Readers’ wildlife photos

Reader Andrée Sanborn from Vermont sent a series of pictures of an unusual insect that were taken in July (but sent in mid-October). Her captions are indented.

Case-bearing Leaf Beetle larva (Cryptocephalinae)

July 22, 2017

This was an exciting find for us. It wasn’t just a lifer, it was one of an entire subfamily that I had never known or seen. We all know leaf beetles to some extent: seed beetles, tortoise beetles, calligrapha beetles, the Colorado potato beetle, flea beetles, even ladybugs. But this is the larva of another: a case-bearing beetle“Larvae are casebearers, living in and protected by a case constructed of their fecal matter and sometimes plant debris. The case is shorter than the larva that remains folded inside it. Eggs are laid in carefully sculpted packets formed from feces and abdominal secretions. . . “

I saw a minute lump (or dot) on an alder leaf. A flea beetle was inspecting the lump. I could tell immediately that this was a living creature because of the color and pattern. I did some shots, took the leaf, and took it home for inspection. We had a great time figuring out what it was: we went through sawfly larvae, spiders (at one point, it looked like spider legs coming out of the case), until finally, after all the photos and observations, I thought of case bearers. The only case bearers I knew of at that point were moths, but I searched for others and found Cryptocephalinae. Discovering the ID of a new insect without help from scientists is one of the most exciting things to do. Of course, what those entomologists have taught me through discussions of their finds and my photos is what prepared me to be able to figure this out. That excitement is why I have submitted only this individual in this email.

I kept the larva in a mason jar with alder leaves for a while but I didn’t like how the life cycle was progressing so set it free.  Unfortunately, I have never found another. I so wanted to see the adult.

By the way: if anyone is interesting in insect hunting, I suggest groves of alders. They sustain a huge assembly of insects and, therefore, birds, especially warblers, that feed on them.

The fecal-looking larva in the field:

The rest of the shots were taken inside:
A photobomb from one of the cats of one of my daughters for Caturday (I shouldn’t judge. My Oliver is awful.):
To give an idea of what adults look like, here’s an adult from what is probably a different species, Cryptocephalus nitidus:

16 Comments

  1. Posted November 22, 2017 at 8:04 am | Permalink

    Great find – thanks for sharing!

  2. Posted November 22, 2017 at 8:14 am | Permalink

    Thank you for posting these, Dr. Coyne. It’s great to see summer again when now snow is on the ground. I mucked up the caption for the obnoxious cat of daughter: I shouldn’t judge the cat because my Oliver is way more obnoxious than any of her cats.

    • Christopher
      Posted November 22, 2017 at 9:02 am | Permalink

      Something I’ve said more than once in the last three months of caring for my son’s cat :

      “Get your butt out of my cheese!”

      Of course, how dare I pay attention to my food when I should be paying attention to him! Obnoxious is the default factory setting for felines (Magellan is currently sitting in between me and my breakfast plate on the kitchen table) yet one cannot help but feel thrilled that cats deign to pay us any attention. 😻 Caring for a cat is very much like being in a relationship with someone you know is way out of your league.
      Lovely photos by the way.

      • Posted November 22, 2017 at 10:14 am | Permalink

        You’re right. Perhaps my daughter, who runs the county animal shelter (Vermont is no-kill), has refused to allow me to trade-in Oliver, which I half-seriously wanted to do because of his abnormally gruesome and vile mousing habits. She says I’m stuck. (She’s also put me on a statewide no-adopt list to prevent me from acquiring more cats than she can care for upon my demise.)

        • Posted November 22, 2017 at 10:15 am | Permalink

          I wish I could edit comments after posting. I meant that perhaps this daughter is more obnoxious.

  3. busterggi
    Posted November 22, 2017 at 8:42 am | Permalink

    If I did believe in god I’d thank him for creating so many delightful beetle species.

    • Posted November 22, 2017 at 10:25 am | Permalink

      I’ve had so many thoughts about that, sort of. As far as I can gather, there is at least one species of moth hosted by every plant here where I live. That blows my mind. Could Nature be streamlined / simplified? Then you break that chain of life and don’t know what the consequences would be. If only someone could code a simulation of the effects of extinction of one solitary species . . . I’d buy that in a minute. If nothing else, it would help me understand these connections in a way I can’t even fathom yet. The complexities of insects and their lives is astounding.

  4. Mark Sturtevant
    Posted November 22, 2017 at 9:15 am | Permalink

    This is very interesting! I have never seen these, but heard of them. Your pictures are first-rate.
    I see from the link that these are related to the warty leaf beetle, and I wonder if those are the ones that mimic caterpillar poo. I have probably seen those, but of course assumed they were the model, not the mimic.

    • Posted November 22, 2017 at 10:39 am | Permalink

      🙂
      Praise from you has now entirely made this a wonderful week. Thank you, Mark.

      I’ve never heard of the warty leaf beetle, and will be looking it up ASAP. I’ve seen Canadian Tiger Swallowtail first or second instar cats that looked like they used poo or were designed to mimic it. I never had read of that in my readings before (but with bugs there is so much to read). Poo-mimic larvae would be a great book.

      • Mark Sturtevant
        Posted November 22, 2017 at 1:35 pm | Permalink

        Poo mimicking insects and spiders, even. Many swallowtail cats specifically mimic bird poo, with surprising anatomical correctness. The champions are the larvae of giant swallowtails.

      • Mark Sturtevant
        Posted November 22, 2017 at 1:37 pm | Permalink

        Occurs to me that maybe your case bearing larvae are using their poo to sort of mimic caterpillar poo, which will commonly sit on the tops of leaves. Not sure if that is right, though.

  5. Greg Z.
    Posted November 22, 2017 at 9:32 am | Permalink

    Folks interested in the evolution of poop use by chrysomelid beetles can check out the research of Caroline S. Chaboo (University of Nebraska State Museum).

    • Posted November 22, 2017 at 10:40 am | Permalink

      Thank you, Greg. I’m googling right now.

  6. Dee
    Posted November 22, 2017 at 9:47 am | Permalink

    Great photos, wonderful story! Love the cat.

  7. Posted November 22, 2017 at 6:37 pm | Permalink

    The beetle looks crappy.

    Sorry for the pun, but I had no choice. It seems like a fascinating species. Speaking of leaf beetles, I was surprised at how long ladybugs’ wings were and how they managed to fold them up into such a small shell.

    • busterggi
      Posted November 22, 2017 at 6:42 pm | Permalink

      That’s why I always throw some ladybugs in my luggage when packing for a trip. They’re so good at it.


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