White Spotted Sawyer Beetle Poisonous? Debunking the Myth

The white-spotted sawyer beetle may spark curiosity due to its unique appearance and potential impact on trees. While you might wonder if they pose any threat to your health, rest assured that these beetles are not poisonous to humans. They do, however, cause concerns for the health of certain trees, primarily pines.

These beetles, easily recognized by the white spot between the elytra at their base, can grow up to 1.5 inches in length and have antennae often longer than their bodies. Although they aren’t harmful to you, their affinity for pine trees and larvae feeding habits can be concerning for the overall health of these trees.

Understanding the white-spotted sawyer beetle and its potential impact on the environment can be important in protecting the trees in your vicinity. In this article, we will discuss its characteristics, feeding habits, and ways to mitigate its effect on the ecosystem.

Overview of White Spotted Sawyer Beetle

The White Spotted Sawyer Beetle, scientifically known as Monochamus scutellatus, is an insect from the genus Monochamus. It’s most commonly known as the Whitespotted Sawyer. These beetles are typically found in coniferous forests, feeding on dead or dying trees. Let’s explore some of their key features and characteristics.

As a member of the genus Monochamus, the Whitespotted Sawyer stands out with its distinctive appearance. Some of the defining features include:

  • Long antennae, usually longer than their body
  • A black and shiny exoskeleton
  • A white spot at the top center of its wing covers

It is important to mention that the Whitespotted Sawyer is not poisonous. They don’t pose a direct threat to humans or pets. However, as a wood-boring insect, they can cause damage to trees and may indirectly affect the forest ecosystem.

An interesting aspect to note is that this beetle is often confused with the invasive Asian Longhorned Beetle, which poses a significant threat to trees. To differentiate them, you can look for the distinctive white spot mentioned earlier, as the Asian Longhorned Beetle has a black spot in the same location.

In summary, the Whitespotted Sawyer Beetle is a fascinating insect with unique features. While they don’t pose a danger to humans directly, it’s essential to be aware of the potential ecological impact they might have. Additionally, knowing how to identify them is crucial to prevent confusion with invasive species like the Asian Longhorned Beetle.

Identification and Physical Features

The White Spotted Sawyer Beetle is a distinctive insect. To identify this beetle, you should pay attention to a few key features:

  • White spot: This beetle has a characteristic white spot located between the elytra at their base, which differentiates it from other sawyer beetles (source).
  • Antennae: This species is known for having very long antennae, often longer than their body. Males tend to have even longer antennae compared to females (source).
  • Wings: The Sawyer Beetle has two pairs of wings with the top pair, known as elytra, being dark and modified to serve as protective wing covers.
  • Spine & Legs: While the information on their spine is limited, the legs of these beetles are typically long and strong, adapted for gripping onto tree trunks.

Here’s a quick comparison of features to look for in the White Spotted Sawyer Beetle:

Feature Description
White spot Between elytra at their base
Antennae Very long, often longer than body itself
Wings Two pairs; top pair are dark and protective elytra
Legs & Spine Long legs; limited information on spine

Now you have a good understanding of the White Spotted Sawyer Beetle’s physical features. Keep an eye out for these unique insects during your outdoor adventures and admire their fascinating appearance. Remember that it is important not to handle these beetles, as they may be harmful to you or the beetle itself.

Life Cycle of the Beetle

The life cycle of the White-Spotted Sawyer Beetle starts with the egg stage. Female beetles lay their eggs on the bark of dead or dying conifer trees, such as pines1.

Once the eggs hatch, the larvae emerge and begin to feed on the wood beneath the bark2. These growing larvae spend their time tunneling through the wood and feeding on it, continuing to grow and molt for a couple of years3. Here’s a quick rundown of the key stages:

  • Eggs: Laid on dead or dying conifer trees by female beetles
  • Larvae: Tunnel through wood and feed on it for approximately two years

As the larvae reach the final stage of their growth, they will form a pupa inside a chamber they create within the wood4. This is the resting stage where the beetle undergoes significant changes, eventually transforming into its adult form.

Finally, the adult White-Spotted Sawyer Beetles emerge from the pupal chamber and exit the wooden tunnels they have been living in5. The adult beetles have a distinctive shiny black appearance, with a white spot between the elytra (wing covers) and long antennae6. They will then mate, lay eggs, and the cycle continues.

In summary, the White-Spotted Sawyer Beetle follows a typical life cycle consisting of egg, larva, pupa, and adult stages. They primarily inhabit and feed on dead or dying conifer trees, playing an essential role in the ecosystem by recycling nutrients from decaying wood.

Beetle’s Habitat

Distribution and Range

The white spotted sawyer beetle is widely distributed across North America. Its range extends from Alaska and the Northwestern regions, all the way to the eastern coast. These beetles are especially drawn to coniferous hosts, such as spruce forests. You can find them in both mature and recently disturbed forests, where their preferred food sources are available.

The white spotted sawyer beetles are known to seek out tree species like:

  • Pine
  • Spruce
  • Fir
  • Larch

By understanding their habitat, you can better recognize the presence of these beetles and take measures to prevent any potential damage they may cause to trees in your area. Keep in mind that while the beetles themselves are not poisonous, they can still pose a threat to the health of trees and the ecosystem as a whole.

Relation to Host Trees

White-spotted sawyer beetle, also known as Monochamus scutellatus, primarily targets conifers in the family of Pinaceae in various stages of decay. They are found in several types of trees such as:

  • Eastern white pine
  • Jack pine
  • White spruce
  • Black spruce
  • Red spruce
  • Balsam fir

Adult beetles feed on the needles of host trees, while their larvae focus on consuming the inner layers of wood. Their preference is trees that are:

  • Diseased
  • Damaged
  • Recently dead

As a friendly reminder, you should be aware that the white-spotted sawyer beetle plays a crucial ecological role by decomposing dead trees and returning nutrients to the ecosystem. This beetle is not considered to be poisonous to humans.

A key feature of the white-spotted sawyer beetle is its shiny black body adorned with a distinctive white spot between the elytra. They are often confused with the Asian longhorned beetle (ALB). While both species have a black body and long antennae, there are some differences you should be aware of:

Feature White-Spotted Sawyer Beetle Asian Longhorned Beetle
Size Smaller Larger
Body Shiny black, dull appearance Shiny black
Markings Single white spot 20 white spots
Host Softwood trees Healthy hardwoods

By understanding these differences, you can prevent confusion when identifying these different species. Enjoy observing these fascinating insects on your next nature walk!

Feeding Habits

The White-spotted Sawyer Beetle feeds primarily on the phloem and cambium layers of coniferous trees such as pine and spruce. By consuming these essential parts of the tree, the beetles play a significant role in nutrient cycling within forest ecosystems.

Although it’s common to wonder if the White-spotted Sawyer Beetle is poisonous, there isn’t evidence to suggest that they’re harmful to humans. They are, however, capable of causing damage to trees, especially those that are already stressed or diseased.

Some key aspects of their feeding habits include:

  • Preference for weakened or dying coniferous trees
  • Consumption of phloem and cambium layers, which are essential for tree survival and growth
  • Impact on nutrient cycling in forest ecosystems

When it comes to the White-spotted Sawyer Beetle, it’s essential to focus on their impacts on trees and forest health, rather than any potential harm to humans. By understanding their feeding habits and significance in nature, you can better appreciate the ecological role these beetles play in our environment.

Beetle as a Pest

The White-Spotted Sawyer beetle is mainly a minor pest of coniferous trees such as white pine, balsam fir, and species of spruce. This wood-boring insect prefers damaged, diseased, or weakened trees for infestation.

When compared to the invasive Asian longhorned beetle, the White-Spotted Sawyer beetle appears duller and slightly smaller. Additionally, it has a distinctive white spot between its wing covers that distinguishes it from the Asian longhorned beetle.

As a secondary pest, the damage caused by the White-Spotted Sawyer beetles is limited. Adult beetles might feed on the bark of the undersides of twigs, causing minor harm. However, these beetles are native to regions such as the Northeast and Northwest of the United States, and as far as Alaska.

In your garden or forest, be mindful of the White-Spotted Sawyer beetle infestation. Regularly monitor the health of your trees and promptly remove any dying or weakened ones. Such actions will help mitigate the potential damage caused by these beetles and prevent their spread to healthy trees.

Remember to keep a friendly and watchful eye on your trees, as prevention is better than dealing with an infestation of this wood-boring insect.

Comparison with Other Beetles

In this section, we’ll compare the white spotted sawyer beetle with other related beetles, including the spruce sawyer, alb, Asian longhorned beetle, longhorn beetle, and spruce bug.

White Spotted Sawyer Beetle vs. Spruce Sawyer

The white spotted sawyer beetle and the spruce sawyer are both longhorned beetles. However, the white spotted sawyer beetle has a white spot between the elytra at their base, while the spruce sawyer lacks this feature. Both species have long antennae, with the male’s being longer than the female’s.

White Spotted Sawyer Beetle vs. Asian Longhorned Beetle (ALB)

While the white spotted sawyer beetle and the ALB are both longhorned beetles, they have some distinguishing features:

  • The ALB has black and white banded antennae, while the white spotted sawyer beetle has uniformly colored antennae.
  • The ALB has several white spots on the body, while the white spotted sawyer beetle has one distinctive white spot.

White Spotted Sawyer Beetle vs. Longhorn Beetle

Longhorn beetle is a generic term for all beetles within the Cerambycidae family, which includes both the white spotted sawyer beetle and the ALB. Since both of these beetles are a part of the longhorn beetle family, they share many similarities, such as long antennae.

White Spotted Sawyer Beetle vs. Spruce Bug

The spruce bug is not a beetle but actually a true bug belonging to the family Miridae. You can differentiate between the two by their mouthparts: beetles have chewing mouthparts while true bugs have piercing-sucking ones. Spruce bugs are also generally smaller and lack the distinctive long antennae found in longhorned beetles.

In conclusion, the white spotted sawyer beetle shares some similarities with other longhorned beetles, but differs considerably from the spruce bug. It is important to know their distinctions for proper identification and pest management.

Defense Mechanisms and Predators

You might be curious about the defense mechanisms of the white-spotted sawyer beetle and its predators. These beetles, like other insects, have evolved various strategies to protect themselves from threats, such as fire and other predators.

For example, the sawyer beetle might protect itself by releasing chemicals when threatened. These chemicals, produced either constitutively or in response to damage, can affect the feeding, growth, and survival of various predators, as observed in other plant defense mechanisms against insect herbivores.

As for the role of fire in their ecology, it is known that certain beetles can withstand and even thrive in post-fire environments. While it is not specifically mentioned for the white-spotted sawyer beetle, other species may serve as examples.

Now, let’s discuss some of the predators that might hunt the sawyer beetle. Predators can include birds, small mammals, and even some other insects. An interesting example is a group of predatory wasps, which are known for hunting various insect pests. Some species of solitary wasps would only sting to capture prey, thereby acting as effective predators of insects, including beetles.

In conclusion, the defense mechanisms of the white-spotted sawyer beetle and their relationships with fire and predators play a role in the fascinating ecology of these insects.

Reporting and Identification Tools

When you come across a white-spotted sawyer beetle, it’s important to have the proper tools and resources for accurate identification. Here are some helpful tools and guides:

The US Forest Service provides a PDF management guide for sawyer beetles that can help you identify and distinguish them from other species. Key characteristics to look for include:

  • Shiny black color
  • White spot between the elytra at their base
  • Very long antennae, often longer than their body

You can also consult BugGuide, a community-driven platform that brings together experts, editors, and licensed content to provide identification assistance. BugGuide is an excellent resource for:

  • Comparing images of white-spotted sawyer beetles and other similar insects
  • Receiving input from knowledgeable editors in the field
  • Checking for updates on taxonomy and distribution

Another useful tool is the Free mobile apps, provided by the United States Department of Agriculture (USDA) APHIS. Although these apps are primarily designed for citrus insect pests, they can serve as a helpful reference when examining a potential white-spotted sawyer beetle.

In summary, when trying to identify a white-spotted sawyer beetle, always use reliable resources and tools such as the US Forest Service guide, BugGuide, and USDA mobile apps. This will ensure that you correctly identify the beetle and avoid confusion with other species.

Footnotes

  1. https://florence.extension.wisc.edu/white-spotted-sawyer-beetle/

  2. https://www.fs.usda.gov/Internet/FSE_DOCUMENTS/stelprdb5187547.pdf

  3. https://extension.umaine.edu/home-and-garden-ipm/fact-sheets/common-name-listing/sawyer-beetles/

  4. https://www.canr.msu.edu/ipm/diseases/may-or-june-beetle

  5. https://content.ces.ncsu.edu/southern-pine-sawyer

  6. https://florence.extension.wisc.edu/white-spotted-sawyer-beetle/

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 – Sawyer Beetle

 

what’s this?
June 9, 2010
Live Oak, Florida
He’s pretty kool… What is it?
Can’t seem to find him anywhere!
DogBagAndMore.com
Live Oak, Fl

Sawyer Beetle

Dear DogBagAndMore,
This is one of the Sawyer Beetles in the genus Monochamus, but your head on view is not ideal for species identification.  You may read more about the genus on BugGuide.
We will be setting your letter to post while we are out of the office next week so that our readership can enjoy daily updates to our website.

Letter 2 – Pine Sawyer

 

Hello, this bug was found boring through the plaster in my wall last night. What kind of bug is this? It left a hole about .25″ in diameter. I just moved into a newly constructed home in a newly constructed community last week. I live in Modesto CA, which is in the Central Valley and it is an agricultural area. It is possible this bug may not be from this area at all. It may have come along with the building materials the builders used. Can you tell from this picture what type of bug this is and if it is male or female. I am kind of concerned about whether or not this bug could of laid eggs inside my wall. If you need other pictures I will try and take some better ones. This one that I took is through a plastic zip-lock bag that I have the bug in. Also, the white powdery stuff on the bug is probaly the plaster from the wall.
Thanks so much !
Chris

Dear Chris,
It looks to me like you have a Pine Sawyer, probably Monochamus titillator. Members of this genus are usually over an inch in length. The first antennal segment has a scarlike area near the tip. The antennae of the males are sometimes twice as long as the body, while females have antennae about as long as the body. Your specimen looks like a female. They feed on evergreens, usually on freshly cut logs but they may sometimes attack living trees. They also bore into felled trees where the female lays eggs. I’m guessing your specimen has been boring in the pine of your home since the tree was cut. You really don’t need to worry about being infested at this point. Sometimes adults may emerge years after the eggs were laid.

Letter 3 – Pine Sawyer

 

what is it …
and why did it fly into my kitchen window at dusk? It looks like some cockroaches I saw in Baja many years ago, but I’ve never seen anything this big here just south of San Francisco.
Thank you.
Lynn

Hi Lynn,
You have been visited by a Pine Sawyer, Ergates spiculatus, also known as the Spineed-Neck Longhorn. Larvae eat the sapwood and heartwood of pines and Douglas firs and adults emerge July – August. I guess the rains brought them out a little early this year. Females are often attracted to lights. Their habitat is usually forests near and above 4000 feet. According to Hogue: “campers in pine flats in neighboring mountains are frequently startled when these beetles loudly buzz into their lanterns on warm summer evenings.”

Letter 4 – Possibly Southern Pine Sawyer

 

Laughing Brown Beetle
September 8, 2009
This brown beetle is speckled white and makes a laughing sound while bobbing its head if provoked. All the images are of the same bug. IT doesn’t seem to move around much. I left it on my desk and it was still in the same spot when I came back about 45 minutes later. The antennae are about as long as the body and it rotates them in opposite circles from time to time. The legs end in hook-like “feet” and it is capable of clinging to things very well. Has no problem hanging upside down. Has two ant-like mandibles jutting downward from the base of the head. The white spots on the back appear to be arranged into loose chevrons pointing towards the posterior, there are three in all. There are two symmetric orange/tan spots on the back of the head. Antennae are ro ughly 1.5in in length. Body appox. 7/8th of an inch long 1/4in wide. Head is narrower then the body and about 1/3 of the total length.
Hissing Harry
Lexington, Virginia, USA

Possibly Southern Pine Sawyer
Possibly Southern Pine Sawyer

Dear Hissing Harry,
Your photos lack clarity, but we believe this is one of the Pine Sawyers in the genus Monochamus, possibly the Southern Pine Sawyer, Monochamus titillator.  You can compare your individual to images posted to BugGuide.

Possibly Southern Pine Sawyer
Possibly Southern Pine Sawyer

Letter 5 – Sawyer

 

Monochamus carolinensis?
Location:  Madera County, California
September 24, 2010 11:26 pm
This awesome beetle flew into my chest today (9/24/2010), bounced off and into my camera bag. Luckily, I already had the camera out. I believe this to be Monochamus carolinensis but I am unable so far to determine the range of this beetle in any of the books we have nor on the internet.
Note: The beetle was encouraged to climb onto a feather I found nearby when it came time to close up the camera bag sans beetle.
We live in Raymond, California (Madera County) at around 1100 feet elevation. The terrain is oak savanna, with a good population of gray pine.
Signature:  Megan Ralph

Sawyer

Hi Megan,
While we believe you are correct that this is a Sawyer in the genus
Monochamus, we do not believe it to be Monochamus carolinensis.  Rather, we believe it may be Monochamus obtusus, a species represented on BugGuide from a single sighting in Oregon.

Thank you so much for the reply!  The link you provided does look a lot more like the individual I saw.  I sure appreciate your help and great web site.
Megan

Letter 6 – Sawyer

 

Subject: Saved from drowning in cats’ water bowl… what is it?
Location: Orange, VA near Lake Orange
May 31, 2013 6:57 am
Found this morning lying still in pet water dish, May 31, 2013. After drying out on deck rail, it came to life, crawling on my arm. Segmented, very long antennae. Front legs look webbed or clubbed on feet. Has tiny ”hairs” enabling it to stick to anything. Kind of grasshopper like or beetle. Can you tell from my photo what it might be. Location: Orange, VA, piedmont area of central VA. Love your website!
Signature: Janine E

Sawyer
Sawyer

Hi Janine,
This is one of the Sawyers in the genus
Monochamus, and the especially long antennae is an indication this is a male.  Sawyers are Longhorned Borer Beetles in the family Cerambycidae.  There is not enough detail in your photo to be certain of the species, but you can browse through BugGuide to try to determine the most likely species.

Thank you, Mr. Marlos, for identifying the bug I found. I will enjoy reading up on the Sawyer or Longhorned Borer Beetles. Could be we have them on our pine trees that were damaged by storms this and last year.
Your quick and timely response is greatly appreciated.
Janine

P.S.  We also tagged you as a Bug Humanitarian.

Thank you. Believe it or not, I am kind to spiders and stink bugs too. When I find them in my house, I catch them and put them outdoors. Insects are interesting critters. My father taught me to appreciate nature, and had a book by Jean-Henri Fabre, a French entomologist and author, that I really enjoyed.

Letter 7 – Sawyer, but which species???

 

Subject: What is it?
Location: Bartlett, TN (Memphis)
June 22, 2013 6:58 am
Hello, I live in Memphis, TN. Recently, we have found two of these creatures in our house. They do not fly. They really don’t move much at all. Their antennae are extrememly long – maybe three times as long as their body. Their body is about an inch long. It has little pincher things on it’s face. Body is brown, speckled – blends in perfectly on a pebbled sidewalk.
I have searched google for a match, but have been unable to find one. We have never seen one of these before now.
Thank you very much!
Signature: Vera Sidhom

Sawyer
Sawyer

Dear Vera,
This is a Longhorned Borer Beetle in the family Cerambycidae, and we believe it is one of the Sawyers in the genus
Monochamus, though we are reluctant to attempt a species identification.  According to BugGuide:  “Either black or mottled gray. First antennal segment has a scar-like area near the tip. Antennae of the male is twice as long as the body, about as long as the body in females.”  The length of the antennae indicates your individual is a male.

Sawyer
Sawyer

Wow!  That was fast!  Thank you so much for your help – we had never seen this bug before and suddenly we had three of them move in with us.  Glad to know what they are.
Thank you again,
Vera

 

Letter 8 – Sawyer perhaps

 


This guy is about 1 1/4" long in the body about 10" wide antennae span (right off the camera lens here. We live in Northern New Mexico and found him in our door frame just last week. He let me move him onto this leather and relocate him without a fuss. WTB?
Kim

Hi Kim,
Wow!!! What antennae. We are relatively certain this is one of the Sawyers in the genus Monochamus, but we would like to check with Eric Eaton for confirmation.

Update from Eric Eaton (06/22/2006):
“Ok, the top longhorned beetle, with the REALLY long antennae, is probably something in the genus Acanthocinus.”

Letter 9 – Sawyer with PHoretic Mites

 

Subject: Big Ugly Bug
Location: Central to Easter Ohio, very warm bedroom
June 26, 2013 10:41 am
I was wondering if you could identify a beetle like bug for me.
It is very beetle like. It has antennae that are at least twice as long as it’s body. 6 legs. When I poke at it, it does not fly. Not flat like a cockroach. Grayish to brown. Very slow moving. About an inch to 2 inches long.
Thank you in advance!
Signature: Shawna Arthur

Sawyer with Phoretic Mites
Sawyer with Phoretic Mites

Dear Shawna,
This is a Sawyer in the genus
Monochamus, and we think he is rather beautiful.  Male Sawyers like most other Longhorned Borer Beetles in the family Cerambycidae have antennae considerably longer than the females of the species.  Take a close look at his thorax.  Those are Phoretic Mites which hitchhike on the Sawyer, using the beetle’s ability to fly to transport them to a new location and hopefully a more plentiful food supply.  See BugGuide for additional information on Sawyers in the genus Monochamus.

Authors

    by
  • 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.

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4 thoughts on “White Spotted Sawyer Beetle Poisonous? Debunking the Myth”

  1. I live in Las Vegas and we’ve been besieged by Pine Sawyer beetles after a heavy rain last week. They are huge! There are pine trees in the neighborhood, so I guess they came from them. Creepy but fascinating!

    Reply
  2. I saw one of the beetles emerging from the ground, so I believe we indeed have palo verde root borers. Thank you!

    Reply

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