The Bug Geek

Insects. Doing Science. Other awesome, geeky stuff.

A weird, wingless discovery

One thing I love about sorting my trap samples is that I never know exactly what I’m going to see! Add to that the novelty of specimens from the far north, and the inherent diversity of insects, and it’s pretty much guaranteed that I’m going to see at least a few new-to-me species every time I sit down at my lab bench.

This term I’ve had an undergraduate student volunteer, Michael, working with me.  He quickly demonstrated that he’s not only interested but also talented, progressing from sorting to pinning and pointing specimens (a task I’m notoriously anal about and rarely relinquish to others – everything must look *just so* – but Mike has proven up to the challenge) in a few weeks.

He’s also got what I’d call a “good eye”.  While he may not know all the formal taxonomic names or anatomy of everything, he’s been quick to pick up on the visual cues and patterns of different groups of insects, and often points out interesting new things he finds in the samples he’s working on.

The other day, he looked up from his dissecting microscope and asked, “Do all wasps have wings?” He had been taught, you see, that two pairs of membranous wings was one of the defining characters of the wasps he was to extract from his samples.  “This looks like a wasp, but it doesn’t have wings.”  I came over to his station to take a peek and saw this:

Gelis sp., a wingless female parasitoid (Ichneumonidae)

A wingless female parasitoid wasp. Photo by Katie Sim (because I am useless at using our lab microscope camera and Katie can take great photos of tiny things like itsy-bitsy spider genitals. )

I saw that he had correctly nailed this critter as a Hymenopteran, and that, indeed, it had no signs of wings.  In a moment of blinding genius, the first words that fell out of my mouth were: “It’s an ant!”  Then, “No, wait…”  Although the tiny, reddish, long-legged animal did rather resemble an ant, the abdomen, mouthparts and antennae were all wrong. A wingless wasp it was! How cool!  I shared Mike’s excitement over the discovery, as this was a first for me as well.

I did some Googling and Bug Guide searching, and found that a number of parasitic wasp groups had wingless females.  (I also read that many of these were ant-mimics that would sneakily attack ant-tended hoppers and their nymphs, so felt somewhat better about my earlier ID gaffe).  Since there were too many possibilities, I called in the reinforcements: the post-doc in our lab also happens to be our resident wasp expert. Laura kindly agreed to take a look at the tiny critter and quickly confirmed her initial suspicions: it’s a member of the family Ichneumonidae, of the genus Gelis.  And that’s about as good an ID as we’ll get, because apparently the Gelis sp. group is ridonculously difficult to pick through.

As far as their diet goes, Laura had this to say: “They attack a variety of things, generally things in silk cocoons.  So, they can be hyperparasitoids on cocoons of Ichneumonoidea, or primary parasitoids on spider egg sacs or small Symphyta and Lepidoptera cocoons”.  So much for my maybe-it-looks-like-an-ant-so-it-can-attack-ant-tended-hoppers theory.  This wasp’s winglessness may therefore be a reflection of her preferred food sources: egg sacs or cocoons attached to low-lying vegetation are perhaps easier to access by land, rather than by air.  By not “wasting” energy on the development of wings or on flight, the female wasp might be able to devote more energy to the production of her eggs and eventual offspring.

I love this little discovery in part because parasitoids are awesome and wingless parasitods are extra-cool.  But I think I love it MORE because it involved the combined efforts of four people to pull all the pieces together (thanks Mike, Katie and Laura!)

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11 responses to “A weird, wingless discovery

  1. Cheri M. Abraham February 22, 2012 at 12:58 PM

    Interesting find. I was also like.. Yay.. a parasitoid without wings !!!???wow.. … and then… ohhh.. there are others too???….I’ll have to dig something more to read about how these wasps do what they gotta do without the wings to move around..Thanks for the post

    • TGIQ February 22, 2012 at 1:51 PM

      Thanks for stopping by and commenting, Cheri! I see you’re a fellow ento grad student – cool! Isn’t it great how there is always something new to learn about in this field? :D

  2. Ted C. MacRae February 22, 2012 at 1:35 PM

    An interesting find. The advantage of being wingless in this case still puzzles me. Crawling up and down vegetation and over the ground is also energetically expensive – not to mention the reduced range available to search for suitable prey and the likely increased risk of predation during foraging. Maybe prey is abundant and easy to find, and the risk of predation is somewhat mitigated by its ant-like appearance. Each new discovery raises many new questions!

    • TGIQ February 22, 2012 at 1:50 PM

      Perhaps it makes more sense in the context of an arctic (tundra) environment? The vegetation is all very low and dense – very little vertical stratification of prey items, and plenty of cover from overhead predation (of which there is comparatively little). Also, since spiders might be common prey, spiders are CRAZY ABUNDANT in terrestrial northern systems compared to other taxa.

      • Ceratina February 24, 2012 at 9:13 PM

        Having read Heinrich’s “Hot Blooded Insects” I’m going to take a wild guess that it takes much more energy to get warm enough to fly than to walk. Even bumblebees in warmer climates walk to save energy (I see them on foot a fair bit in my Seattle yard).

        • TGIQ February 25, 2012 at 6:44 AM

          That’s a very sensible theory. And actually, now that I think about it, I can recall at least one paper that looked at insect activity levels in an arctic site and it found that ground-dwelling/walking insects generally remained active at lower temperatures than fliers. (Also, they were not affected by strong winds in the same way, obviously.) Thanks for chiming in, Ceratina! :)

  3. Alex Wild February 22, 2012 at 7:31 PM

    I was fascinated by these little wasps the first time I saw them, high in California’s Sierra Nevada. Like you guys it took me quite a while to figure out what it was.

  4. Dave February 23, 2012 at 8:22 PM

    Great find and great picture! I didn’t think ichneumonoids (my first guess!) indulged in wingless females too. But without wings, you’d never get it through the typical ichneumonid key, so thanks to Laura for the id.

    Wingless Ceraphronidae (Ceraphron sp.) and Platygastridae (Baeus and Trimorus spp.) aren’t uncommon in aspen parkland soil-litter samples. Baeus females are after spider eggs and Trimorus after carabid beetle eggs, so the winglessness makes a certain sense, but equally tiny Mymaridae egg parasitoids show up on a regular basis and invariably have wings. Ditto for winged female Ceraphron. There doesn’t seem to be much on the biology of Ceraphronidae, but I’m assuming they are mostly egg parasitoids too.

    Zazzle mugs arrived today (after the Canadian Gov’t took their little custom’s bite). My wife was delighted at her belated Valentine’s gift and I even got a spontaneous kiss!

    • TGIQ February 27, 2012 at 6:34 PM

      Yes, thanks to Laura indeed! I would have been up the creek without a paddle if she hadn’t stepped up to the plate :) I know very little about wasps generally, and parasitoids specifically; the info you’ve got there is a nice bonus, thanks!
      Glad the mug arrived (hopefully it looks ok!) and gladder that you got a kiss out of it :D

  5. Mark August 18, 2013 at 1:04 PM

    Quite interesting (the photo’s). I am researching this wingless parasitic wasps, too;
    But you give less information concerning their lifestyles… I mean what about the-ant-like-wasps native country? I was googling but I couldn’t find the info; Do they live in Northen countries like Russia for example? … And I’d like to know more about their habits I mean what they like (as I could get it they like meat but anyway…) and what they don’t like and what they extremely don’t like, too.

    Please reply

    Mark

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