Carabid Ground Beetle Larva

2011 August 6

Sandy found this large, active beetle larva under a rock in the garden on June 4, 2011. It was pretty big at about 3 cm long, but skinny and not enormous. Sam found two more a few days later, so they are certainly very common. It ran and ran and ran, so to have half a chance of getting a picture I put it in a little ceramic dish [1], where it could run around but couldn’t climb the sides.

It’s certainly a predatory larva, just look at those mandibles. They point somewhat upward, so it looks like these larvae like to grab their prey from below

It had a couple of uropods on the end of the abdomen, which are common in beetle larvae. In this case, they look like they are armored.

Being a larva, it doesn’t have a lot of clearly distinguishable features, but its general appearance suggests that it is a Carabid larva.

There aren’t a lot of pictures of Carabid larvae on BugGuide (people tend to photograph adults much more than larvae), and a lot of the larvae that they have don’t get identified beyond the family level. But the one that they have identified to species that looks closest is the European Ground Beetle, Carabus nemoralis. Which, as it turns out, is a beetle that we know we have, because I just put up some pictures of one a few weeks ago. Of course, it could be one of the several other kinds of ground beetles we have. It probably isn’t practical to get a positive ID without raising them to adulthood. Which can take quite a long time.

Anyway, whatever it is, it is common, predatory, and fairly large. If nothing else, they are good to have in the garden to keep down the slugs and cutworms.

[1] We got a whole bunch of these little condiment dishes from American Science and Surplus a few months ago. They were evidently used for food service on Northwest Airlines, and AS&S picked them up cheap as surplus, probably as a result of Northwest’s merger with Delta that started in 2008. AS&S was selling them for something like $3 per dozen, so we picked up a bunch of them. They are only about 2 inches across, and pretty nice for giving small servings of treats to young children. They also have very slippery sides, so they make nice holding pens for photographing active insects that can’t fly and don’t have sticky feet.

10 Responses
  1. August 7, 2011

    I found one of these a couple of days ago, too. I’ve been looking them up, and couldn’t find them. I was glad to see this post; mystery solved!

    The one I found was chewing on a half-dead earthworm. I don’t know if it was the predator, or had just found one left behind by a robin, although I’ve never seen a robin abandon a fat earthworm before.

  2. August 7, 2011

    I hear you about the difficulty of identifying larvae in general. Hardly anybody puts up pictures of larvae, particularly young larvae. Which is weird when you think about it, because the larvae are generally much easier to photograph than the adults (which usually run faster, and frequently can fly). I guess it’s just a matter of people photographing what catches their eye, and not just what is easy to photograph.

  3. August 8, 2011

    Thanks for this posting! I’m in the Chicago area and found a similar critter that I’ve been trying to identify. A naturalist friend of mine actually pointed me to your blog as a possible match. I too am writing about what I find in my yard (although a much smaller yard than yours) and my posting on this will be going up this weekend with credit and a link back to your site as credit for pointing me to the family ID.

  4. August 9, 2011

    You’re welcome, Gary. Even though your yard is smaller than mine, I bet that you have even more diversity due to being further south.

  5. August 11, 2011

    Another great post! When you talked about them being predatory, I had other insects in mind. I had no idea they went after snails or slugs. I wonder if they can be hired out to deal with the slimies in my yard.

  6. August 11, 2011

    Supposedly, if you leave boards laying flat on the ground it makes an attractive place for ground beetles and their larvae to hide during the day. They then come out at night to eat your slugs and caterpillars. It might be worth a try.

  7. Ron permalink
    June 1, 2014

    I found one of these little critters stuck on the back of my babys head, he’s 7mo old. The head of the insect left what is almost a tiny hole in the back of my boys head. Its slightly red and irritated. Does anyone know if these insects are like a bee sting?? Or if its anything to worry about?? Obviously my baby boy can’t tell me if it hurts, but he certainly got upset when it was on his head (until I found it).

  8. June 2, 2014

    As far as I know, ground beetle larvae don’t have venomous bites, and the pain is all from simple pinching or poking. Keep an eye on it to make sure it doesn’t get infected, but that should be the only actual hazard.

    I do kind of wonder how it ended up on your child’s head, though. Was he laying in the grass, or did the larva get into his bed somehow?

  9. DESIREE J DE LA PENA permalink
    April 22, 2016

    It bit my fricken husband. Omg. It bit him, attached to his leg, and he literally had to rip it off and it bled. His leg bled. WTF

  10. Stacy Bright permalink
    April 30, 2018

    I was flea combing my small terrier mix dog tonight after noticing her scracthing a lot. I rolled her over on her back so her tummy was exposed and I observed something (which I asssumed would be a flea), had bitten her. I started flea combing her and as I was periodically dipping the flea comb in a bowl of soapy water to clean the fur and any bugs I was combing off of it, I was shocked to find this long skinny shiny semi-centipede looking insect with big black pincers up above its head, on my flea comb! This bug had somehow jumped or crawled into her fur while we were out walking earlier, and it was biting her and causing her discomfort, and I would like to know what the hell it is, and whether it’s going to become another problem pest that I have to deal with in some dystopian future where even more blood-sucking bugs will wreak havoc in pet-owners’ lives, or if this is a freak incident and one-off type shituation. I am concerned that other animals (albeit of the human species) are reporting that this insect bit them, and I’m also wondering if their bites are dangerous or toxic. I live in Los Angeles, CA. It is late April, 2018. If anyone has answers, please let me know?

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