Aquatic Larva

Aquatic Firefly Larva

Subject: Unknown aquatic macroinvert
Location: Huntington, Indiana
October 11, 2014 9:27 am
Hey bugman!
The college ecology class I teach found this critter while sampling a small, wooded creek on our campus. I’ve shown the picture to a couple of aquatic ecologists I know and none of them have been able to identify it yet. The best we can come up with is that it is some sort of free living caddisfly (Trichoptera). The “shell” looks a lot like an aquatic isopod though! It definitely had only 6 legs. ~1.5-2 cm in length.
Any ideas?
Signature: Collin Hobbs

Hi Collin,
We haven’t a clue as to the identity of your creature, but we wonder if it might be the larva of an aquatic beetle because it really resembles a Firefly Larva or a Netwing Beetle Larva.  We are not certain if there are any aquatic beetle larvae that look like this, but we believe that is a more likely candidate than the larva of a Caddisfly.  We will try contacting Eric Eaton to see if he can provide any information.

Eric Eaton confirms our identification
On my way out the door, but….
Looks like a firefly larva to me, and there are species that prey exclusively on aquatic snails….

Ed. Note:  Beetles in the Bush and Cambridge Journals Online both have articles on aquatic Firefly Larvae.

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Location: Huntington, Indiana

9 Responses to Aquatic Firefly Larva found in a Creek

  1. Collin says:

    Hey, thanks a lot! A quick google search definitely supports your identification. There are some species in the genus Photuris that have larva that look almost identical to the one we found. Plus there were a lot of snails in that creek, so it makes sense.

  2. Bambi Hanson says:

    Just noticing many of these glowing in our gravel driveway and adjacent lawn…in the woods, over the past several weeks. You are identifying as Aquatic Firefly Larvae. 10/2014.
    We have no creek. But have been inundated with rain in July, Aug and now Sept. Some standing water is creating tiny ponds in the lawn. The bugs are not in the water though.

  3. Richard says:

    I found two of a VERY similar larva in a small backyard (plastic) pond in MD. I was draining the pond because of mosquito larvae. They curl up like isopods when disturbed, and move quite lethargically. I have to assume there were IN the water. I thought they were dead, but omce the pond was mostly drained, they started moving around slowly . They are probably about a half inch in length fully extended. Much larger than the fireflies I’ve seen in this area.

  4. Lynn Faust says:

    Definitely Photuris firefly larva. Very common along creek banks. Was it totally submerged? They have the ability to remain submerged for a little while but normally they are in The Damp soil along Creek Banks.

  5. Richard says:

    The ones I found were totally submerged. I was draining the pond out (along with hundreds of mosquito larvae) to remove it, and these guys were at the bottom. Very lethargic. I thought they were dead, but when I’d look a few minutes later, they’d be in a different position. Mostly went from curled up, to not. If I disturbed them, they’d slowly curl up again. Had never seen these before!

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