Ground beetles are fascinating insects that play a vital role in the ecosystem as predators. These insects, belonging to the family Carabidae, can be found in various agricultural and garden settings, and may even be the most numerous predators in certain systems UMN Extension. With over 34,000 species worldwide and hundreds of species present in the Midwest alone, ground beetles exhibit a diverse range of appearances and behaviors Wisconsin Horticulture.
An adult ground beetle typically exhibits a glossy black or iridescent color, but some members of this family can also be seen sporting green, yellow, or orange hues BioKIDS. Their flattened bodies display grooves or rows of punctures along the wing covers, and their long legs allow them to move quickly across the ground in pursuit of prey. The larvae of ground beetles possess large heads and a somewhat hairy appearance.
Although ground beetles may sometimes be viewed as a nuisance when they unintentionally find their way into homes, they are beneficial insects that feed on other insect larvae Iowa State Extension. This helps to maintain a balanced ecosystem and can even aid in pest control within gardens and agricultural fields.
Overview of Ground Beetles
Ground beetles belong to the family Carabidae, a diverse group of insects with over 34,000 species worldwide. They are predatory insects commonly found in agricultural and garden settings, where they serve as important allies in controlling pests.
Ground beetles are generally small to moderate in size, ranging from 1/8 – 1/2 inch in length – with some species growing as large as an inch. They have:
- Flattened bodies
- Obvious mandibles (jaws)
- Long legs (relative to other beetles)
These characteristics allow them to move quickly and hunt their prey effectively. Ground beetle larvae share some similarities with the adult beetles, such as large heads and a somewhat hairy appearance.
Ground beetles come in various colors, including black, green, yellow, and brown. Iridescent ground beetles display different colors when viewed from different angles of light. These variations add to the beauty and diversity of this beetle family.
Comparison Table of Ground Beetles Colors
|Black||Glossy, most common|
|Brown||Matte, commonly found|
Habitat and Behavior
Ground beetles can be found in various environments, such as forests, fields, and gardens. Some key features of their habitats include:
- Moist or damp areas
- Leaf litter or debris
- Rocks and logs to hide under
These insects are beneficial in controlling pests as they are important predators in agricultural and garden settings.
Ground beetles are mostly nocturnal, which means they are active during the night. Their nocturnal behavior allows them to:
- Avoid being detected by predators
- Hunt for prey more effectively at night
Overall, ground beetles are essential contributors to controlling many types of pests and maintaining ecological balance.
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 – Likely Beetle Larva from the Philippines
Subject: Creepy centipede-like insect
Location: Cavite, Philippines
May 24, 2015 1:13 am
Hi! My brother found this odd looking centipede in our house. Definitely, this is not a centipede because it only got 6 legs. I tried doing some research but can’t find any match. We’ll really appreciate it if you can help us identify this creature.
Without doing any research, we suspect this is a Beetle Larva, most likely the larva of a Ground Beetle in the family Carabidae. Carabidae of the World has some very similar looking images of a species identified as Carabus (Morphocarabus) karpinskii. This most resembles larvae of the Caterpillar Hunters, a group of large predatory Ground Beetles. We have not had any luck matching your images to online images from the Philippines.
Wow! It’s a larva. It must be a very big beetle then when it matures because this larvae measures around 2 and a half inches.
Thanks Daniel for your response!
We appreciate it.
Letter 2 – Small Beetle from UK is Plaster Beetle
Subject: Is this a Bed Bug?
Location: Newcastle Upon Tyne UK
December 9, 2014 12:46 pm
I have noticed some bites on my legs after a night sleep. It repeated a few times, very itchy and in a specific pattern. From what I read the pattern of bites is like a bed bug bites (in 3 and in lines or triangles). So I decided to get a professional because I couldn’t find anything myself. A person came to view the problem but found nothing. Used his pest liquid in the main areas where supposedly bed bugs are. After a night sleep I had no bites but I found that bug under the mattress. It did not move. I took a picture for the pest control professional but he couldn’t identify the bug. It is around 2mm long. Can you please help me?
This is most definitely not a Bed Bug. This looks to us like some species of Beetle, but we are uncertain how to classify it according to family. Perhaps one of our readers will be able to assist us in this identification.
Update: Plaster Beetle
Thanks to a comment from Cesar Crash of Insetologia, we now know that this is a Plaster Beetle in the family Latridiidae. According to the Natural History Museum site: “It’s a latridiid beetle (Coleoptera: Latridiidae) – aka Plaster beetles. Adults feed on minute fungal spores and are usually found in conditions that are damp. They are a fairly frequent contaminant in shipped goods where the boards on the floor of the shipping container are infested with these beetles. They are not harmful in any way – won’t eat your carpets or floorboards etc. Doesn’t look dissimilar to Eufallia sp.” More information on Plaster Beetles or Minute Brown Scavenger Beetles is available on BugGuide.
Letter 3 – Ground Beetle Larva
Scorpionfly head/Earwig cerci???
December 5, 2009
I am teaching 5th graders some insect basics. In our “catching” class, one of the students caught this insect. This was in the moist dirt outside the school in Anderson, SC, Dec. 4,2009. 18mm, ant.5 or 6 seg., snout-shaped head, thorax 11seg with 6 legs on no. 9 -11, tarsi 3 seg, leathery dorsal surface, pincer (earwig-type) cerci. The head shape and location of legs is confusing.
Otherwise, it just looks like an earwig. Is this some larval form? Pictures are through a microscope. Help!
Anderson, SC, USA
We are requesting assistance from Eric Eaton with the identification of this larval form. We wish you had sent a photo of the entire specimen. You might also want to consider posting a comment to your own query in the event one of our readers supplies an answer.
Identification by Eric Eaton
Thanks to the magnificent close-up images of all the important body parts, I can tell conclusively that this is the larva of a ground beetle, family Carabidae. The two claws on each leg immediately distinguish carabid larvae from very similar rove beetle larvae (family Staphylinidae). Nice work by the photographer!
Letter 4 – Snail Eater, We believe
Subject: Grandson’s bug
Location: Washington state
June 1, 2016 1:52 pm
Charlie collects bugs constantly! He wants to know this one please –
Signature: Thank you
Though we love the image you attached, we wish you had been able to provide an image that shows the dorsal surface of the beetle unobscured by fingers as that would be better for identification purposes. We are disappointed that Insect Identification: Insects and Other Bugs from the State of Washington does not include many Ground Beetles. This is some species of large Ground Beetle in the family Carabidae, but we are uncertain of an exact species. Our likeliest suspect is a Snail Eater, in the genus Scaphinotus, and according to BugGuide: “Feed on snails, slugs. Mandibles specially adapted for insertion into opening of a snail’s shell.”
Thank you so much for the reply – I’ve never seen a child so interested in insects and spiders. We spend a lot of time searching bug books and online sources! Charlie is just 5 1/2 but has been doing this for a couple years. He will be thrilled when I share your email.
Letter 5 – Bombardier Beetle
Subject: Stink Bug?
Location: Raymond, GA
March 17, 2015 11:13 am
I found this bug in the woods, and when I went to take a picture of it, it was partially obscured by leaves. I used a stick to brush the leaves away for a better view. When I did this is “popped” and released some sort of white cloud. After it did that, it scrunched up into a ball, and I was afraid I had accidentally hurt it. I used a leaf to transfer it to a piece of wood, and lo and behold, it sprang up and darted off! While I was relieved, i was wondering what caused it to make that popping noise. I thought maybe a “Stink Bug” of some sort, but couldn’t find any pictures of one that looked similar online, nor, now that I think about it, was there any unpleasant smell. I thought the red coloration was very pretty, but I’m sure other insects take it as a warning. Any idea what this little guy is?
Update: March 19, 2015
Hey, I sent in a letter under the title “Stink Bug?” After doing some research, I think I identified it as the Bombardier beetle (Brachinus species). However, when I looked on your site, all I could find was the False Bombardier beetle. I’m not sure if I misidentified this.
We are so excited you wrote back to us, which prompted us to locate your original email. This was an especially hectic week for our tiny editorial staff and we missed your original submission. We are positively thrilled to be able to include your images of a Bombardier Beetle on our site because as you have observed, we only have images of False Bombardier Beetles, also members of the Ground Beetle family Carabidae, but in a different genus and recognizable by the black, not red head. We are also thrilled with the written observations you provided. The popping sound you heard is explained on BugGuide: “Adults have chemical defenses, ejecting toxic, foul-smelling gases from their abdomen with a loud popping sound. The explosive brew is composed of hydrogen peroxide, hydroquinone, and catalytic enzymes.” Wired has a wonderful article on Bombardier Beetles which incudes: “There are hundreds of species of bombardier beetles all over the world, with various defensive mechanisms. Some have non-explosive, foamy excretions of chemicals, while others like the African bombardier beetle can actually aim their explosive spray in virtually any direction like an angry lawn sprinkler.”
Letter 6 – Bombardier Beetle
Subject: Bug Indentity
Location: Wichita, Ks
January 24, 2017 4:05 am
I found this in washer. My roommate has been issues with bugs. I just wondered what this was because I’ve never seen one before. Thanks!
This fascinating beetle is a Bombardier Beetle in the genus Brachinus. and according to BugGuide: “Adults have chemical defenses, ejecting toxic, foul-smelling gases from their abdomen with a loud popping sound. The explosive brew is composed of hydrogen peroxide, hydroquinone, and catalytic enzymes.”
Letter 7 – Bombardier Beetle from Afghanistan: Pheropsophus catoirei
Subject: Afghan Beetle
Location: Bagram, Afghanistan
August 23, 2016 4:06 pm
Hey. I wondered if you could tell me what this bug was that I caught crawling past my feet in the office when I had no shoes on! I’m sure he means no harm but didn’t want any nasty surprises crawling up my leg so I caught him anyway. I’ve let him go outside now though but still wondering what he was as he looks quite cool!
Signature: Dean, AFG
Your pretty beetle is a Ground Beetle in the family Carabidae, and we believe we have correctly identified it as Pheropsophus catoirei, a member of the subfamily Brachininae according to the Carabidae of the World site. According to BugGuide, Brachininae is the subfamily that includes Bombardier Beetles, a group that have chemical defenses explained on BugGuide as: “Adults have chemical defenses, ejecting toxic, foul-smelling gases from their abdomen with a loud popping sound. The explosive brew is composed of hydrogen peroxide, hydroquinone, and catalytic enzymes.” A very similar looking beetle is pictured on RevolvY where it states: “Bombardier beetles are ground beetles (Carabidae) in the tribes Brachinini, Paussini, Ozaenini, or Metriini—more than 500 species altogether—which are most notable for the defense mechanism that gives them their name: when disturbed, they eject a hot noxious chemical spray from the tip of their abdomen with a popping sound. The spray is produced from a reaction between two chemical compounds, hydroquinone and hydrogen peroxide, which are stored in two reservoirs in the beetle’s abdomen. When the aqueous solution of hydroquinones and hydrogen peroxide reaches the vestibule, catalysts facilitate the decomposition of the hydrogen peroxide and the oxidation of the hydroquinone. Heat from the reaction brings the mixture to near the boiling point of water and produces gas that drives the ejection. The damage caused can be fatal to attacking insects. Some bombardier beetles can direct the spray over a wide range of directions.”
Letter 8 – Caterpillar Searcher from Syria
Location: North Syria
May 2, 2011 6:50 pm
I saw this bug in march-3-2011 at the garden of my home in Aleppo/Syria at 3:30pm
It was crawling on a quince tree .
Can you help me identify it?
Signature: Tamim Houary
Your beetle is a Ground Beetle in the family Carabidae, and we believe it is most likely one of the Caterpillar Hunters in the genus Calosoma. We actually believe this may be the Caterpillar Searcher or Forest Caterpillar Hunter, Calosoma sycophanta, a species that was introduced from Europe to North America to help control the Gypsy Moth according to BugGuide. According to the Carabidae of the World website, the natural range of the species includes Syria. Here are some notes from the Calosoma of the World website: “Notes: Winged diurnal but in some case can be attracted to light at night. It is inhabitant of both coniferous and decidous forests. Adults and larvae are excellent climbers and feed on Lymantridae and Thaumatopoeidae (Thaumatopoea pityocampa Denis & Schiffermuller, Lophirus pini Linné, Thaumetopoea processionea Linné, Lymantria dispar L., Euproctis chrysorrhoea Linné) and other caterpillars infesting trees of genera Pinus, Quercus and Fagus. Adults hunt trunks and treetops during the day and go down to the ground at around sunset and then hide in leaf litter at the foot of the trees.
Captures of active individuals have been noted from April to August. It is not rare to find specimens overwintering in small cavities in the ground.
Calosoma sycophanta is an handsome beetle that has attracted, since the first steps of entomology, the interest of entomologists. It is one of the few Carabidae represented in the volume of Aldovrandi (De Animalibus Insectis Libri septem cum singulorum Iconibus ad vivum expressis 1638: 450, fig. 6) under the name of Scarabaeus viridis. Later Reamour (Memoires pour servir a l’histoire des Insectes, vol. II, 1736: 455 and plate 37 fig. 18) has given an account of its way of life. Subsequently there have been numerous illustrations in books of this beautiful species. It can still be interesting to recall that, because of its rarity in the British Isles, Donovan (The Natural History Of British Insects, vol. XIV, 1810: pl.477) has drawn in its place the Calosoma (Calodrepa) scrutator. This error has been then corrected by Curtis (British Entomology, 1823-1840: pl.330).”
Letter 9 – Mating Warrior Beetles
Subject: Unknown stag beetle?
Location: Raleigh, NC
August 6, 2017 5:51 pm
I found these beetles mating when I was going out for a walk. The blueish lining on the edge of the beetle and the pinchers were very interesting. I’ve searched online for this type of beetle but I found nothing. Please help me identify this beetle.
Signature: Seiya Furukawa
Despite the large mandibles, these are not Stag Beetles. They are Ground Beetles in the genus Pasimachus which Arthur V. Evans refers to as Warrior Beetles in his book Beetles of Eastern North America. A similar looking individual is pictured on Ohio Birds and Biodiversity, and it is called a Blue Margined Ground Beetle, Pasimachus depressus. This image from BugGuide is not too different from your image. BugGuide does not provide a common name, but does provide this description: “Large, black, elytra and pronotum often bordered with blue/violet. Elytra of male shiny, of female dull, neither have striations or punctures. Base of pronotum (next to abdomen margined). Hind tarsus long and slender.”
Letter 10 – Probably Bombardier Beetle from Botswana
Subject: Problem child
Location: Central Kalahari, Botswana
April 20, 2015 1:26 am
I am going through all the bugs that I collected during March and right now I have this little guy, who I would like to think is a species of a Bombadier beetle.
If it is possible I would love to get some help to get the species of the guy. It is a lot similar to Pheropsophus africanus, but with only two yellow/orange spots far back on elytra, which defers from P. africanus.
I hope you can help me 🙂
Your beetle looks identical to an image of a Ground Beetle from Saudi Arabia we posted last year that we believe to be in the genus Pherosophus, and we did link to an image of Pheropsophus africanus. Perhaps one of our readers can confirm or correct that identification.
love how quick you are to reply, huge thumps up for that 🙂
I saw that post, while I was trying to get a name on it… The big
difference between the two is that elytra on my beetle stops right
after the two spots, where P. africanus goes further back and have a
slight yellow band on the edge of elytra.
Thank you for the help so far. I am crossing my fingers to get a species 😀
I have been looking at some other beetles today, and I found this site (http://www.beetlesofafrica.com/beetle_detail.asp?beetleid=610&page=1&count=y) ,
which could be the closest we can get to an answer 🙂
thank you for the help 🙂
Letter 11 – Small Snail Eating Beetle
Subject: Ground beetle?
Location: Speculator, NY
August 2, 2012 10:34 pm
I found this beetle under a rotting log in the Adirondack Mountains of NY (near Speculator, NY). I am wondering if it is some kind of ground beetle, possibly of the genus Scaphinotus?
This is sure a handsome specimen of a Small Snail Eating Beetle in the genus Sphaeroderus. You are correct that it is classified as a Ground Beetle in the family Carabidae. We identified it thanks to photos posted to BugGuide which notes: “The foreparts of their bodies are specially streamlined to fit in the aperture of a snail” and provides this image from the BugGuide archive as a photographic documentation. Your photo is a new genus for our archive.
Thanks for looking into it and letting me know! They are gorgeous beetles.
Letter 12 – Small Snail Eating Beetle
Location: Studley, Virginia
October 24, 2015 2:50 pm
Hi Bugman! Seriously, I love this website!
I saw this beetle outside, and it immediately caught my eye, because it looked different than most black beetles I see.
I looked it up, and the closest I can find is that it looks like it might be in the genus Cychrus.
What do you guys think?
Thanks so much for your effervescent praise. We believe you have correctly identified this Small Snail Eating Beetle to the Tribe level of Cychrini, but the genus Cychrus, according to BugGuide, is found in the Pacific Northwest. Based on this BugGuide image and others posted there, we believe your beetle is in the genus Sphaeroderus, and there are six species in the genus found in your area of the country, according to BugGuide.
Letter 13 – Snail Eater
Big black beetle
October 13, 2009
Saw this big black beetle in September 2009 crawling in the leaf litter of the forest floor just north of Mendocino, California. It was approximately 1.75 inches long from the tip of its head to the rear of its carapace. When I discovered it and started taking photos, it didn’t scurry away; it slowly and methodically crawled away and hid under forest floor detritus.
Thanks for any help info you may have,
This is some species of Snail Eater, a Ground Beetle in the genus Scaphinotus. We don’t feel qualified to take the identification to the species level with the information provided on BugGuide, especially since some species are represented by a single photograph from California. We might suggest that you also submit your photo to bugGuide in the hopes that you can get a species identification.
Update from Eric Eaton
I’d need to see the specimen of the snail-eater to key it out to species….
Letter 14 – Snail Eater
Location: Portland, Oregon
May 5, 2012 11:13 pm
My son found this lively and beautiful bug on a hike in Forest Park in Portland, Oregon, on a shady part of the trail. There are so many distinctive things about this insect, but we are unable to identify it with our guides. My son remembers this bug and wants to know its name so he can call to his friend the next time we go there! Any help would be greatly appreciated.
Determining the order and family are the best way to try to identify an insect species. This is a Beetle and it is subclassified as a Ground Beetle in the family Carabidae. It is one of the Snail Eaters or Boat Backed Ground Beetles in the genus Scaphinotus, and we believe based on the appearance of the elytra or wing covers as well as the documented range that this might be Scaphinotus angusticollis which according to BugGuide is found in : “Humid coastal forests of Pacific Northwest.”
Letter 15 – Snail Eater
Subject: Mystery beetle in a state park
Location: Saint Edward Park, WA state
October 11, 2013 7:53 pm
Hello WTB magicians!
I stumbled onto this site when trying to find out what a local beetle is, and I’m so amazed by it! Thanks for doing this, it looks like a wonderful resource for solving some of the mysteries of the bug world.
The bug I would like to identify is one that I saw recently in abundance wandering the trails of Saint Edward state park in Washington state, USA. My husband and I tried to take a few pictures of them running around on the paths, but they were too fast for any of our photos to turn out, so we gently scooped one into a shallow tupperware dish to temporarily corral it so we could get better shots. (She has already been released outside)
They have long legs and are quite fast. We thought maybe it is some kind of tiger beetle, but we know sometimes those can be pretty aggressive, and this one was not bitey in the least. The photos don’t show it very well with the unnatural light being used, but their abdomen has a rich reddish-purple sheen, and there are little facets around the edge of it that sparkle in the natural light. We didn’t have a ruler handy, but we put a dime near her for an idea of the size.
Thank you so much for your time and effort, I hope you can work your magic on this one! Cheers!
Signature: – A grateful bug enthusiast
Dear grateful bug enthusiast,
We believe we have correctly identified your Ground Beetle as a Snail Eater, Scaphinotus angusticollis (Mannerheim 1823), thanks to swell photos posted to BugGuide. According to BugGuide, their habitat is “Mostly forests, under logs, rocks, in leaf litter” and they “Feed on snails, slugs. Mandibles specially adapted for insertion into opening of a snail’s shell.” Ground Beetle often run quickly as you observed. Tiger Beetles are one subfamily of Ground Beetles, so your comparison is valid.
Letter 16 – Notched Mouth Ground Beetle Larva
funky bug that appears blue
Location: Lawrence Kansas on Sidewalk during October
October 3, 2010 8:20 pm
I found this bug while walking my dogs. It was during a cool (60ºs) and sunny. We are in Lawrence, Kansas. I saw the bug zipping across the sidewalk during the early morning on Oct 2nd.
We believe this is a Beetle Larva, and it appears to be predatory, but we need to do some research before we are certain. We are posting your photo and indicating that it is unidentified and perhaps our readership will be able to beat us to an identification.
Eric Eaton provides an Identification
Looks like the larva of a Dicaelus ground beetle to me:
Pretty strange indeed 🙂
Thanks Eric, for providing a link to the Notch Mouth Ground Beetle in the genus Dicaelus for us. BugGuide has several images of the larva and they do appear to match the photo we received.