Ground Beetle Bite: Are They Dangerous? Unraveling the Mystery

Ground beetles are a diverse group of insects that play an important role as predators in various ecosystems. These beetles, belonging to the family Carabidae, are generally found in agricultural and garden settings, and some species are commonly spotted in or around homes. While both adult and larval forms of ground beetles are known to be predators, their bite is a topic worth exploring to understand if they are potentially harmful to humans.

The majority of ground beetles do not pose a significant threat to humans. However, it is worth noting that some species, like the rove beetle, soldier beetle, and tiger beetle, can deliver a painful bite when handled, as mentioned by the University of Maryland Extension. It is best to avoid handling these insects in order to minimize any potential risks.

In most cases, ground beetle bites are not dangerous to humans. The pain experienced from their bites is usually mild, and there are no known venomous species that could cause more significant health concerns. Nevertheless, it is important to practice caution and refrain from attempting to handle these creatures without proper protection.

Ground Beetle Basics

General Description

Ground beetles are a group of beetles belonging to the family Carabidae in the order Coleoptera. They are usually small to moderate-sized insects, ranging from 1/8 – 1/2 inches long. Most species are black or brown, but some can display iridescent and metallic colors. These beetles have prominent legs and antennae, as well as noticeable mandibles (jaws).

Geographical Distribution

Ground beetles can be found worldwide, with a significant presence in North America and the Midwest region. There are about 34,000 species globally and hundreds of species in the Midwest alone.

Habitat and Environment

These insects typically reside in various environments such as:

• Forests
• Fields
• Gardens
• Agricultural settings

Ground beetles thrive in these habitats due to the abundance of prey, including insect larvae and other small insects.

Life Cycle and Reproduction

The life cycle of ground beetles consists of four stages: egg, larva, pupa, and adult. The entire process can take up to 4 years to complete. Both adult and larval forms can overwinter in the soil, offering protection from harsh weather conditions.

Comparison Table:

Recognizing Ground Beetle Bites

Physical Appearance of a Bite

• Small, red bump
• Minor inflammation around the bite

Ground beetle bites often result in a small, red bump on the skin. Surrounding the bite, there may be minor inflammation.

Pain and Symptoms

• Mild pain or discomfort
• Temporary itchiness

Bites from ground beetles generally cause mild pain or discomfort. You may also experience temporary itchiness around the bite.

Duration and Healing Process

• Self-healing within a few days
• Effects are not long-lasting

In most cases, ground beetle bites heal on their own within a few days. The effects from these bites do not typically last long.

Comparison Table

As a defense mechanism, ground beetles might bite. However, their bites are typically not harmful and result in a minimal, temporary experience of pain.

Ground Beetles vs. Other Common Beetles

In this section, we will explore the differences between ground beetles and other common beetles, focusing on carpet beetles, leaf beetles, weevils, and blister beetles.

Carpet Beetles

Carpet beetles are small pests that can cause damage to fabrics, carpets, and stored goods. Some key characteristics of carpet beetles include:

• Round, oval-shaped body
• Measuring between 1/8 and 1/4 inches long
• Brown or black in color with various patterns

Unlike ground beetles, carpet beetles do not possess strong mandibles and are not predatory.

Leaf Beetles

Leaf beetles are known for feeding on the leaves of plants and can be common garden pests. Some unique features of leaf beetles are:

• Wide range of colors and patterns
• Measuring between 1/8 and 1/2 inches long
• Characteristic ridges, punctures, or dimples on their wing covers

Ground beetles are distinguished from leaf beetles by their flatter body shapes and their preference for preying on other insects instead of plant material.

Weevils

Weevils are a diverse group of beetles known for their elongated snout and distinctive antennae. Key characteristics of weevils are:

• Elongated snout used for feeding and laying eggs
• Antennae bent in an elbow shape
• Hind legs adapted for jumping

Ground beetles and weevils differ in appearance, with ground beetles being flatter and lacking the elongated snout.

Blister Beetles

Blister beetles contain a toxic substance called cantharidin, which can cause skin irritation and blisters if handled. Identifying features of blister beetles include:

• Narrow, elongated body shape
• Measuring between 1/2 and 1 inch long
• Soft, flexible wing covers

Ground beetles are generally less harmful than blister beetles, as they lack the defensive chemical toxins and are not known to cause welts or burning sensations when handled.

Ground Beetle Behavior and Nuisance Prevention

Attracted to Light and Nocturnal Activity

Ground beetles are nocturnal insects, which means they are most active during the night. They are often attracted to light sources, such as outdoor lighting fixtures. To reduce the likelihood of these beetles becoming a nuisance around your home, consider implementing the following measures:

• Use yellow or sodium vapor bulbs in outdoor lighting fixtures, as they are less attractive to most beetles
• Shield outdoor lights to direct light downward, reducing its visibility to beetles

Feeding Habits and Predatory Role

Ground beetles are important predators in various ecosystems, playing a role in controlling pest populations. Their diet primarily consists of other small insects and arthropods, like ants and spiders. They may also consume seeds and decaying vegetation. Ground beetles are typically beneficial creatures for gardens due to their predatory role, controlling pests that may harm plants.

Entry into Homes and Foundations

During the fall season, ground beetles may seek shelter indoors, entering through cracks, doors, and windows. It’s essential to prevent them from invading your home to avoid potential bites. Although their bites are not dangerous to humans, they can still be uncomfortable. Here are some actions to take to minimize the chances of ground beetles entering your home:

• Seal gaps and cracks around doors, windows, pipes, and foundations
• Store firewood, logs, and debris away from the exterior of your home
• Keep door and window screens in good condition to block entry points
• Install door sweeps to close gaps beneath doors
• Reduce excessive moisture around foundations by improving drainage

It is essential to remember that ground beetles are generally harmless insects, providing ecological benefits, and any bite discomfort from them should be mild and short-lived.

Dealing with Ground Beetles

Natural Predators and Environmental Control

Ground beetles act as natural predators and are beneficial in gardens and fields, as they prey on pests such as slugs, snails, and other insects. To attract these beetles, plant a variety of vegetation to provide them with cover and food sources. For example, mulch and leaf debris can create a healthy environment for these beetles to thrive.

Prevention and Exclusion Tips

To prevent ground beetles from entering your home:

• Seal gaps in the foundations and around doors or windows.
• Store firewood away from your home.
• Remove any debris around your home’s exterior.

These simple steps can help you keep these insects outdoors where they can continue to be beneficial to the environment.

Pesticides and Chemical Control

In general, using pesticides is not recommended for controlling ground beetles. These beetles are beneficial insects and aid in controlling pests in the garden or field. If you must use a pesticide, proceed with caution and carefully research the product’s efficacy and environmental impact.

Non-Chemical Options and Traps

If you need to control ground beetles in specific areas, consider using non-chemical methods such as:

• Sticky traps: Place these in problem areas to capture beetles without harming beneficial insects.
• Manual removal: Collect beetles using a sweep net or by hand (wearing gloves to avoid bites).

Remember, ground beetles are essential for a healthy environment, but it’s crucial to recognize when they become a nuisance and respond accordingly while maintaining their beneficial role in agriculture and gardens.

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 – European Ground Beetle in Canada

Subject: Violet ground beetle?
Location: Lower Laurentians, Quebec
May 4, 2017 5:58 am
Hi
is this a violet ground beetle? I found lots of them on my garden now the snow has cleared here in Quebec, Canada and I read that they eat slugs so I’m very excited. However I just wanted to check it is not some other type of beetle which is going to eat my plants?
Many thanks,
Signature: Anne

Dear Anne,
We are curious where you discovered that this beetle is called a Violet Ground Beetle because that is not a common name used on BugGuide where we believe we have correctly identified this as a European Ground Beetle, Carabus nemoralis, and according to BugGuide its range is:  “n. US & Canada, absent from Great Plains (BG data)  native to Europe, adventive in NA (in the east: NF-MN-ne.VA; in the west: BC-CA to AB-UT; isolated in the Saskatoon area, SK).”  According to Encyclopedia of Life:  “This species, in the subgenus Archicarabus, is a European introduction. Black or dark piceous, upper surface more or less cupreous or greenish bronze, sides of prothorax, and often elytra, usually violaceous. Elytron with three rows of foveae and on each interval with suggestion of five ridges, so irregular and confluent as to give a scaly appearance. Length 21 to 26 mm.”  According to Ground Beetles of Ireland:  “A very eurytopic species, clearly favoured by human activities and widespread in gardens, parks, pastureland and woods in lowland areas.”  According to thewcg.org.uk:  “Adults spend the day under loose bark or among deep plant litter, emerging at night to forage over a wide area, usually on grass or among litter but they also ascend mossy tree trunks. Prey includes slugs and snails, woodlice, millipedes and centipedes. Adults are active from early spring, breed in the summer, and persist into the autumn. ”  We are still curious where you found the common name Violet Ground Beetle because we have not found it used in relation to this species.

Letter 2 – Ground Beetle from Greece

UNKNOWN INSECT
Location: Central Greece Mt. Tymfristos
April 7, 2011 12:13 pm
I cant’ find this insect.
It seems like ”procerus violaceus” but there are many doubts.
Please help me !!
Signature: Elias

Hi Elias,
Though this is definitely a Ground Beetle in the family Carabidae, we are uncertain of the species.  The name you suggested is an obsolete name, and you may be searching in older texts.  The genus Procerus is now listed as Carabus, and that is a likely classification of your insect.

Ed. Note: We received a comment clarifying the error in our previous response.

Letter 3 – Carabus auratus: Ground Beetle from France

What is it?
Hi,
We live in Provence in the south of France. We found this bug in the grass on Saturday morning. Do you know what it is, we could not id it from our books? We think it rather beautiful though.
Kind regards
Annabelle Hill

Hi Anabelle,
Several months past we received an image of this lovely Ground Beetle from Vermont, and at that time we were unaware that Carabus auratus had been introduced to the U.S. Thanks to you, now we have a lovey photo of it on its native soil.

Letter 4 – Mating European Ground Beetles

large beetle identified
Location: Pickering Ontario Canada
April 27, 2011 12:41 pm
Hi, I sent you a photo yesterday of a large blackish beetle with blue ”trim” that I thought might be a carrion beetle. I think I’ve now identified it as a European Ground Beetle, carabus nemoralis, and have been delighted to learn that it is a voracious eater of snails and slugs (and less happily, worms). I’ve since found several more of these big beetles in my garden, so perhaps I’ll be slug-free this year. How common is this beetle in southern-central Ontario? I’m just east of Toronto. Thanks!
Signature: Pat V.

Hi Pat,
Your letter arrived when we were out of the office on holiday, and this followup email arrived just as we returned to a very full mailbox.  Alas, we are not able to respond to all the mail we received, but we are thrilled that you self identified your mating European Ground Beetles and we love your photograph.  BugGuide has a nice information page on the European Ground Beetle.

Letter 5 – European Ground Beetle

Ground beetle?
Location: Newfoundland, Canada
October 22, 2011 11:59 am
Hey! I’m a wildlife student and I’ve been searching for a species from the order Coleoptera to write a report on. I’ve stumbled upon this guy; rather he stumbled upon me while attempting to hide under my bare foot (jeesh!). I’m new to beetles and haven’t the experience in identifying them. Hoping you can help 🙂
Signature: Cole

Hi Cole,
This is most certainly a Ground Beetle.  Furthermore, we believe it is an introduced species, the European Ground Beetle, Carabus nemoralis.  We matched your beetle to a photo on BugGuide.

Letter 6 – Ground Beetle from Serbia

Identification of Beetle needed
Location: Belgrade, Serbia
April 2, 2012 10:37 am
I took this photo yesterday (April 1) of this beetle. It was living under the bark of a big tree stump. I live in Belgrade, Serbia, which is south eastern Europe. Any idea what genus or species?
Signature: Bill Kralovec

Hi Bill,
We believe we have relatively quickly identified your Ground Beetle as Carabus granulatus, a species found throughout Europe and west into the northern parts of Asia.  We also learned the species was introduced to North America.  You can compare your photo to this example on the Ground Beetles of Ireland webpage.

Daniel,
You guys rock!!!!!! Thanks a lot. I can now upload the photo to my Serbian nature web site. I’ll also give you a plug with my son’s first grade teacher. They are doing a unit on “mini-beasts” and my son is fascinated with insects. I hope to steer him into a career in the natural sciences, or at least a life-long interest in the nature. He was wondering what type of beetle it was.
Regards,
Bill Kralovec, Secondary Principal, International School of Belgrade

Letter 7 – European Ground Beetle

Subject: Beetle with purple spots
Location: Vermont
May 15, 2013 5:49 pm
Hi Bugman!
I am in northern Vermont. I found a beetle outside on the playground with my toddler class. Can’t find it anywhere to identify it!
Signature: Amy

Hi Amy,
This lovely beetle is a European Ground Beetle, Carabus nemoralis, and you can read more about it on BugGuide.

Thanks for getting back to me so quickly. Do you know if these are a threat to little hands? or do these ones secrete anything stinky? LOL   Thanks so much again!!

Hi again Amy,
Ground Beetles are predators that have strong mandibles, and it is possible that they might nip a person, but they have no poison and they are not dangerous.  We doubt they could even draw blood.  Smell is so subjective, and folks with sensitive noses might find them stinky, but we have not read anything about them using scent as a defense.

Letter 8 – European Ground Beetle

Subject: Large Black and Blue Beauty
Location: Bellingham, WA Pacific NW
June 30, 2015 12:51 pm
Found this fellow under a moist hanging flower basket that I had set in the shade. Beautiful large black sheened beetle with two distinct blue spots. Should have measured but over an inch I’d say. Can’t find him on the web.
Signature: Michelle

Dear Michelle,
Your European Ground Beetle, Carabus nemoralis, is quite beautiful, and we can’t quite bring ourselves to consider it an Invasive Exotic species, though we speculate it might be displacing related species that are native and that occupy the same niche on the food chain, and they might also be eating caterpillars of endangered species, but on the flip side of the coin, they may be contributing to the diets of insectivores or all phyla.

Letter 9 – European Ground Beetle in Alaska

Subject: Beetle ID
Location: Anchorage, AK
July 31, 2016 10:37 am
Although born and raised in Anchorage, this year is the first I’ve come across this beetle. I can not seem to find any Alaskan reference (picture) on the web, so I’m turning it over to you. The sample photo’d was found while working in a flower bed. A couple of more came up while raking out some heavy moss in the yard. (They seemed to be under the moss.) They definitely do not like light and run until they can hide their body under something, or can burrow into loose dirt or a crack. (This one was very hard to photograph.) They are at least 3/4 inch long and possibly closer to an inch. Other than the size, the iridescent horns on the rear edges of thorax is the most distinctive feature.
Signature: Rich Johnson

Dear Rich,
Based on this BugGuide image, we are confident this is a European Ground Beetle, Carabus nemoralis, a species that was introduced from the Old World.  Its North American range, according to BugGuide is:  “n. US & Canada, absent from Great Plains (BG data) native to Europe, adventive in NA (in the east: NF-MN-ne.VA; in the west: BC-CA to AB-UT; isolated in the Saskatoon area, SK).”  According to the Natural History of Southeast Alaska:  “Introduced species so far (as of 2011) known only from Sitka, where it does not seem to be uncommon” and “First reported from Alaska in Sitka, adults seem to be relatively common around yards/gardens by May and into June, though not later in the summer.”

Thank you so much for the ID; the photo attached to your link is my guy.
Given the climate around south central I’m not too surprised they are this far north of Sitka.
We’ve also just had two of the mildest winters and warmest summers that I can remember.
(And I’m Anchorage born & raised, and over 60.)
I’m sure they are not seen much due to their apparent aversion to daylight, which can be tough to avoid in the summer up here.
All the best, and thank you again.
Rich