Biggest bug I was ever bitten by

One day this summer I was at the school where the food pantry is held, and a school landscape employee was spraying weeds. He called out in surprise, that there was a really big bug right on the nozzle of the herbicide applicator. I ran over to see and apparently was the only person willing to pick up this huge black beetle. I decided to take him home, since my husband is a beetle fancier, and rummaged around for some sort of container for him. Finally I found a kleenex box, emptied it, and with the help of a young girl gathered leaves and sticks to make a cozy temporary home. The little girl was scared of the beetle but her feelings toward him began to turn warm and nurturing when I invited her to help furnish his house. She hadn’t gotten up to touching him by the time we put him in and taped a piece of paper over the top, but given more time I feel sure she would have come around.

Here’s our prize, emerging from his house (all the furnishings got shaken to a corner by the car ride).

Ergates spiculatus Spined woodborer,emerges.jpg

He crawled on my arm and hand for a while and then I must have annoyed him because he bit me with his mandibles—made me jump! The bite made a 1/8 inch cut that did bleed, but alas left no scar for me to show off while admitting how I had completely deserved it. Below he’s on my husband’s arm.

Ergates spiculatus Spined woodborer - 15.jpg

And for better scale,

Ergates spiculatus Spined woodborer,4Scale.jpg

We were able to identify him as one of the longhorned woodboring beetles, the Spined Woodborer or Pine Sawyer Beetle (Ergates spiculatus). One clue to differentiating him from another similar species was the spininess of his thorax, visible in this photo. The spines are on the sides of his thorax, while the yellow arrows point to the palps which unfortunately are blurry in this picture.

Ergates spiculatus Spined woodborer Head.jpg

Here the palps are clearer.

Ergates spiculatus Spined woodborer palps.jpg

The palps are sensory organs for the beetle. Mandibles cut up food and maxilla help manipulate it. The parts of a beetle’s head are shown in this illustration.

Beetle head anatomy.jpg

After irritating this beetle so much, we stopped before getting any good photos of his underside, though we could see intriguing edges of fibrous stuff. Here’s someone else’s great picture of what the description says are “velvety” underparts. The eyes and two pairs of palps are also shown.


Etymological note: ergates is from the Greek, worker; spiculatus, from the Latin spiculum, a little sharp point (diminutive of spicum, a sharp point). The English word “spike” may derive from this Latin word, or may have a more indirect derivation; there is a Proto-Indo-European root *spei-, sharp point. [Proto-Indo-European is the common ancestor of all modern Indo-European languages. It dates from before writing, so it has been reconstructed from study of related words in various languages, and derivation of rules by which sounds change over time. The same method has been used to construct Proto-Germanic. In historical linguistic studies, the asterisk next to a “word” means that it is a reconstructed root.]

One site says this is the largest beetle in North America, up to 65 mm (2.6 inches) in length, but I could not confirm its status as champion big beetle. At any rate it is plenty large, and I wondered if it was one of those beetles, the larvae of which cause extensive die-off in our Pacific Northwest forests. A publication on wood-borers from Washington State University reassured me: “Keep in mind that almost all of our native species of long horned beetles feed in dying or stressed trees and do not attack healthy trees”. According to them, Ergates spiculatus feeds mostly on dead/dying/stressed Douglas firs or Ponderosa Pines.

That information has a different implication, however, at a time when climate change may be stressing northern forests with increased temperatures and long droughts, causing millions of trees to fall into that “stressed” category. British Columbia has reportedly lost about half of its pine trees to a borer no larger than a grain of rice, which spends most of its life boring beneath the bark, a process continued by its larvae which cut off the nutrient and water supply while feeding. To make matters worse, “The beetles also introduce a distinct blue stained fungus that holds back a tree’s natural defences against the attack, delivering a lethal larvae and fungus combination”.

Our trees look pretty good, though, so without hesitation we turned the big biting bug loose on one of them.

Ergates spiculatus Spined woodborer on tree.jpg

11 thoughts on “Biggest bug I was ever bitten by

  1. I ran into one of these beetles the other night while letting my dog out. it was on the underside of my awning. Thanks for the great pictures I was able to show my husband and friends exactly what it looked like!

  2. We got one in with some firewood (or at least that’s we assumed) that came from higher elevations- it landed ON my wife’s shoulder as she was getting out of her car. She was sure I had thrown something at her! This one was about 4 inches long. I found it later and had it ID’d by the extension agency. Too bad, they threw it out after that, my son could have had a great science project for school as they were studying bugs at the time!

  3. I caught one an hour ago. I put it in a container and am freezing it overnight. I do my own landscaping and work at garden nurseries. I have some knowledge on the damage these cause in California. Will bring it into work tomorrow for show and tell. Never seen this specific one in person. Maybe in Tahoe I have but not certain

  4. Wow! Thanks for the great pictures and information. I got some really good pictures of the one I found but not as great as yours! I live in Virginia Beach and I have seen the same one for two nights. At first I thought it was an American Cockroach but then I realized it was a type of beetle. I also read where they can be beneficial and so let him alone after photos. I’m still researching this one because I’m still impressed by its size!

  5. 8/8/19 Just found a 2 1/4 inches. After examining it and finding out what the name was, we let it go. It is the biggest bug that we have found. Eugene, Oregon

  6. I live in northern Manitoba Canada. We are infested with these beetles in the summer. Locally we call em pinchers. They will actually veer off course to chase you when flying. You know ones on you when you feel the thud of them flying into you.Never been bit but they say it hurts! I usually see 20 or so a day during July/August. Very fascinating creatures.

  7. I was just getting ready to snooze through a CNN report about The President and the Pandemic. Lights out and only the TV on. I thought I saw something crawling around on the front of my shirt. At first I thought it was just a large caterpillar of some sort but there seemed to be too much movement going on. I swept it off with my hand and it hit the floor with a thud. Lights on and I came face to face with the biggest ugliest honkin’ beetle I have ever seen. Well over 2″ long not counting two very long antennae. Managed to capture it and put it into a plastic sealed container.
    I looked it up online and it is without question Trichocnemis spiculatus. Ponderous Borer Beetle. But this is Southern Ontario. Not Western North America or California. How did it get here? Most of all ; how did it get into my house ?.There are no Douglas Fir or Ponderosa Pine trees anywhere near here.
    On Monday I will call the Entomology Dept. at University of Guelph Agricultural College.
    I live in an area surrounded by farm fields and forests. My property backs onto Grand River Conservation Authority. I am used to seeing unusual things. We have Hummingbird Hawk Moths, Cecropia and Polyphemus Moths and other species I never saw when we lived in Niagara area for 50 years. We also have a Pileated Woodpecker living in a dead Ash Tree close to our house.
    It pays to keep your eyes open. But this bug couldn’t wait to be found outside. It came in to meet me ; up close and personal.

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