Are False Bombardier Beetles Dangerous to Humans? Uncovering the Truth

False bombardier beetles are fascinating insects that have developed a unique defense mechanism to deter predators. They belong to the genus Galerita and utilize formic acid and acetic acid to protect themselves from harm.

This natural deterrent has caught the attention of many due to its striking similarity to the famous bombardier beetles, which are known for their powerful and hot chemical spray.

However, when it comes to interactions with humans, the concern arises whether these false bombardier beetles pose any potential danger.

While their spray is mainly composed of concentrated formic acid, which is unpleasant and noxious to both vertebrates and invertebrates, it is generally less potent than that of the true bombardier beetles.

In fact, the spray from a large bombardier beetle can even be painful to humans. On the other hand, the false bombardier beetle’s defensive spray, though irritating, might not inflict substantial harm on humans in most cases.

Understanding False Bombardier Beetles

Features and Characteristics

False bombardier beetles are insects that share some similarities with true bombardier beetles but have distinct differences in their defensive mechanisms and appearance. Here are some key features of these beetles:

• Head: Thick orange segments coming off the head
• Color: Reddish-brown to black
• Elytra: Hardened forewings that protect the abdomen
• Abdomen: Houses paired glands that produce defensive chemicals
• Antennae: Pair of long, segmented appendages for sensing the environment
• Legs: Six legs used for speedy movement
• Length: Between 0.66 – 0.98 inch

Comparing the false bombardier beetle and the true bombardier beetle:

Habitat and Distribution

False bombardier beetles can be found across various habitats, including forests, grasslands, and gardens. They are nocturnal carnivores, feeding on other insects and smaller arthropods at night.

While these beetles are not particularly dangerous to humans, their chemical defense—consisting mainly of concentrated formic acid, acetic acid, and wetting agents—may cause minor irritation if encountered.

They can spray their defensive chemicals with a high degree of accuracy up to twenty times.

Being adaptable insects, false bombardier beetles can thrive in different environments, but they prefer damp, dark, and organic-rich habitats where they can easily find prey.

Although they do not have the same potent defense mechanism as the true bombardier beetles, they still deter most predators with their noxious spray, allowing them to thrive in their natural habitats.

Behavior and Life Cycle

Diet and Predation

False bombardier beetles, belonging to the genus Galerita, are part of the ground beetle family Carabidae. They are carnivorous arthropods that primarily feed on small insects like caterpillars.

These beetles are efficient predators due to their speed and ability to produce a defensive spray containing formic and acetic acid when threatened. Their spray enables them to fend off potential predators like birds and larger insects.

Nocturnal Habits

False bombardier beetles are nocturnal creatures, meaning they are most active and hunt for prey during the night.

This behavior allows them to avoid daytime predators and take advantage of the moist environment found in woodlands and moist areas at night. They can often be found in places like leaf litter, logs, and under rocks.

Reproduction

Ground beetles, including the false bombardier beetle, mate and lay eggs in their adult stage. Their life-cycle consists of four stages: egg, larva, pupa, and adult.

They live for several weeks during which they reproduce and pass on their genes. Some species of bombardier beetles can survive for several years.

Features of False Bombardier Beetle:

• Carnivorous diet
• Nocturnal habits
• Defensive spray
• Four-stage life cycle

Comparison between False Bombardier Beetle and True Bombardier Beetle:

Defensive Mechanisms and Mimicry

Dischargeable Glands and Chemicals

False bombardier beetles, belonging to the genus Galerita, employ defensive chemicals such as formic acid and acetic acid for protection.

These arthropods possess specialized dischargeable glands that release these acids in bursts when threatened. For instance, it takes about 5 days for them to replenish the formic acid released in one burst.

Their defense system also includes the formation of hydrogen peroxide, which is produced as a byproduct of the reaction with oxidative enzymes in their glands. This adds to their effectiveness in fending off predators.

Some characteristics of these glands include:

• Capable of producing and storing formic acid
• Replenishing spent chemicals within a few days
• Producing hydrogen peroxide as a byproduct

Similarities with Other Beetles

False bombardier beetles are closely related to other ground beetles, and they often display similar traits for defense and predator avoidance.

For example, mimicry is a common tactic among these beetles, as they may resemble other species to confuse or scare away predators.

One such example includes longhorn beetles which might share a similar habitat with false bombardier beetles but have an orange thorax, giving the impression that they possess similar defense systems.

Furthermore, both false bombardier beetles and their ground beetle relatives can be found in habitats such as open woodlands and brush piles, where they prey on other arthropods like spiders.

Features shared by other related beetles:

• Mimicry for predator deterrence
• Similar habitats and dietary habits
• Physical traits like coloring or ridges

While false bombardier beetles and their defenses are primarily effective against predators like spiders, their defensive capabilities are not considered harmful or dangerous to humans.

In fact, these beetles play an essential role as natural predators of various pests, making them an integral part of the ecological balance.

Human Interaction and Potential Danger

Risk of Bites and Pain

False bombardier beetles, belonging to the genus Galerita, utilize a defense mechanism involving the release of formic acid and acetic acid when threatened.

While these chemicals can indeed be irritating, the risk of bites and pain associated with false bombardier beetles is minimal for humans.

• The spray mainly consists of concentrated formic acid, which can cause discomfort.
• Noxious to both vertebrates and invertebrates.

However, an encounter with these beetles generally poses a low risk to humans due to their non-aggressive nature.

Environmental Significance

False bombardier beetles are an important part of the ecosystem, and their presence indicates a healthy environment.

While the defense mechanisms of these insects may cause minor irritation to humans, their overall presence is beneficial as they help maintain balanced populations of other insects.

By protecting these beetles and their habitats, we can preserve their valuable role in the ecosystem.

• Important for maintaining insect populations in the environment.
• An indicator species of a healthy ecosystem.

Conclusion

In conclusion, false bombardier beetles are known for their unique and fascinating defense mechanism and pose minimal danger to humans.

They can spray formic acid spray with high accuracy. However, they are not as dangerous as true bombardier beetles. The spray won’t cause much harm to humans. However, it is wise to be careful.

They play a crucial role in ecosystems as natural predators, contributing to the balance of insect populations. Respecting their role in the ecosystem and minimizing harmful interactions are crucial steps in maintaining overall environmental health.

Reader Emails

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

Letter 1 – False Bombardier Beetle

please identify this bug
March 15, 2010
I found this in my jacket! I don’t want to kill it if it is harmless or useful.
Celeste
Charlotte, North Carolina

Hi Celeste,
This is a False Bombardier Beetle in the genus Galerita.  According to BugGuide, the False Bombardier Beetles can be distinguished from the true Bombardier Beetles by the “Large size, blue/black striated elytra, brown pronotum, legs, palpi.

Head black, unlike the bombardiers, Brachinus, which have a brown head, and are usually smaller (4-15 mm).”  False Bombardier Beetles are beneficial predators with a unique defense mechanism. 

According to the Proceedings of the National Academy of Sciences (PNAS) of the United States of America website: “The carabid beetle Galerita lecontei has a pair of abdominal defensive glands that secrete a mixture of formic acid, acetic acid, and lipophilic components (long-chain hydrocarbons and esters).

Formic acid, at the concentration of 80%, is the principal constituent. The beetle ejects the secretion as a spray, which it aims accurately toward parts of the body subjected to assault. At full capacity, the glands store 4.5 mg of formic acid (3% of body mass), enough for upward of six ejections.”

Letter 2 – False Bombardier Beetle

What is this one?
We have been seeing this bug quite frequently all over our house recently. We had someone come out and take a look at it, and they thought it was some form of boxelder bug.

I think it looks closer to an assassin bug – but not close enough. There is no reference to size in the picture, but they are probably the biggest bug I have ever had in my house. Also, they are very fast. Thoughts?

Thanks for the help,
Kent

Hi Kent,
This is a False Bombardier Beetle, Galerita janus. They can still spray repulsive chemicals, so not sure where the “false” applies!

Letter 3 – False Bombardier Beetle

What is this bug???
Hi Bugman:
I found this bug on the floor of the ground level inside our home last week. Can you please identify and provide some info? We live in Western PA. Thank you.
Marc

Hi Marc,
This is a beneficial predatory ground beetle known as a False Bombardier Beetle, Galerita bicolor.

Letter 4 – False Bombardier Beetle

Beetle Identification
June 9, 2010
This beetle was found in a mixture of garden soil and compost (in a plastic pot on my front porch) in Truro MA. Our local Auduon sanctuary had never seen such an insect here on Cape Cod. My sons and I would LOVE to know what kind he is:)

Thanks Kindly, Cindy Long
Outer Cape Cod, MA

Hi Cindy,
Though you photo is quite blurry, your beetle can be easily identified as a False Bombardier Beetle.  The black head distinguishes it from a true Bombardier Beetle.  You can see more about the False Bombardier Beetles in the genus Galerita by checking BugGuide.

Letter 5 – False Bombardier Beetle

Is this a blister bug?
Fri, Apr 10, 2009 at 10:08 PM
Hello: I live in close proximity to the Chattahoochee River in NE Georgia. this is the second of these bugs that have made it into my house. I have not seen any in the yard, but I have not searched. 3/4 in. long, head to abdomen.
Michael
NE Georgia

Hi Michael,
This is a False Bombardier Beetle, probably Galerita bicolor. You can compare your image to photos on BugGuide. False Bombardier Beetles are predatory ground beetles and they will not harm your home bug BugGuide indicates this

“Caution: This genus has chemical defenses, see Defensive production of formic acid (80%) by a carabid beetle : Proc Natl Acad Sci U S A. 1997 June 24; 94 (13): 6792–6797. “

Letter 6 – False Bombardier Beetle

Subject: Bug id
Location: Mn
January 7, 2016, 5:34 pm
We found this bug today in our MN house. We have never seen this bug before and are wondering what it is.
Signature:?

This is a False Bombardier Beetle in the genus Galerita, and according to BugGuide:  “Adults eat other insects, especially caterpillars.”