ID Challenge #11

It’s time for another ID Challenge—can you name the organism(s) shown here?  I’ll give two points each for the correct order, family, genus and species.  Additional points will be awarded on a discretionary basis for relevant natural history comments.  Standard challenge rules apply, including moderated comments during the challenge period (you don’t have to be first to score points), early-bird points to those who do arrive at the correct answer before others, etc.  Ben Coulter has a solid lead in BitB Challenge Session #4, but there are enough challenges left in the current session that his lead is not secure—do you have what it takes to put together a run to bump him off the podium top spot?

Shaw Nature Reserve, Franklin Co., Missouri

Copyright © Ted C. MacRae 2011

43 thoughts on “ID Challenge #11

  1. I’m guessing that’s a tachinid fly (Order Diptera, Family Tachinidae) larva on a caterpillar (Order Lepidoptera). I figure a wasp would have oviposited inside the caterpillar, whereas a fly would lay an egg externally that hatches and the larva burrows inside.

    Or perhaps instead of a macro you’ve taken to astrophotography, and that’s a sandworm (Shai-Hulud) porpoising through the dunes of the desert planet Arrakis.

  2. Hooray, it’s a parasitoid larva attached to another larva of some sort. The parasitoid looks like a dipteran, and I think the host is a tiger beetle.

    Order Coleoptera
    Suborder Adephaga
    Family Carabidae
    Subfamily Cicindelinae
    Tribe Cicindelini
    Cicindela tranquebarica

    I actually had some rational listed here, but lost my post, and it’s too late to retype it all. I spent some time with Hamilton (1925), and I think C. tranquebarica is an acceptable match based on the setae of the abdominal segments, and the sclerotization. Bram and Knisley (1982) found Anthrax parasitation rates as high as 78% in this species in a Virginia study. I was going to guess sexguttata or unipunctata but I think this species might fit better (we’ll see how that gamble pays off).

    And for the parasitoid:
    Order Diptera
    Superfamily Asiloidea
    Family Bombyliidae
    Subfamily Anthracinae
    Tribe Anthracini
    Anthrax georgicus, formerly known as A. analis, and I believe, the only Nearctic Anthrax to utilize cicindelids as larval hosts. Most are parasitoids of Hymenoptera.

    For some appropriate natural history: Anthrax georgicus lay their eggs at the entrance of larval burrows of 2nd- and 3rd-instar tiger beetles. The fly larvae attach themselves externally, often at the thorax or at the 5th abdominal segment, and slowly feed until the 3rd-instar host approaches maturity. At this point, the Anthrax larva hastens its development, killing and consuming the host. They are considered parasitoids because they do kill their host, whereas true parasites technically don’t.

    • You’re good on the basics, although the tiger beetle is not a Cicindela Full points for the parasitoid = 8 pts, plus 4 pts for host order and family = 12 pts. Also 2 bonus points for the concise, on-point ecological summary.

      Total = 14 pts

  3. Well, that looks like a really big caterpillar with a maggot crawling out of it, so I’ll jump right to one of the Giant Silkmoths/Royal Moths (Lepidoptera:Saturniidae) being parasitized by a Tachnid fly (Diptera:Tachinidae)

    Not too many of the Saturniidae seem to be that particular creamy color, so I’ll just go with one that is: Anisota stigma. As for the presumed tachnid fly, how about Exorista larvarum? They seem to parasitize relatives of silkmoths.

  4. Ted,
    I would say that it is an ectoparasitic hymenoteran on a cicindelid larva. Since tiphiids of the genus Myzinum have been shown to parasitize cicindelids, I will go with that. Insecta: Hymenoptera: Tiphiidae: Myzinum sp.

    • Hi MIke,

      You got the correct host family, although I can only give it one point due to spelling and one point for the implied but not stated order (sorry, them’s the rules!).

      The parasitoid is in the order Diptera, but you get a pity point.

      Total = 3 pts

      • Okay, this one has me pretty much stumped. As far as I know, flies are the only insects with legless larvae. However, after spending hours browsing through hundreds of photos, I haven’t found anything that looks right. Since I wasn’t having any luck with flies, I also checked out parasitic wasps. No luck there either, but I did find this photo of parasitic wasp larvae that was too cool/gross not to share. I still think this is some sort of parasitic fly larva, though. I’m going to take a guess and say Order–Diptera, Family–Tachinidae, Genus–Billaea, and just for the heck of it, I’ll say Species–rutilans .

        Since I’m guessing that the smaller organism is a Billaea rutilans larva, then that would mean the larger, host organism is most likely the larva of Enaphalodes atomarius. So for the larger organism, I’ll say Order–Coleoptera, Family–Cerambycidae, Genus–Enaphalodes, and Species–atomarius.

        • Is it too late to change my answer :)? I knew that the larger creature seen in this photo looked familiar, but I just couldn’t place where I’d seen it. When I read the part of your post “BugShot 2011–Final Thoughts” about fishing for tiger beetle larva, that’s when it hit me. I did a quick search of BugGuide to see if I could find a matching photo, and I found this photo from Chris Wirth showing a tiger beetle larva with a parasite that looks very similar to yours. He says one the BugGuide post that he thinks the larva is from a fly in the Genus Anthrax, and since I have nothing better to go on I’d like to change my answer for the parasite to Order–Diptera, Family–Bombyliidae, Genus–Anthrax, no clue on the species. As for the host, the pattern of bristles looks like those of the metallic tiger beetles. So for the tiger beetle larva, I’ll say Order–Coleoptera, Family–Carabidae, Genus–Tetracha, and since they’re found in Missouri, I’ll say Species–carolina.

          • Much better – you get 6 pts for a genus ID on the parasitoid plus a bonus point for that Chris Wirth photo (I hadn’t seen it). As for the host, congratulations on being the only person to identify the correct genus. Unfortunately, T. carolina does not occur this far north in Missouri, leaving T. virginica as the only possibility. Still that’s also worth 6 pts.

            Total = 13 pts (just one behind the great Ben Coulter!).

  5. Both individuals shown here are larval insects albeit from very different orders. The tiny larva is probably that of the parasitic wasp Methocha, and the larger larva is its cicindelid host, probably a member of the genus Cicindela . I have no idea as to what species either of these individuals belong, but I can at least make a decent guess on the tiger beetle. I have no idea what species the wasp (if it is in fact a wasp) larvae belongs to.
    Tiny Larva
    Order: Hymenoptera
    Family: Tiphiidae
    Genus: Methocha
    Species: stygia ?
    Big Larva
    Order: Coleoptera
    Family: Carabidae
    Genus: Cicindela
    Species: formosa ?

  6. Pingback: BugShot 2011 – Final Thoughts « Beetles In The Bush

  7. Hmmm… I’ve got no clue what this is… Anyway, I’ll give it a try.

    I am thinking something parasitic, could be a wasp (Hymenoptera) or a fly(Diptera). i think I’ll stick with the flies. Could it be tachinid?


  8. I suppose I’d better guess in the hopes of some pity points: the more dorsal larval insect is a species of Eulophus (Insecta, Chalcidoidea, Eulophidae) and the more ventral insect is a caterpillar (Insecta, Lepidoptera).

    The setae on the caterpillar-like organism look too long and fine to have come from a beetle larva from under bark (another possibility given the pale colour). The maggoty thing on top seems to have a head capsule-like ending, so that would rule out tachinid. Otherwise, my reasoning is based entirely on general characters and Eulophus species being an external parasitoid of Lepidoptera and other insects. In other words, I’m guessing.

  9. OK, I see now that this is evidently something you photographed at Bug Shot, and it sounds like you spent a lot of time fishing for tiger beetles with all the people who have commented, and the fact that the big one is non-green and a bit bristly has been bugging me all day because that doesn’t sound so much like a silk moth, sooooo . . . can I change my answer?

    I now kind of suspect that the big one is a tiger beetle larva (Coleoptera, family Carabidae, probably a common one, so genus Cicindela).

    I’ll stick with the little one being parasitic. A wasp, perchance? A small one, so Hymenoptera, family Braconidae?

    • Yes you can change your answer – I was dropping hints hoping people would catch on.

      Okay, the host is indeed a tiger beetle, though not Cicindela, so you get 4 pts for that (but now I have to take back the pity point from your first answer). I also have to take back the 2 pts for your earlier answer of Diptera and replace them with a single pity point for your new guess of Hymenoptera. That still works out better for you though.

      New total = 5 pts

  10. Pingback: Bee Fly (Anthrax georgicus) | Central Florida Critter of the Day

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