White spotted sawyer beetles are fascinating insects that you might encounter in forests and wooded areas. These beetles are characterized by their black body, white spot on the base of their elytra (wing coverings), and remarkably long antennae, which are often longer than their body. As a part of the longhorn beetle family, these beetles play a crucial role in the ecosystem.
What white spotted sawyer beetles eat mainly revolves around their life stage. During their larval stage, these beetles have a voracious appetite for the wood of coniferous trees, particularly those that are dead, weak, or have been recently damaged by fires or storms. As adults, they feed on the bark, cambium, and even the foliage of trees. In doing so, they contribute to the natural breakdown and recycling of nutrients in the forest.
It’s important to note that while white spotted sawyer beetles are an essential part of the ecosystem, they can sometimes be detrimental to the health of trees if their population increases dramatically or if they feed on healthy trees. Understanding their feeding habits and life cycle can ultimately help in managing their populations and protecting our forests.
White Spotted Sawyer Beetles: An Overview
White Spotted Sawyer Beetles, scientifically known as Monochamus scutellatus, belong to the class Insecta within the phylum Arthropoda and kingdom Animalia. These beetles are native to the Northeast and Northwest regions of North America, including Alaska.
As an adult insect, the White-Spotted Sawyer Beetle grows up to 1.5-2.7 cm long and has a distinctive white spot at the base of their wings. Their dark-colored, shiny body is adorned with white spots and mottling. These beetles are often mistaken for the notorious Asian Longhorned Beetle (ALB), although they have differences:
- White Spot: Single white spot on White-Spotted Sawyer, while ALB has about 20 white spots on each wing cover
- Size: White-Spotted Sawyer is slightly smaller than ALB
- Host Trees: White-Spotted Sawyer attacks softwood trees, while ALB targets healthy hardwoods
The adult beetles are known for their long antennae, with the males having longer antennae than the females. These insects play a significant role as decomposers of dead and dying wood in their host trees, which typically include Douglas-fir, true fir, spruce, and pine.
To keep your friendly tone, focus on the positive aspects of these insects and how they contribute to the overall ecosystem. Provide examples of ways they help to maintain the health of the forest and how people can differentiate them from more damaging beetles like the ALB. Offer tips on what to do if someone encounters a White-Spotted Sawyer Beetle and emphasize the importance of understanding and respecting the natural world around us.
Color and Body Patterns
Adult white-spotted sawyer beetles have a shiny black body with distinctive white spots on their wing covers (elytra). Males and females display similar color patterns; however, males typically have longer antennae than females. These beetles are around 1.5-2.7 cm in length, making them easily noticeable when resting on tree trunks or branches.
Some features of white-spotted sawyer beetles include:
- Shiny black body
- White spots on wing covers
- Body length of 1.5-2.7 cm
The most distinguishing feature of the white-spotted sawyer beetle is the single white spot located between the elytra at their base near the thorax. This white dot sets them apart from other species, such as the Asian longhorned beetle, which has around 20 white spots per wing cover and a focus on attacking hardwood trees.
A brief comparison of white-spotted sawyer beetles and Asian longhorned beetles:
|White-Spotted Sawyer Beetle
|Asian Longhorned Beetle
|Shiny black with white spots
|Shiny black with white spots
|Single white spot near thorax
|20 white spots on each wing cover
|Hardwood trees, especially maple
|Males have longer antennae than females
|Antennae length similar for males and females
By recognizing the unique characteristics of the white-spotted sawyer beetle, you can better understand their role in the ecosystem and avoid mistaking them for other, potentially harmful species.
Habitat and Geographic Range
White-spotted sawyer beetles can be found in North America, particularly in regions such as Canada, Alaska, and Oregon. These beetles thrive in boreal forests where they inhabit coniferous trees, including pine, spruce, and fir1. In Mexico, you might find them in regions with similar tree types.
Their diet consists of wood, specifically the cambium layer of dead or dying conifer trees2. As larvae, they bore into the wood and feed on it, which aids in the decomposition process. This makes them beneficial insects in their native habitats.
White-spotted sawyer beetles are often mistaken for the invasive Asian longhorned beetle3. However, the main difference between the two is the presence of a distinct white spot behind the head and 20 white spots on each wing cover in the white-spotted sawyer beetle.
- White-spotted sawyer beetles are native to North America, including Canada, Alaska, and Oregon.
- They inhabit boreal forests and feed on dead or dying conifer trees.
Diet of White Spotted Sawyer Beetles
White spotted sawyer beetles mainly consume conifer trees, such as pines, spruces, and firs. They have a particular preference for:
- Eastern white pine
- Black spruce
- Pine trees
These beetles target dead or dying trees, as well as branches of healthy conifers. Occasionally, they may also feed on maple trees.
The larvae of white spotted sawyer beetles play a significant role in their feeding habits. The larva burrows into the phloem and cambium layers of conifer trees. Here’s a brief overview of how they feed:
- Adult beetles lay eggs in the bark of suitable trees.
- The eggs hatch into larvae.
- The larvae feed on the tree’s phloem and cambium layers, which provide essential nutrients.
- Eventually, the larvae pupate, and new adult beetles emerge to continue the cycle.
When feeding, these beetles help break down dead or dying trees, playing a crucial role in the forest ecosystem. Their consumption of conifer tree parts allows for the decomposition of those tree materials and nourishes the surrounding environment. However, they can cause damage to trees if they infest them in large numbers.
Lifecycle and Reproduction
White spotted sawyer beetles (Monochamus notatus) engage in a unique mating process. The males locate potential mates by detecting pheromones emitted by females. Once a male finds a female, he approaches her and touches her antennae, signaling his intention to mate. After a successful mating, the female beetle is ready to lay eggs.
The lifecycle of white spotted sawyer beetles undergoes several stages, involving eggs, larvae, pupae, and adults:
- Eggs: The female beetle lays her eggs individually or in small groups, usually in the bark or crevices of weakened or dead trees. This provides a safe environment for the eggs to develop and hatch.
- Larvae: After hatching, the larvae begin feeding on wood as they tunnel through it, this process often leads to infestations in trees. The larval stage can last from a few months to over a year, depending on environmental conditions.
- Pupae: When the larvae are fully grown, they form a pupal chamber in the wood and enter the pupal stage. Here, they undergo metamorphosis, eventually transforming from larvae to adult beetles. This stage typically lasts a few weeks.
- Adults: Fully formed adult beetles emerge from the pupal chamber and exit the tree in search of a mate. Adult males and females search for suitable partners to continue the reproduction process and perpetuate their life cycle.
By understanding the lifecycle and reproduction process of white spotted sawyer beetles, you can better prevent potential infestations and protect your trees from damage. Always keep an eye out for any signs of their presence, and take appropriate action to manage their population in your surroundings.
White Spotted Sawyer Beetles and Their Environment
Role in Ecosystem
White spotted sawyer beetles play a role in the ecosystem where they primarily feed on damaged or weakened coniferous trees like pines and spruces. These beetles tunnel into the wood, eventually laying their eggs in these tunnels. This helps break down the damaged trees, allowing nutrients to be returned to the soil. On the other hand, healthy trees are less likely to be attacked by these beetles, as they have a preferred host of diseased or weakened trees1.
Impact on Logging Industry
The logging industry needs to be aware of the presence of white spotted sawyer beetles as they can create complications when infesting valuable pine timber. Here’s a comparison of the impact white spotted sawyer beetles have on the logging industry compared to other insects:
|Impact on Logging Industry
|White Spotted Sawyer Beetle
|Prefer weakened trees, can infest valuable timber
|Attack and weaken healthy trees, cause more damage
|Asian Longhorned Beetle (ALB)
|Attack healthy hardwoods, high risk to forests
While the larvae of white spotted sawyer beetles create tunnels within the infested logs, their impact on the logging industry remains less severe compared to bark beetles or the invasive Asian longhorned beetle2.
Interactions with Other Insects
In addition to their role in the ecosystem and the logging industry, white spotted sawyer beetles interact with other insects. They have a relationship with certain fungi, as the fungi aid in the decomposition of weakened trees that these beetles infest3.
Furthermore, white spotted sawyer beetles often compete with bark beetles. Bark beetles typically attack healthy trees, weakening them and creating an opportunity for sawyer beetles to colonize these now-weakened trees. Sometimes, bark beetles end up being the prey of long-horned beetle predators, which can control bark beetle populations in the ecosystem4.
Behaviour and Adaptations
The whitespotted sawyer beetle (Monochamus scutellatus) is a species of longhorn beetle that has adapted to thrive in fire-affected forests. They are particularly attracted to burned trees, where they find suitable conditions for oviposition and larval development. The adults utilize fire-weakened trees by laying their eggs in the soft bark or twig bark, creating oviposition holes for their offspring.
- Adult beetles are attracted to burned areas
- Oviposition holes are made on weakened trees
- Larvae develop in fire-affected environments
Communication and Pheromones
These beetles are known to use chemical communication in the form of pheromones and kairomones for various purposes. Pheromones are used by females to attract mates, and by males to locate potential mates. In addition, they use kairomones, which are chemical cues emitted by their host plants, to locate suitable oviposition sites.
- Pheromones for mating communication
- Kairomones for locating oviposition sites
The whitespotted sawyer demonstrates its adaptations to its environment through selective behavior towards fire-damaged trees and chemical communication methods. By understanding these behaviors, you can better appreciate the versatility and resilience of this unique beetle species found across the northeastern United States and other regions.
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 – White Spotted Rose Beetle from Spain
Subject: what is this bug?
Location: 40.5 North 0.5 East
April 10, 2014 4:49 am
I live in rural Catalunya, NE Spain, not far from the mediteranean and a mostly olive growing area.
This time of year March/April it is about 20’C max in the day flowers are out and there is blossom on the fruit trees.
These (1 to 1.5 cm) bugs are often right in the blossom. Sometimes they are very hairy and can appear yellow with the pollen.
Please can you tell me what they are and if possible, are they damaging the blossom?
In hope and with thanks
We believe we have correctly identified your Scarab as a White Spotted Rose Beetle, Oxythyrea funesta, thanks to the Things Biological website where it states: “Its distribution includes Italy, France, Malta, Morocco, Asia Minor and parts of the Middle East. It is not a particularly important species economically, though they can significantly impact grape vines and flowering wheat.” According to Csalomontraps: “The adult beetle causes damage to flowers of peark cherry, European chestnut and other spring-blossoming fruit trees and ornamental plants (e.g. peony). It damages frequently also cereals, first of all ears of rye. The beetle can feed also on many flowering weeds, i.e. different spp. of Compositae and Cruciferae. The beetle chews the petals, staminae and stigmae thus rendering the flower infertile. It can damage not only flowers in full blossom, but also in the bud stage. The grub (larva) lives in the soil, feeds on rotting plant material, it causes no damage.” Since that information is provided by a company that produces traps, the account might be exaggerated, but we believe you most likely have cause for concern.
Absolutely fantastic, thank you very much.
Now to do something to help the plants as we have hundreds of the beetles.
Again, thank you for you help as we had failed to find it in our books
Letter 2 – White Spotted Pine Sawyer
White-Spotted Pine Sawyer
Location: Hornepayne, Ontario, Canada
June 25, 2011 2:58 pm
Where I live we just call these beetles pine beetles or pine bugs. They are very common because we basically live in the middle of the boreal forest, which is predominantly coniferous. I was trying to find out what they are actually called on your website. I kept coming across the white-spotted pine sawyer, and I thought it looked exactly like the ones here except for the white spot; I thought ours were completely black. I saw one on my house today and I caught it so I could take pictures, and lo and behold, it DOES have a white spot. So I thought that was pretty neat.
The White Spotted Pine Sawyer, Monochamus scutellatus, is so named because of the white scutellum which is the triangle at the junction of the wing covers or elytra. The markings are variable, though the white scutellum is a distinguishing feature. Other members of the genus Monochamus look quite similar and it is possible that you may have other species in your area as well. This magnificent individual is a male. Males have longer antennae.
Letter 3 – White Spotted Sawyer
would like to learn more
November 13, 2009
We have found these things while camping in the rocky mountains (Wyoming) quite often. Some of them are almost three inches long with antenae. They can “sorta” fly but its pretty slow and clumsy. The white mottling seems a little bit unique to each individual.
They are nonviolent, but I cought one in my hand one time and it poked a hole in my hand, or bit me real deep (not poisonous but right into a palm tendon). It hurt for a good week. Is this a pine borer? They are neat.
Snowy Range and Big Horn Mountains, WY
Dear Interested Campers,
This is a Long Horned Borer Beetle in the genus Monochamus, most like Monochamus scutellatus, the White Spotted Sawyer. They range over much of North America. According to BugGuide, common hosts are Balsam fir, spruces and white pine.
Letter 4 – Spotted Pine Sawyer
Subject: weird bug in our house (second time)
May 26, 2012 10:17 am
got a couple weird bugs walking around our house and we have no clue what it is.
thanks for helping.
We believe this is a Spotted Pine Sawyer, Monochamus clamator, but we would not discount another member of the genus. If the beetle was found indoors, it may have come into the house in the dormant stage within firewood. Though the larvae bore in wood, they are usually very species specific and they will not do any structural damage to your home. The grubs are usually found in dead or diseased trees. You can read more about the Spotted Pine Sawyer on BugGuide.
you’re the best! thank you so much!
Letter 5 – White Spotted Rose Beetle
Location: Israel, Hadera area
March 27, 2011 5:48 am
I spotted this cluster of beetles on a flower. They seem to be very common in the area, they were all over the place. I did a little research and found that this is probably a beetle of the Genus Oxythyrea.
Is this correct?
Thanks so much for supplying your photo of what we agree is Chafer in the genus Oxythyrea. A photo of a White Spotted Rose Beetle, Oxythyrea funesta, on the Things Biological website matches nicely and the site indicates: “Its distribution includes Italy, France, Malta, Morocco, Asia Minor and parts of the Middle East. It is not a particularly important species economically, though they can significantly impact grape vines and flowering wheat.” The Scarabs of the Levant website indicates four species in the genus Oxythyrea that all look like good matches:
Oxythyrea abigail Reiche and Saulcy, 1856
Oxythyrea cinctella Schaum, 1841 (Cetonia)
Oxythyrea noemi Reiche and Saulcy, 1856
Oxythyrea albopicta Motschulsky, 1845 (Cetonia).
We believe an expert might need to examine your specimens to correctly identify the species.
Letter 6 – Southern Pine Sawyer
Beetle? Super long antennae and huge paws!
Mon, Jun 29, 2009 at 5:46 PM
Hi WTB! I’ve attached several photos of what I think may be a kind of Longhorn Beetle. We found it hanging out on our screenroom one very hot day. He was just as curious of us as we were of him, watching us and moving as we did. I have wetlands and woods behind my house.
Allyson in Florida
This is one of the Pine Sawyers in the genus Monochamus, most likely Monochamus titillator, the Southern Pine Sawyer based on photos and information posted to Bugguide which states: “larvae bore in sapwood of pine logs held in storage or pines killed by natural or manmade causes.”
Letter 7 – Southern Pine Sawyer
What is this bug?
We found this in our yard. We are in Northwest Florida, Santa Rosa County
This is a Southern Pine Sawyer, Monochamus species.
Letter 8 – White Spotted Pine Sawyer and web design suggestion
Identity of a Longhorn Beetle
Please take a look at the attached photo and tell me if it is a good enough photo to identify the beetle. We discovered it on our camping tent at 8:00AM on July 22, 2006, at the top of Table Mountain, at 6400 feet elevation, in central Washington State. Shortly after this photo was taken, the beetle flew away across an alpine meadow. There were conifer trees at the edge of the meadow. It was 2 to 3 inches long from the head to the rear end. I don’t know whether to call it a Whitespotted Pine Sawyer (Monochamus Scutellatus) or a Giant Root Borer (Prionus spp.) but I would prefer to know your opinion.
Your web site is awesome, by the way. It would be nice if the bugs were ordered in some way, and with fewer photos on each page (or something) so the page would load quicker.
Your beautiful beetle is a male White Spotted Pine Sawyer, Monochamus scutellatus. The Prionids are much stockier beetles. We are somewhat amused at your suggestion that we reorganize our site. First, our photos are “ordered in some way”. They are chronological. If you look at our 9 beetle pages, Beetles 1 is the oldest and Beetles 9 the most recent. We have individual pages devoted to specific groups of insects. The homepage has recent and timely postings. For example, we always have a House Centipede, a Potato Bug, a Toe Biter and a Pseudoscorpion on the homepage as we get so many requests to identify them. Suggesting that we restructure our page is comparable to walking into someones 50 acre, overgrown English country style garden and complimenting it, but suggesting it would be much nicer if it was redone as a formal, symetrical space. At this point, due to the size of our database, any restructuring will be the job of our archivists.
Letter 9 – White Spotted Sawyer
Bug ID question
I love your site! My daughter and I used it to identify a couple of toe-biters that we saw at an auto race track in Ottawa, Ontario last night. I thought they were really neat, and managed to pick one up (very carefully) to look it over closely, seeming to stun some of the little boys who’d been throwing things at them. 🙂 However, look as I might on your site, I couldn’t find a beetle that we photographed out on our back deck last week. It is approximately two inches long, not counting the long antennae. Also, it had small red spheres adhered behind its head, and we wondered if they were its own eggs or some type of parasitic eggs. This is located south of Ottawa about halfway to the New York state line. Thanks for any information you can give us, and keep up your wonderful work! Thanks,
Angie & Sarah
We believe that somewhere in our 9 archived beetle pages, there is a photo of the White Spotted Sawyer, Monochamus scutellatus. This specimen is a female. Believe it or not, the antennae of the male are twice as long. The White Spotted Sawyer can be distinguished from the other members in the genus by the white scutellum, the little triangle at the front of the elytra, or wing covers.
Letter 10 – White Spotted Sawyer
Cool beetle in Northern California
We found this very cool, and quite large, beetle on the front porch of our cabin in the Sierra Nevada mountains of Northern California. Elevation approx 5000 ft, on the western slope, about halfway between Tahoe and Yosemite (Dorrington, CA). After checking out your site, it looked a if this could be a “Banded Alder Borer”…however, the body coloration does not match, nor does the (seemingly) blue legs. Curious if you have any idea who he might be? We have been in this location for over 5 years, and this is the first we’ve seen of this bug. Hoping it does not represent an invasive/non-native bug which could pose harm to the trees found in this part of the mountains? Thanks
Diane (and Chris)
Hi Diane and Chris,
This is a native species, the White Spotted Sawyer, Monochamus scutellatus. Larvae bore in the wood of conifers, especially after fire or storm damage.
Letter 11 – White Spotted Sawyer
crab spider and white spotted sawyer
I sent these pics in some time ago, though I know you’re behind. Just in case the recent net troubles led to their loss, I’ve sent again. The sawyer was in my back yard in Duluth, Minnesota. The crab spider I spotted on the side of the road, again in Duluth, Minnesota. I was walking past, and thought I spied a wasp, only to look closer and find it in the clutches of this beautiful spider. Love the site!
Generally, the way we post letters now is to try to quickly (though it is never a quick process) the letters that come in on a given day at the end of the day. Then we select the most interesting letters and try to post as many as possible. Some days, it can be as many as 7 letters, though most days we are lucky if we can post 3. Sadly, many interesting letters with wonderful images never make it to the site. We are posting your Spotted Sawyer image, and even though the Crab Spider photo is quite wonderful, we already have numerous Crab Spiders and their prey on our site. Thanks again for your interest.
Letter 12 – White Spotted Sawyer
Stripey bug in Yellowstone
January 24, 2010
I visited Yellowstone NP in September 2009 and saw a rather cute bug. I am just sorting my photos out now and wondered what this bug is. It landed on my car side-mirror as I stopped for a photo.
This is a White Spotted Sawyer, Monochamus scutellatus. The White Spotted Sawyer can be distinguished from its close relatives by the white scutellum. The scutellum is the white triangular spot at the front of the elytra or wingcovers, on the thorax. It is found in coniferous forests, and according to BugGuide, it has a: “Two-year life cycle. Larvae excavates galleries in coniferous trees, often after they are damaged by a fire, storm, etc. Common hosts are: Balsam fir, spruces and white pine.“
Letter 13 – White Spotted Sawyer
Freakin’ huge bug
Location: New Hampshire
May 27, 2011 12:41 pm
We saw this bug. It was huge. We want to know what it is. Thank you for your vast bug knowledge.
Signature: Keith V
This spectacular Longhorned Beetle in the family Cerambycidae, familiarly called the Bycids, is a White Spotted Sawyer, Monochamus scutellatus. See BugGuide for details.
Letter 14 – White Spotted Sawyer
Subject: What is the beetle
Geographic location of the bug: Marlborough, MA
Time: 11:04 AM EDT
Your letter to the bugman: We can’t tell if this is a white spotted Sawyer or a Asian longhorn.
How you want your letter signed: Cory
The white scuttelum, between the base of the wings, indicates that this is a White Spotted Sawyer.
Letter 15 – White Spotted Sawyer
Subject: Longhorn Beetle?
Geographic location of the bug: Worcester, MA, USA
Time: 01:19 PM EDT
Your letter to the bugman: Hi! Today I was sitting out on my deck when I heard this beetle land. It looks to me like a species of Longhorn, I was concerned it might be an invasive. Can you help identify it? Also, got to enjoy watching a Four-toothed Mason wasp search for the right spot under the railing too while out.
How you want your letter signed: Adrienne