Spined Oak Borer: Do They Bite and What to Know

Spined oak borers are insects that can cause concern for many who encounter them. You might wonder if these creatures pose any threat to you or your loved ones. It’s important to know that spined oak borers are not known for biting humans or causing any harm to people. Let’s explore this topic further.

These beetles are primarily focused on feeding and reproducing, so they have little interest in interacting with humans. Their main targets are actually oak trees, where they lay their eggs and feed on tree tissues. While the spined oak borer itself may not be directly harmful to you, it can still have a negative impact on oak trees, which can affect your yard or property if you have oak trees present.

Now that you have a basic understanding of spined oak borers and their behavior, you can better appreciate their presence in nature and the ecological role they play. Remember, these insects aren’t out to bite you, but it’s still worth learning about them to protect your trees and preserve the beauty of your outdoor space.

The Spined Oak Borer

The Spined Oak Borer, scientifically known as Elaphidion mucronatum, is a species of long-horned beetle. These insects are often found on oak trees, where the larvae feed on the wood.

  • Appearance: Adult Spined Oak Borers have a striking appearance, with long antennae and slender bodies. Their color ranges from reddish-brown to black, and they have distinctive spine-like projections on their thorax.
  • Larvae: The larvae of these beetles are cream-colored, featuring a segmented body and lack of legs. They bore into the wood of oak trees, causing damage as they feed.

As you might have guessed from their name, the Spined Oak Borer is primarily associated with oak trees. When adult females lay their eggs on the bark of the tree, the hatched larvae then burrow into the wood. While these beetles can cause damage to the trees they infest, they generally do not bite or pose a threat to humans.

Some key characteristics of the Spined Oak Borer:

  • Feeding habits: Feeds on oak trees throughout different stages of their lives.
  • Habitat: Mainly found in forested areas where oak trees are abundant.
  • Size: Adult Spined Oak Borers can reach up to 0.5 inches (12mm) in length.

In conclusion, the Spined Oak Borer is a fascinating member of the long-horned beetles family, known for its association with oak trees and its distinct physical appearance. While they do not bite humans, their larvae can cause damage to oak trees by feeding on the wood.

Do Spined Oak Borers Bite?

If you’re wondering whether spined oak borers bite, rest assured, they typically are not known to bite humans or pets. Spined oak borers are wood-boring beetles, and their primary focus is feeding on oak trees, not people or animals. The larvae, or young borers, bore tunnels under the bark of oak trees, leading to tree damage or even death.

However, since spined oak borers have mandibles (jaws) to chew through wood, it’s possible that they could pinch you if they were handled improperly. But, they will not actively seek out to bite or harm you.

  • Features of spined oak borers:
    • Focus on oak trees
    • Larvae bore tunnels beneath the bark
    • Can cause tree damage or death

While their potential to cause harm to humans is quite low, it’s still important to handle spined oak borers with care, as they may become distressed in captivity. If you come across one or suspect an infestation in your oak trees, it’s advised to consult a professional arborist or pest control specialist to manage the situation.

In summary, you don’t have to worry about spined oak borers biting you or your pets. Their primary target is oak trees, and while they can cause significant damage to trees, they pose little threat to humans and animals.

Habitat and Hosts

The spined oak borer is an insect that typically targets oak trees, both healthy and stressed ones. They can also affect other types of trees, shrubs, and plants, but oaks are their main host.

These borers are more likely to infest trees that are already stressed or weakened by factors such as drought, disease, or poor nutrition. To protect your trees from these pests, it’s crucial to maintain their health by cultivating, fertilizing, and watering them as needed.

Now, regarding your question about whether spined oak borers bite, these insects don’t pose a direct threat to humans, as they primarily feed on wood and tree tissues. Their larvae bore into the tree’s bark, creating tunnels and potentially causing damage to the tree’s vascular system. Adult spined oak borers are harmless to humans and would not bite.

Keep in mind the importance of:

  • Monitoring your trees for signs of infestations
  • Properly maintaining your trees to reduce their vulnerability
  • Consulting with a professional arborist or entomologist if you’re unsure about your trees’ health

By staying vigilant and proactive in your tree care, you can help reduce the risk of spined oak borer infestations and preserve the beauty and vitality of your trees. Happy tree-keeping!

Life Cycle

The life cycle of the spined oak borer consists of several stages: eggs, larvae, and adults. Let’s explore each of these stages in detail.

Eggs: Female spined oak borers lay their eggs on the bark of oak trees, usually in areas where the bark is thin or cracked. The eggs are tiny, so you may not even notice them if you’re not paying close attention. After being laid, the eggs begin to develop and eventually hatch into larvae.

Larvae: Once the eggs hatch, the larvae start feeding on the wood beneath the bark. As they feed, they create tunnels (also known as galleries) in the wood. These tunnels can eventually cause structural damage to the tree, so it’s essential to keep an eye out for any signs of infestation. The larvae stage typically lasts for 1-3 years, during which time they grow and continue to feed on the wood.

Adults: After completing their development, the larvae pupate within their tunnels. They enter the pupal stage briefly before they emerge as adults. Adult spined oak borers are often seen flying around oak trees in search of a mate and a new tree to infest. They don’t have a long lifespan, but they can cause significant damage during their short time as adults.

You might be wondering if the spined oak borers bite humans. Fortunately, they do not bite or pose any direct threat to humans. However, they can cause severe damage to oak trees, which may be a concern for homeowners and forest managers.

Keep an eye out for telltale signs of infestation, such as holes in the bark where adults have emerged, or the presence of sawdust-like frass around the base of the tree. If you suspect a spined oak borer infestation, it’s best to consult with a professional to assess the situation and determine the best course of action to protect your oak trees.

Damage Signs

When dealing with spined oak borers, it’s essential to know how to spot the signs of damage in your oak trees. In this section, we’ll cover some key indicators to help you recognize an infestation.

Holes in the Bark
One common sign of spined oak borer presence is small, round exit holes in the tree’s bark. These holes are typically about the diameter of a pencil lead. Pay close attention to the main trunk and major limbs, as this is where the borers usually reside.

Signs of Damage
In addition to exit holes, you may also notice the tree appears stressed or in poor health. Infested trees may show signs such as wilting leaves, leaf loss, and overall decline in growth and vigor. The damage caused by borers can weaken the tree’s structure, making it more susceptible to external factors and other diseases.

Exit Holes
Once the spined oak borer larvae mature, they will chew their way out of the tree, creating the exit holes mentioned earlier. These holes are not only a clear sign of infestation but also indicate that the borers have likely transitioned from larvae to adult beetles. This may signal that the infestation has been ongoing for an extended period.

Stressed Trees
Spined oak borers are more likely to attack weak or damaged trees, as they are generally attracted to trees that are already in a weakened state. Factors such as crowding, stem and trunk diseases, and other insect damage can contribute to a tree’s vulnerability.

To sum up, keep an eye out for holes in the bark, signs of overall tree stress, and evidence of exit holes to identify and address a spined oak borer infestation in your oak trees. By catching the problem early and taking appropriate action, you can help protect your trees from further damage.

How to Control

Spined Oak Borer Control

Spined oak borers can cause significant damage to oak trees. Fortunately, there are several methods to control these pests. A good starting point is to ensure the health of your oak trees, which makes them less attractive to borers.

One way to maintain tree health is by properly mowing your lawn. Using a lawn mower can help prevent damage to the tree’s roots, which can lead to stress and increased vulnerability to borers.

Chemical Sprays

Chemical sprays are a popular method for controlling spined oak borers. Some effective sprays include insecticides containing permethrin, carbaryl, or bifenthrin. Always follow the label instructions for mixing and application rates. Timing is crucial, as the best time to apply insecticides is when the adult borers are active, typically in late spring or early summer.

Here are some pros and cons of using chemical sprays:


  • Effective at controlling spined oak borers
  • Can prevent further damage to trees


  • May harm non-target insects
  • Can have adverse effects on the environment

Alternative Methods

If you’re looking for alternative control methods, some options include:

  • Removing and destroying infested branches or trees
  • Encouraging natural predators, such as woodpeckers, by providing suitable habitat
  • Ensuring proper tree care and maintenance to reduce stress on trees

Remember, a healthy tree is your best defense against spined oak borers.

What Eats Spined Oak Borers

When it comes to spined oak borers, various predators find them to be a suitable meal. These predators help keep the spined oak borer population in check, providing natural pest control.

Animals: Some mammals, like bats and rodents, might snack on spined oak borers when they come across them. Bats are particularly skilled at catching flying insects, including borers that may be active during dusk or night time.

Birds: Woodpeckers, for example, are known to feed on wood-boring larvae such as the spined oak borer. Other birds that may consume the borers include nuthatches and chickadees, as they forage for insects on tree bark as well.

Fishes: Although less likely, there is a possibility that fish may consume spined oak borers, especially if borer-infested wood falls into water bodies, exposing the insects to fish like sunfish and bass.

Mites: Predatory mites can also contribute to controlling spined oak borer populations. Mites may feed on the eggs or young larvae of these wood-boring insects.

In summary, spined oak borers face predation from various sources, including mammals like bats and rodents, birds such as woodpeckers, nuthatches, and chickadees, as well as predatory mites. These predators play a vital role in maintaining a balanced ecosystem and reducing the spined oak borer’s impact on oak trees.

Similar Species

The Spined Oak Borer is just one of many wood-boring insects that can cause damage to trees. In this section, we’ll briefly discuss some similar species that may also be of interest:

Bark Beetles are small insects that can infest and damage various species of trees, including evergreens and spruce trees. Bark beetles create holes as thick as pencil lead along the trunk and major limbs, which can lead to tree decline.

Metallic Wood Borers, also known as Buprestidae, are a large family of beetles. They can have a shiny and metallic appearance, which makes them quite distinctive. Among them, the Bronze Birch Borer and the Flatheaded Appletree Borer are notable examples.

  • The Bronze Birch Borer primarily infects birch trees, causing branches to die and potentially killing the entire tree.
  • The Flatheaded Appletree Borer attacks a variety of trees, including apple, oak, and maple. It creates tunnels under the bark, disrupting the flow of sap and potentially killing branches or entire trees.

The Locust Borer and Red Oak Borer are both Round-Headed Borers that can also cause damage to tree species.

  • The Locust Borer typically infests black locust trees, weakening the wood and sometimes causing the tree to break during strong winds.
  • The Red Oak Borer is native to the eastern United States and primarily infests red oak trees, causing weakening of the wood and potential tree mortality.

Finally, the Twig Girdler is a type of longhorn beetle that girdles twigs on a variety of tree species, including oak, elm, and hickory. Twig girdlers cut circular grooves into twigs, causing them to fall off the tree.

Species Primary Hosts Damage
Bark Beetles Evergreens, spruce Holes, tree decline
Bronze Birch Borer Birch Branch death, tree mortality
Flatheaded Appletree Borer Apple, oak, maple Tunneling, branch/tree death
Locust Borer Black locust Weakened wood, breakage
Red Oak Borer Red oak Weakened wood, tree mortality
Twig Girdler Oak, elm, hickory Twigs falling off the tree

It’s essential to identify the specific borer species when dealing with an infestation, as management strategies may vary depending on the insect. Identification can be challenging, but understanding the differences between these pests can help you better protect your trees and maintain their health.

Family and Orders

The spined oak borer belongs to the family Cerambycidae, which consists of longhorn beetles. Here are some characteristics of the family Cerambycidae:

  • Cerambycidae: Long antennae,often longer than their bodies
  • Diverse in size and shape, usually cylindrical

Within this family, you’ll find several subfamilies, including Cerambycinae. Let’s take a closer look at some differences between these subfamilies:

Subfamily Description Example
Cerambycinae Beetles with flat and short antennae Spined oak borer
Lamiinae Beetles with clubbed or thickened antennae White-spotted sawyer
Sphaerioninae Small, round beetles with noticeable tough exoskeleton Metallic wood-boring beetle

Although not within the spined oak borer’s family Cerambycidae, weevils are another group of beetles that can damage trees. They belong to the superfamily Curculionoidea and possess a snout-like structure called a rostrum. If you ever come across a beetle with a snout, it’s likely a weevil.

In regards to your concern about spined oak borers biting, these beetles are not known for biting humans. They mainly feed on oak trees and are not considered harmful to people.

Remember, when dealing with these beetles:

  • Spined oak borers are from the Cerambycidae family
  • Weevils have a snout-like structure and damage trees too, but belong to a different superfamily

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 – Spined Oak Borer sighted during Eclipse


Subject: Eclipse 2017
Location: Farmington, CT USA
August 21, 2017 1:00 pm
While we were busy going in and out of the door at work watching the eclipse through our approved pinhole box, this fellow decided to apply for a job. We decided he didn’t quite fit the position and showed him the way out, but not before taking his beauty shot. For further reference, could you please tell us what he is/was? Two inches long, with antenna stretching almost 5 inches tip to tip! Amazing creature.
Signature: Otto Katz

Spined Oak Borer

Dear Otto,
Your eclipse visitor appears to be a Spined Oak Borer,
Elaphidion mucronatum, which we identified using Arthur V. Evans book Beetles of Eastern North America, where it states:  “Antennae extend past tips of elytra (male) or not (female)” and “Larvae develop in dead branches of deciduous trees and shrubs, also bald cypress.”  We verified that identification with this BugGuide image, and BugGuide states:  “Extremely polyphagous; hosts include most eastern hardwoods & shrubs.”  The extreme length of the antennae on your individual indicates it is a male.

Letter 2 – Spined Oak Borer, we believe


Subject:  What big is this?
Geographic location of the bug:  Long Island,  NY
Date: 07/05/2018
Time: 03:22 PM EDT
Your letter to the bugman:  This wad on the outside for of my apartment building.
How you want your letter signed:  Richard Feltman

Spined Oak Borer, we believe

Dear Richard,
Though the critical detail in your image is not ideal, the prominent spines at the ends of the elytra or wing covers are relatively unique, which is why we believe this is a Spined Oak Borer,
Elaphidion mucronatum, a species pictured on BugGuide.


  • 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.

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    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.

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