examples of reptiles that prey on blister beetles:
    • Lizards
    • Snakes
  • Amphibian example:
    • Toads

Mammals and Insects

Rodents like hedgehogs could potentially eat blister beetles, though their dietary preferences may vary depending on the individual. Additionally, certain spiders may prey on these beetles, using their webs to catch them or ambushing them on the ground.

Now that you know some of the primary predators of blister beetles, it’s clear that these insects play a role at various levels of the food chain. From birds to lizards, and even spiders, many species benefit from the presence of these beetles in the ecosystem.

Life Cycle of Blister Beetles

In the life cycle of blister beetles, there are several stages to consider: eggs, larvae, pupae, and adults. They typically have one generation per year and spend the winter as larvae. Let’s briefly explore each stage in the life cycle.

Blister beetle females lay clusters of eggs in the soil during the summer. When these eggs hatch, the young are called triungulins. You can find triungulins in the fall as they immediately start searching for their food source: grasshopper eggs.

The triungulins are known for their mobility and will latch onto bee or grasshopper hosts. They continue to develop as larvae, feeding on the host’s eggs.

Springtime brings the pupal stage for blister beetles. They pupate underground, and after about two weeks, adult blister beetles emerge in early summer.

Adult blister beetles have some unique features:

  • Soft bodies
  • One-half to one inch long
  • Head is broad and vertical

The adult male and female blister beetles will feed and mate during early summer. After mating, the females will continue the life cycle by laying eggs in the soil.

In summary, the life cycle of blister beetles includes the following stages:

  • Eggs: laid in soil during summer
  • Triungulins: hatch and search for grasshopper or bee hosts
  • Larvae: feed on host eggs as they develop
  • Pupae: underground during spring
  • Adults: emerge in early summer, feed, and mate

Throughout their life cycle, blister beetles impact their environment by consuming leaves, stems, and flowers as well as preying on the eggs of other insects like bees and grasshoppers, such as Sitaris muralis. Make sure you’re aware of the blister beetle’s life cycle and its impact on other species when encountering them in nature.

Feeding Habits

Blister beetles have a diverse diet that includes a variety of plants and insects. In this section, you will learn about the feeding habits of these beetles and the types of plants and insects they consume.

Blister beetles consume plant parts like leaves and flowers, while some species even feed on soil. They are especially attracted to blossoms in plants like alfalfa, but if these are not available, they will consume leaves as an alternative. These beetles have also been observed to feed on pigweed, goldenrod, goathead, puncturevine, peanuts, soybeans, and many other plants.

In addition to plants, blister beetles also feed on insects. One example is the ebony blister beetle that consumes the eggs of the differential grasshopper. Other species may consume additional insect eggs or even tiny insects, such as aphids.

While feeding, blister beetles may also encounter pollen and nectar. First instar larvae of some blister beetle species have been found in flowers, which indicates that they might feed on these resources as well.

It’s important to remember that blister beetles can be both beneficial and harmful to your garden. Here’s a comparison table to help you understand their pros and cons:

Pros Cons
Control grasshopper populations by feeding on their eggs Can cause serious damage to plants when they feed on leaves and flowers
Help with pollination by visiting flowers Release toxic chemicals when threatened, which can be harmful to livestock and humans

By understanding the feeding habits of blister beetles, you can make informed decisions about how to manage them in your environment. Remember to be cautious when encountering these beetles, as their toxic secretions can be harmful.

Blister Beetles and Their Impact on Crops

Blister beetles can cause significant damage to various crops, especially when they gather in large clusters. Some common crops that blister beetles can affect include alfalfa, potatoes, tomatoes, eggplants, and field crops like soybeans and sweet clover.

In particular, blister beetles are notorious for their attacks on alfalfa and vegetables such as potatoes and tomatoes. These beetles tend to feed on blossoms, but they’ll go for leaves if blossoms aren’t available. Their presence in alfalfa has been a concern for hay producers as well.

When comparing the impact of blister beetles on various crops, here’s a simple table to highlight the targets:

Crop Commonly Damaged?
Alfalfa Yes
Potatoes Yes
Tomatoes Yes
Soybeans Moderate
Sweet Clover Moderate
Eggplants Moderate

Keep an eye out for these signs of blister beetle damage:

  • Defoliation of plants
  • Damage on blossoms
  • Visible large clusters of beetles

To avoid blister beetle damage to your crops, consider implementing management strategies focusing on proper monitoring and timely actions. By taking preventive measures, you can protect your crops from these potentially destructive pests.

Blister Beetles and Human Interaction

When dealing with blister beetles, it’s important to take precautions to avoid direct contact with the beetles. Wearing gloves while gardening can help protect your hands from the beetles’ toxic secretions. Some common garden plants, such as pigweed, can attract blister beetles, making it easier to locate and handpick the beetles from your garden.

Implementing a trap crop can be an effective way to manage blister beetles in your garden. By planting a preferred host plant, like pigweed, around the perimeter of your garden, you can lure the beetles away from your desired crops, thereby reducing the risk of infestation and damage.

To help you decide between handpicking and using a trap crop, consider these pros and cons:

Handpicking:

  • Pro: Immediate removal of beetles from your garden.
  • Con: Time-consuming and may expose you to toxins if not wearing gloves.

Trap crop:

  • Pro: Reduces the risk of infestation in your main garden area.
  • Con: May require additional space and maintenance.

Here are some key points about blister beetles to remember:

  • Blister beetles produce a toxic substance called cantharidin.
  • Wearing gloves while gardening helps protect your skin from the beetles’ secretions.
  • Pigweed is an effective trap crop and host plant for managing blister beetles.
  • Handpicking blister beetles requires diligence and proper protection.

Overall, by understanding and utilizing these prevention methods, you can effectively manage blister beetles in your garden and ensure a healthy and successful crop.

Managing Infestations

You may encounter blister beetles in your garden or fields, which can be a nuisance and harmful to plants. It’s essential to manage infestations effectively using safe and environment-friendly methods. Here are some options to consider:

Diatomaceous Earth: Sprinkling diatomaceous earth on affected plants can deter blister beetles by creating a rough surface that’s uncomfortable for them to walk on. This method is a natural, non-toxic option that won’t harm your plants.

Soapy Water: A simple solution of soapy water can be sprayed on infested plants to help control blister beetles. The soap suffocates the beetles and helps remove them from your garden.

Trap Crop: Planting a trap crop nearby can divert blister beetles away from your main crops. For example, goldenrod and pigweed are known to attract blister beetles and can serve as a suitable trap crop.

Spinosad: This natural insecticide can be used to manage blister beetles effectively. However, spinosad should be applied with caution as it may also affect beneficial insects.

Remember to consider the pros and cons of each method and select the most suitable option for your situation. Keep in mind that early detection and prevention are crucial for managing blister beetle infestations.

Chemical Components and Their Effects

Blister beetles contain a toxic compound called cantharidin. This chemical is primarily known for its toxicity and various effects on both animals and humans. When consumed or coming into contact with the skin, it can cause severe irritation and blistering1.

Some interesting facts about cantharidin:

  • It is used as a defensive mechanism by blister beetles2.
  • It has the potential to be lethal if ingested in high amounts3.
  • Horses are particularly susceptible to cantharidin’s toxicity4.
  • Cantharidin is also found in the infamous aphrodisiac, Spanish fly5.

Toxicity in horses can vary based on the amount of cantharidin ingested, and the symptoms can be severe. Signs of toxicity can include:

  • Excessive salivation
  • Colic, diarrhea, and gastrointestinal issues
  • Stiffness and muscle spasms
  • Rapid breathing and heart rate6.

One of the reasons blister beetles are highly toxic to horses could be due to their inability to metabolize and eliminate the chemical cantharidin from their digestive systems efficiently7.

When it comes to survival, blister beetles have developed unique ways to protect themselves. They use chemicals, such as cantharidin, to ward off predators, and their eerie ability to mimic their surroundings, also known as camouflage, to further avoid detection8.

In conclusion, the primary toxin found in blister beetles, cantharidin, has various effects on animals and humans. Understanding the chemical components and their effects can help prevent accidental consumption and facilitate better management of these fascinating, yet dangerous insects.

Environmental Adaptations

Blister beetles are quite adaptable and can be found in various environments. In North America, they inhabit a range of habitats such as ground, fields, grasslands, and forests. This adaptability allows them to thrive in different conditions.

Their unique life cycle helps them survive the winter, as their larvae are the primary overwintering stage. The presence of parasitoid wasps in their environment provides an extra challenge, but blister beetles have evolved approaches to evade these predators.

Some features of blister beetles that contribute to their adaptability include:

  • Leathery wings: These provide the beetles with better protection and mobility in various environments.
  • Shades of gray: Their coloration helps them blend into their surroundings, especially in fields and forests.
  • Wing covers: These protect the delicate wings when they are not flying and enable them to move easily in grasslands and among vegetation.

Blister beetles often reside in areas where their food sources, such as grasshopper eggs, are abundant. For example, they can be found in fields and grasslands teeming with these eggs, allowing them to fulfill their ecological role as biological control agents.

Identification of Blister Beetles

Blister beetles are distinct insects that can be identified using specific characteristics. These beetles possess a soft, elongated body with a broad head and straight antennae, which are roughly one third the length of their body. Many species are black, brown, or display drab colors, but there are some with iridescent blues or bronzes.

They can range in size from 0.5 to 1.25 inches long, and some species exhibit yellow stripes on their body. Unlike other similar-looking insects, such as false blister beetles or long-jointed beetles, blister beetles have a hard exoskeleton.

The shape of their pronotum (the area just behind its head) is narrower than their head and the rest of their body. Their wing covers are rounded, curving around their body. This makes it easy to differentiate them from other beetle families.

When you’re trying to identify blister beetles, it’s important to remember these key features:

  • Soft, elongated body shape
  • Antennae about one third their body length
  • Pronotum narrower than head and rest of body
  • Rounded, curved wing covers

By noting these distinct characteristics, you can easily identify a blister beetle while avoiding mistaking it for a similar insect.

Other Interesting Facts About Blister Beetles

Blister beetles belong to the family Meloidae and are known for their ability to produce a toxic substance called cantharidin. This substance can cause blistering on the skin and mucous membranes.

Blister Beetle Larvae: The larvae of blister beetles, particularly those in the Epicauta genus, have a unique method of finding their food. They feed on grasshopper eggs, which are often found in alfalfa produced in arid southern states and plains states where grasshoppers are more of a problem1

Meloinae Tribe: The tribe Meloinae is one of the largest within the blister beetle family and includes many well-known species. Their unique biology makes them fascinating to study.

  • Larvae undergo hypermetamorphosis, a process where they go through several dramatically different-looking stages.
  • Adult beetles in this tribe are known to secrete cantharidin as a defense mechanism.

Warts: Blister beetles are sometimes called “wart beetles” due to the warty projections on their bodies. These warts give them a distinctive appearance.

Mating: The mating process of blister beetles is quite intriguing. Males will often approach females while carrying a defensive chemical called cantharidin. They offer this to the females as a nuptial gift, which the females can use to protect their eggs2.

In summary, blister beetles are interesting creatures with unique characteristics and fascinating behaviors. Their larvae feed on grasshopper eggs, their warty appearance is distinct, and their mating process involves exchanging defensive chemical gifts.

Footnotes

  1. Blister Beetle – Texas A&M University 2

  2. Blister Beetles – Chemical Ecology Lab 2

  3. Toxicity of Blister Beetles – Pet Poison Helpline

  4. Blister Beetle Toxicosis in Horses

  5. Spanish Fly – The Chemical History of Cantharidin

  6. Symptoms of Blister Beetle Poisoning in Horses

  7. Cantharidin Toxicity in Horses

  8. Camouflage in Insects – Journal of Insect Science

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 – Lytta cyanipennis, a Blister Beetle

 

Iridescent Beetle?
Hi,
I found this beetle high up on a plateau near Rock Creek BC. I thought the iridescent greem covering the abdomen an wing casing was beautiful. However, I don’t know what kind of insect it is?
Rick Hartnell

Hi Rick,
We checked with Eric Eaton to get an actual species identification on your Blister Beetles. He quickly responded: “I’m envious. I grew up in the Pacific Northwest and never once saw these guys! These are indeed blister beetles, probably Lytta cyanipennis. Blister beetles are very LOCALLY abundant, for very short periods, so the person is lucky to have encountered them. Just don’t grab one, as they will live up to their name by leaving blisters on sensitive areas of your skin.”

Letter 2 – 2 Species of Blister Beetles

 

One for your collection and one to answer
Hi Bugman,
I was able to identify this first bug, thanks to your website, as an Iron Cross Blister Beetle. I’m stumped on the next one though. I found it scooting across the desert floor outside of Ridgecrest, California. It was about 3/4 of an inch long. Any idea?
Fred

Tegrodera latecincta Cysteodemis armatus


Hi Fred,
Both of your beetles are in the Blister Beetle Family Meloidae. First thanks for the new photo of the Iron Cross Blister Beetle, Tegrodera latecincta. The second one we located on BugGuide and it is the Spider beetle, Cysteodemis armatus. According to the site: “There is some variation in color of these beetles. Sometimes the abdomen appears to be blacker in some individuals. They are typically found in desert areas.”

Letter 3 – Thai Mystery Beetle: Blister Beetle Eletica rubripennis

 

Longhorn Beetle ?
Hi, it’s dave from Northeast Thailand again. You did such a good job identifing the Owlfly larva I thought maybe you can tell me what this is. At first I thought it was a Longhorn beetle but now I’m not so sure. It doesn’t appear to have any ocelli eyes, just the large compound ones. It’s 4-5 inches long. Thanks for any help you can give me.
Dave Sweetland

Hi Dave,
We are waiting to hear back from Eric Eaton regarding his opinion of your freaky looking beetle.

I’m attaching a front head shot so you can see what a weird looking head this guy has. Thanks again,
Dave Sweetland

Update: (12/30/2005)
Here is Eric Eaton’s conclusion: ” Ah, well, it is much better viewing the beetle image on the website. Not that it helps me ID the thing, mind you! Ha! My initial reaction is: blister beetle (family Meloidae), just going by the “Gestalt” method. The head and antennae sure suggest that, but 4-5 INCHES? I guess it is possible….Anyway, you could start with Meloidae and see where it takes you. If I get anywhere myself, I’ll let you know.” Taking Eric’s suggestion we quickly located Eletica rubripennis on this site.

Letter 4 – Spanish Blister Beetle

 

Spanish Bug
Hello;
My girlfriend and I were on vacation in Spain. While on a hike through some Olive and Almond orchards, we came across this interesting fellow. It was about 1.75 inches long. The area we were in is the mountains just north of Valencia.
Thanks!
Jeff Pitts
Austin, TX

Hi Jeff,
This is a Blister Beetle in the Family Meloidae. Side note: one beetle in this family is ground up into the aphrodesiac “Spanish Fly”.

Letter 5 – Spider Beetle: a type of Blister Beetle

 

Cysteodemis armatus
Your wonderful site has helped me id this beautiful spider beetle, Cysteodemis armatus. I’m curious if the coloring is inherent or if it’s pollen laden? I didn’t want to disturb it to find out. Thanks for the great resource!
Adriano

Hi Adriano,
Your photo is stunning. We aren’t sure about the pollen theory, so we will check with Eric Eaton to get his opinion. Though the genus seems accurate, the possibility exists this is a different species. Please write back and tell us where this photo was taken.

The photo was taken at the base of the Ship Mountains in the Mojave Desert.

Eric Eaton wrote back: ” I guess my response to the blister beetle never reached you….I agree on Cystedemus, but it is probably the “other” of the two U.S. species. I don’t have a reference that lists both names, sorry.”

Letter 6 – Romanian Blister Beetle

 

Curious about this "beast" 🙂
Hello!
I would appreciate if you could tell me what is this bug. I took the pictures next to a hill, close to the river Danube’s delta, in Romania (Europe).
Best regards,
Natalia

Hi Natalia,
This is some species species of Blister Beetle in the family Meloidae.

Letter 7 – Spanish Blister Beetle

 

Hello there,
I found this bug in the southern part of the Sierra de Gredos in Extremadura in Spain at about 600 m altitude. Do you know what it is?
Regards,
Bodo

Hi Bodo,
This is a Blister Beetle in the family Meloidae. It closely resembles an American species in the genus Megetra.

Letter 8 – Slovakian Blister Beetle

 


I live in Slovakia and i have never seen something like this bug.. it was about 5 centimeters long. What do you think about it?
Roman

Hi Roman,
Your Blister Beetle looks nearly identical to new world species in the genus Meloe, commonly called Oil Beetles.

Letter 9 – Short Winged Blister Beetle

 

Blister beetle/don’t touch!
Hi. My three year old took these pictures of this beetle today; a blister beetle? I was trying to teach him not to touch/pick up anything we find in the yard. Didn’t know if you would like to use the photos as they turned out very well for him! We love checking out the bugs on your site. Thanks,
Sharon and Caleb Katz

Hi Sharon and Caleb,
It seems Caleb might have a future as a camera person. The Short Winged Blister Beetle is also known as an Oil Beetle.

Letter 10 – Blister Beetle from Mexico

 

Looks like an Iron Cross Blister Beetle?
Wed, Nov 12, 2008 at 11:44 AM
We found this beetle in El Cañon de Guadalupe which is between Tecate & Mexicali in Baja California 11-08-08. We saw alot of these getting together on rocks. We looked thru the archives and found the very similar Iron Cross Blister but the wing case doesn’t look the same nor the color of its head. It’s color is more of a dark rich red not a bright.
Macajr
El Cañon de Guadalupe which is between Tecate & Mexicali in Baja California.

Blister Beetle
Blister Beetle

Hi Macajr,
We agree that this is some species of Blister Beetle, but we do not recognize it. We can’t even decide what the genus is. We will try to contact Eric Eaton for assistance.

Blister Beetles
Blister Beetles

Hi:
I’m relatively certain this is a species in the genus Tegrodera, just not as ornate as the ones from the southwest U.S.
Eric

Letter 11 – Unknown Blister Beetle may be European import

 

Who’s eating my marigolds?
July 21, 2009
Hello! These guys arrived 3 days ago. I thought they were lightning bugs at first. The are buried in each marigold bud and sucking the life out of them. Like a plague of locusts, they have destroyed all the blooms, and there were many! We’ve used several different repellent sprays, nothing keeps them away for long. Thank you for caring! It is appreciated. (Been searching the web for hours to no avail.)
Joanie B.
Eastern Shore of Maryland (Willards, MD)

Unidentified Blister Beetle
Unidentified Blister Beetle

Hi Joanie,
This is a Blister Beetle in the family Meloidae, but we have not had any luck identifying the species on BugGuide.  Adult Blister Beetles often feed on flowers and foliage, but in the larval form, they often have complex parasitic life cycles with hosts that include bees and grasshoppers.  According to BugGuide:  “Pressing, rubbing, or squashing adult blister beetles may cause them to exude their hemolymph (“blood”), which contains cantharidin. This compound causes blistering of the skin, thus the name blister beetle. Accidental or intentional ingestion of these insects can be fatal. There are documented incidents of horses dying after eating hay in which blister beetles were inadvertently baled with the forage. Watch that curious children do not attempt to put these beetles in their mouths. The external use of cantharidin, commercially known as ‘Spanish fly,’ the supposed aphrodisiac, is likewise discouraged.”  We hope one of our readers will be able to supply a species identification, or at least a genus identification.

Unknown Blister Beetle
July 23, 2009
Hi Daniel:
It does look like a blister beetle and I can’t claim to be an expert, but this looks a lot like a species of Epicauta, particularly E. hirticornis. The problem is that this is an Asian species and I haven’t found any record of it becoming an invasive in North America. There are a few other red headed species in the genus but none appear to be endemic to the USA; in fact I haven’t been able to find any North American blister beetle that looks quite like Joanie’s photo. I may be on the wrong track here, or it may be possible that these guys do not belong. I think I will keep looking, but this looks like a job for a real expert. Regards.
Karl

Update from Karl
Hi Daniel:
Can I retract? Some further searching did yield one indigenous species that looks like Joanie’s blister beetle, Epicauta trichrus, although the overall shape and some of the coloration still don’t look quite right. I couldn’t find much information about this species but it has been recorded from Massachusetts, so why not Maryland. I found it on Bugguide.net (where else) – I don’t know how I missed it first time through. In fact, the Bugguide site has a second species. E. atrata, that also looks similar, although apparently the head is usually black and only sometimes reddish behind the eyes. Although to me Joanie’s photo still looks more similar to some of the Eurasian species it makes sense to take the more conservative approach and assume that it is not an introduced species. Regards.
Karl

Thanks Karl,
We looked at those two species and decided they were not Joanie’s beetle, but we may be wrong.

Letter 12 – Longhorn Beetle from Spain: Vesperus xatarti

 

What is this Bug!
Location: Spain, Murcia Region
March 9, 2011 1:37 pm
Hi, Our friend is seeing a lot of these lately on his patio and we are wondering what they are? He lives in Spain, Murcia Region in the countryside, spotted them at end of February.
Can anyone help?
Thanks
Signature: Scrumpy

Vesperus xatarti

Dear Scrumpy,
We haven’t the time right now to research this fully, but we are posting your photo regardless.  We believe this is a Blister Beetle in the family Meloidae, though we would not rule out that it might be another soft winged beetle like a Soldier Beetle or a False Blister Beetle.

Correction:  September 7, 2013
Thanks to a comment from Chema, we have found a link to a female Longhorn Borer Beetle,
Vesperus xatarti, on Dave’s Garden which matches the image in this posting.

Letter 13 – Unknown Blister Beetle

 

Gunmetal-colored blister beetle?
Location: Albemarle County, Virginia
July 20, 2011 3:36 pm
Found this on a grapevine. Gorgeous matte gunmetal coloring. Guessing its a blister beetle but unsure.
Signature: Karl Hambsch

Blister Beetle

Hi Karl,
We concur with your guess that this is a Blister Beetle, and furthermore, we believe it is in the genus
Epicauta based on the information provided on BugGuide, but the species identification is proving to be elusive.  Numerous species in the genus Epicauta are gray in color, and there seems to be some variation in the tone within the species as well as overlap between the species.  If you browse the genus Epicauta on BugGuide, you will see our quandary, especially since there are also subgenera to consider.  You may try submitting your images to BugGuide and have the Blister Beetle expert Dr. Pinto take a stab at a species identification.  Here are the guidelines posted on BugGuide for the types of details he likes to see in field photos to maximize the chances of a proper species identification:  “There is no general recipe. For species ID of some we need to see palpi; for others its tibial spurs; for others it may be hind coxae. For the Caviceps Group the head capsule may be important. These features are not easily documented in field photos. In general, for the subgenus Macrobasis which includes many southwestern species we should have males. Males for all groups are generally best unless the species has a unique color pattern or a unique shape. Fortunately genitalia are of little to no use in Epicauta. Many common Epicauta are simply difficult to identify from photogarphs – field photos are poor substitutes for having a specimen in hand. It seems that it would eventually be worthwhile to photograph authoritatively identified material in museums – virtually all the US species of Epicauta could be done rather easily. Field photos seem to be an inefficient way to get our fauna documented for the non-specialist.”

Blister Beetle

Letter 14 – Unknown Blister Beetle

 

Black Beetle
Location: 15 miles west of Eugene, Oregon
November 11, 2011 2:31 pm
Dear Mr. Bugman,
Could you help me identify this insect that is eating my zinnias (petals only, receptacles need not apply) with what I can only term as orgiastic abandon. Although they seem similar to blister beetles, I can handle them with no ill effects. Thank you for your input.
Yours entomologically
Signature: zekenzoey

Blister Beetle

Dear zekensoey,
While we cannot be certain of the species, we are confident that this is a Blister Beetle in the family Meloidae.  There are several black Blister Beetles in the genus
Epicauta including Epicauta pennsylvanica, the Black Blister Beetle, however, it is not reported on BugGuidefrom Oregon.  The elytra appear to be too smooth to be the Punctate Blister Beetle, Epicauta puncticollis, which ranges in Oregon according to BugGuide.

Blister Beetle

  We will do additional research to see if we can determine a species.

Blister Beetle

Eric Eaton responds to our identification request
Daniel:
No, I don’t, but Jacques Rifkind might.  I thought I had his e-mail but apparently not handy.  Give me another day or so?
Eric

 

Letter 15 – Plague Soldier Beetles, NOT Blister Beetles from Australia

 

I have a bug infestation
Location: Hawthorn, Australia, 3123
March 3, 2012 8:50 pm
Hello, I have an infestation in my fromt garden in Melbourne, Australia, and I am unsure what I can do about it.
Signature: Thanks, Peter Schwarcz

Blister Beetles

Dear Peter,
This appears to be a species of Blister Beetle in the family Meloidae, however, we are not having any luck with a more specific identification.  Blister Beetles are seasonal and sometimes appear in great numbers defoliating plants.  Blister Beetles exude a substance known as cantharadin that is known to cause blistering in sensitive individuals.  We do not give extermination advice.

Hey guys. I don’t think they are blister beetles, I think they are Plague Soldier Beetles. They congregate to mate generally, bit of an orgy going on in the garden.
http://www.brisbaneinsects.com/brisbane_clickbeetles/PlagueSoldierBeetle.htm
Trevor

Thanks for the correction Trevor.

Letter 16 – Yellow Crescent Blister Beetle

 

Subject: Beetle With Ribbons on Back
Location: Austin, TX
March 27, 2013 11:22 am
This bug was near a live oak tree, March 2013 in Austin, TX
Signature: Steven Landry

Identified. Yellow Crescent Blister Beetle. Thanks 🙂

Yellow Crescent Blister Beetle
Yellow Crescent Blister Beetle

Hi Steven,
We were browsing through the Blister Beetle pages on BugGuide before stumbling upon the Yellow Crescent Blister Beetle,
Pyrota insulata, because we didn’t realize you had already identified it.  According to BugGuide:  “Adults feed on nectar, mostly Honey Mesquite (Prosopis glandulosa) though also observed on Rattlesnake Master (Eryngium yuccafolium) and probably others” and “Attracted to lights, occasionally in large numbers.”  Greg Lasley Nature PHotography has a nice series of photos of a Yellow Crescent Blister Beetle on Lupine.  We find your cropping odd, but vaguely amusing.  Since we will be away from the office for several days, we are postdating your submission to go live in our absence. 

Lol! Thanks. I cropped it that way to try to get google image search to match the bug and not the wood planks!

We hope it will give our readers a laugh or at least a smile on April Fool’s Day.

Letter 17 – Spotted Blister Beetle

 

Subject: Soft bodied, light green spotted bug
Location: Utah, West Desert
July 27, 2013 9:40 pm
I have not been able to identify this bug via Google images, FB post in a permaculture site or in any of the books I have at home or researched at the Library. So, if you are able to identify this bug I would have to answer Yes, you are an expert!
Signature: Lisa

Spotted Blister Beetle
Spotted Blister Beetle

Hi Lisa,
We didn’t even notice the challenge you baited us with until we correctly identified your beetle as a Spotted Blister Beetle,
Epicauta normalis (or Epicauta maculata), which we first located on the Utah Pests page of the Utah State University Cooperative Education site and then confirmed on BugGuide.  According to Utah Pests, which mentions the Spotted Blister Beetle is one of the most common members of the Blister Beetle family Meloidae in Utah:  “Alfalfa growers and livestock owners should always be concerned with blister beetles.  These beetles belong to the family Meloidae and produce cantharidin, a chemical toxic to people and animals. Smashing one of these beetles against the skin can lead to painful blisters and swelling.  A recent incident with alfalfa hay infested with blister beetles resulted in the death of a horse, which are particularly sensitive to this beetle’s toxin.  When livestock eat hay containing cantharidin the gastrointestinal and urinary tracts become irritated and complications can lead to death.  If blister beetle poisoning is suspected (symptoms include blisters and colic among others) contact a veterinarian immediately.”  There are several other very similar looking species also called Spotted Blister Beetles, including Epicauta maculata, which is also pictured on BugGuide.

Letter 18 – Spotted Blister Beetle

 

Subject: Type of blister beetle??
Location: Central New Mexico
June 13, 2016 8:07 pm
Hello! We have suddenly noticed thousands of these small beetle type creatures in and around our barn during mid June. We live in Stanley, New Mexico, which is about 50 miles east of Albuquerque and about 45 miles south of Santa Fe. A friend told me they are blister beetles which I know can be very dangerous for horses. I’m hoping she is incorrect and that you can reassure me they are harmless little beings ?. They seem to be everywhere. Thanks!!
Signature: Kristy

Spotted Blister Beetle
Spotted Blister Beetle

Dear Kristy,
This is indeed a Spotted Blister Beetle,
Epicauta pardalis, based on images posted to Alexander Wild Photography and to BugGuide.  According to PetMD:  “Blister beetles are extremely toxic when ingested by horses: as few as five to ten beetles may be fatal to a horse.  The cantharidin toxin affects many bodily systems.  It is extremely irritating to the digestive tract and causes blisters and erosions from the lips and tongue all the way through to the lining of the intestines, which causes abdominal pain (colic) and diarrhea.  This toxin also causes damage to the kidneys and the heart.”  It is our understanding that problems occur when Blister Beetles are feeding on alfalfa that is harvested to provide feed, and not from horses eating Blister Beetles that might be found near stables.  This is a new species of Blister Beetle for our site.

Spotted Blister Beetle
Spotted Blister Beetle

Thanks so much for the info Daniel!
Kristy

Letter 19 – Red Eyed Blister Beetle from Spain

 

Subject:  Some find similar to d. coach horse/oil beetle(Staphylinidae)
Geographic location of the bug:  Granada, Spain
Date: 05/22/2018
Time: 10:09 AM EDT
Your letter to the bugman:  Hello Dr.
Found “she” on a basin in Sierra Nevada 20 days ago, had amazing size about 7cm long and due to the fact rove beetles are the biggest branch +64000 described and +800 just in GB its kind difficult to name it. May you help me to find out?
How you want your letter signed:  Dr Pachanga

Blister Beetle

Dear Dr. Pachanga,
This is not a Rove Beetle, but rather a Blister Beetle, and its red eyes are startling.  We wish your close-up had more clear details.  We believe we have correctly identified it as Berberomeloe insignis thanks to images by Peter Greenwood on FlickR here and again here on FlickR.

Blister Beetle

Letter 20 – Spotted Blister Beetle

 

Subject:  Beetle
Geographic location of the bug:  Ellivott, Colorado
Date: 06/08/2018
Time: 08:42 PM EDT
Your letter to the bugman:  I would like to know what these beetles are eating up my garden
How you want your letter signed:  Lisa Rascon

Spotted Blister Beetle

Dear Lisa,
We are quite confident that we have identified your Blister Beetle as a Spotted Blister Beetle,
Epicauta maculata, thanks to images posted to BugGuide.  The larvae of Spotted Blister Beetles feed on Grasshopper eggs, but adults are plant feeders as you have experienced.

Letter 21 – Unidentified Blister Beetle from India

 

Subject:  Please help me with identification of this beetle
Geographic location of the bug:  Udaipur, Rajasthan, India
Date: 08/14/2018
Time: 01:16 AM EDT
Your letter to the bugman:  Please identify the yellow beetle. Is it a blister beetle if so the species please
How you want your letter signed:  Shakeela

Blister Beetle

Dear Shakeela,
While we concur that this is a Blister Beetle in the family Meloidae, we cannot provide a more specific identification at this time.

Letter 22 – Spotted Blister Beetle in Washington

 

Subject:  Spotted Blister Beetle
Geographic location of the bug:  Tonasket WA
Date: 07/12/2021
Time: 10:20 PM EDT
Your letter to the bugman:
I’ve been pulling pigweed for 4 weeks and about 2 weeks ago this mass of beetles show up. Hundreds and hundreds, practically overnight.They don’t bite or sting or eat anything I’m trying to garden. I don’t bother them. 4-5 days ago, I’m weeding and my arm starts to itch drastically. I look at the spot, not a bump, not a rash, but a blister!.Still, no idea as to what. 3 days later, aha moment. Turns out blooming alfalfa and pigweed family are a favorite food of adult blister beetles. Get rid of it and the beetles will eat your garden. YAY! I don’t have to weed anymore! There are over 7,000 varieties. Average behavior, adults live about 3 months June to Aug., lay eggs in the dirt, and the larvae spend the rest of summer, fall, winter and spring eating grasshopper eggs, (sometimes bees if they can find them) and hibernating (? is that the word?) The blister is truly awe inspiring. And, purportedly, 6 grams of dead crushed dried beetles in one serving of alfalfa hay eaten by a horse can kill the horse. Wild Birds find them delicious, (I read). The blistering agent survives to irritate the entire digestive tract in most mammals. They usually survive, but may get sick. I’ve been seeing grasshoppers, so maybe the beetles know something about the future I don’t. They don’t bother me and they eat grasshopper eggs and pigweed! Yay, go blister beetle.
How you want your letter signed:  Cathy

Spotted Blister Beetles

Dear Cathy,
We love, love, love your submission.  It is awesome that you have done so much research in the effort to make your gardening more labor efficient.  Blister Beetles (including the Spotted Blister Beetle,
Epicauta maculata, which is pictured on BugGuide) do have interesting and complex life styles, and many members of the family are able to excrete the compound cantharadin which can cause blistering in human skin and is also the active component in the alleged aphrodisiac Spanish Fly which is made from the ground bodies of a green European Blister Beetle, Lytta vesicatoria.

Letter 23 – Unidentified Blister Beetle from New Mexico might be Eupompha fissiceps

 

Subject:  Lytta beetle
Geographic location of the bug:  Northern Chihuahuan Desert
Date: 07/16/2021
Time: 08:11 PM EDT
Your letter to the bugman :  I am an undergraduate at the University of New Mexico and I am currently working in a lab that studies ecological relationships. I am very interested in beetles and I am hoping to do research on them for my master’s. While out doing field work I came across this beautiful guy, I was able to determine that it belongs in the genus Lytta, but I am unable to identify a species. Any insight would be helpful and much appreciated!
How you want your letter signed:  Emily

Unidentified Blister Beetle

Dear Emily,
Blister Beetles are indeed fascinating.  This does appear to be a member of the genus Lytta, and it resembles the Master Blister Beetle, though it is lacking the red thorax.  The closest match we could find on BugGuide is the Red Eared Blister Beetle,
Lytta auriculata, but we are not convinced that is your species.  Your individual appears to have short, textured, green elytra.

Update:  July 20, 2021
Frequent contributor Cesar Crash from Insetologia believe this might be Eupompha fissiceps which is represented on BugGuide.

Daniel,
I was able to ID this guy as Eupompha fissiceps
Emily Grant

Authors

  • Bugman

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

    View all posts
  • Piyushi Dhir

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

    View all posts
Tags: Blister Beetles

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