What’s your name?

A major joy of living in Texas comes from our biodiversity, something evident with more than 30,000 known insect species (it’s accepted that we lack a true count of insect diversity here or anywhere else in the world given insects represent more than half of the planet’s total biomass).  And in any given winter, insects rarely vanish for more than a few days, give or take sufficient warmth.

But sunshine does not mean warmth.  This is a fact insects and arachnids learn the easy way or the hard way.  The easy way is they stick their head out long enough to realize their mistake and immediately vanish back into the warmth of their overwintering hideout; the hard way is they leap into the light only to learn too late that cold temperatures spell their demise.

Before the gray overcast of our recent snow storm settled in, a few winks of sunshine bathed my patio long enough to lure critters out with empty promises of comfort.  The patio floor is now littered with half a dozen carcasses of leather jackets (crane fly larvae) who didn’t heed my warning about not going into the light.  Only in retrospect did I realize they were too young to have seen Poltergeist.

Yet another critter that made an appearance on the last sunny day did listen to me and smartly made a u-turn after recognizing the sun’s deception.  Over the course of about 90 seconds, this beetle larva covered a short circular distance in the open as it came from and returned to its bed beneath the wall.

An unidentified beetle larva scampering across the patio floor (2010_01_22_048737)

Had I not been standing there watching the goings on and thinking of Carol Anne the whole time, I would have missed the brief visit.  By the time I fetched the camera the young beetle had completed three quarters of its round trip, so I snapped a few hurried images before it scrambled out of sight.

An unidentified beetle larva scampering across the patio floor (2010_01_22_048743)

About one inch/2.5 centimeters long, its size and general appearance said it was either a rove beetle (a staphylinid; Staphylinidae) or a ground beetle (a carabid; Carabidae).  Telling the two apart requires details I can’t determine from the few bad images I snapped, such as the number of leg joints and number of claws on each foot.  Also, because this cold insect was covered with dust and dirt from under the wall where it had been sleeping away the winter, important aesthetic details are unfortunately obscured.

An unidentified beetle larva scampering across the patio floor (2010_01_22_048780)

Were I to guess, I’d say it’s a rove beetle larva.  That’s based on experience.  In ten years in this home, at least five rove beetle species have visited the patio regularly, two of them being large species.  I have on many occasions seen adults scampering into hideaways beneath the walls.

Many ground beetles have visited the patio in that time as well; however, the species have not been as consistent and the sizes have been mostly small.  The difference is environmental: the ground outside the patio represents heaven for rove beetles but is less inviting for ground beetles.  Five paces away in the grass and sandy drainage areas, that ratio flip-flops and rove beetles become the minority.

So all I know is that a respectably sized beetle larva is sleeping beneath the patio wall.  Its identity remains a mystery.  And whether or not I see it again, I know its kith and kin will visit often in the coming warmer seasons.

11 thoughts on “What’s your name?”

  1. Hey Jason, how do you even start to go about identifying a beetle larvae? Is there a field guide for such things? I frequent bugguide.com, but I don’t think it would have helped me on this one. I also have an outstanding caterpillar guide – but again, wouldn’t help here.

    1. Truth in advertising, Amber: Some species might be documented well enough to figure out, but most of them I suspect can only be narrowed down to a group, such as family, tribe, genus and so on. You could always capture the larva and allow it to develop, though that’s very much against the grain of my approach.

      In this case my hope was to at least pin it down to family or superfamily, if not tribe or genus. That’s the best I had hope for since I doubt I had a chance to know its precise identity. (Especially if it was a rove beetle since that’s the second largest group of beetles.)

      I did use bugguide and online research to figure out the anatomical cues that usually differentiate carabid larvae from staphylinid larvae. Then size and location could help pin it down further. But ultimately I had no real hope of getting to the species level without being very lucky.

    1. Thank you, Kevin!

      And I’m embarrassed: I thought of soldier beetles but couldn’t remember one of comparable size that I’d seen around the patio (though certainly large examples are in the area–which is why I should have given more weight to the possibility).

      If you don’t mind me asking, how can you tell? Adults are one thing, but when it comes to larvae I’ve discovered someone like me without specialized experience and/or education has little chance of narrowing down the field of candidates. I’d love to pick up a trick or two that will help in the future.

  2. Haha…don’t be so hard on yourself. I’m actually in graduate school for entomology, and beetles are my favorites. Cantharid larvae just have a particular “Gestalt” or general appearance to me, but what really seems to set them apart from some of the similar groups is the plumpnesss of the segmentation. One of my friends once described them as looking like little Michelin men, and I think the analogy is apt. They also have a sort of velvety appearance, and their mandibles aren’t as formidable as most staphylinids and carabids. Feel free to contact me with any future questionable IDs. I can’t say I’ll be able to deliver, but I’ll put in an honest effort. Thank YOU for liking beetles 🙂

  3. Something else I should have mentioned in the last post. Here are several works to guide you with identifications…

    -Stehr’s Immature Insects Volume II.. .Both volumes are excellent, but Volume II contains Coleoptera
    -American Beetles Volume II…Volume II is a much larger text and contains many more families for adult ID’s
    -Borror and Delong’s Study of Insects (7th edition). This a text for family identifications of all insect orders, but contains many Coleoptera families as well.
    -Peterson field guides-Beetles.

    Unless you’re particularly stuck on larval ID’s (which it doesn’t include), I would begin with Peterson’s Beetles. It’s an inexpensive book and has a lot of illustrations for family level ID. If you have the money, pick up American Beetles Vol. II and Immature Insects Vol. II. The latter two are the go-to guides for many entomologists.

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