First parasitoid of spring

Since the beginning of March, the signs of spring have been trickling in: arrival of turkey vultures and red-winged blackbirds; migration of blue-spotted salamanders on the first rainy night; skunk cabbage blooming; various insects and spiders becoming active again.  This week another milestone was reached: I checked my assorted bags and jars of overwintering galls and leaf mines, and I found something moving around in one of the bags:

Ormyrus, a parasitoid of cynipid gall wasps.

Isn’t she a cutie?  This 3 mm wasp is a member of the genus Ormyrus, which includes 16 described species in North America, all of which are parasitoids of gall wasps, as far as is known.  She emerged from the little reddish gall in the photo below (if you look closely you can see the exit hole).

Round bullet galls on white oak, caused by Disholcaspis quercusglobulus.

I collected these galls in February, suspecting that at least the smaller one was parasitized.  Normal “round bullet galls” look more like the one on the right, though even this is smaller than a typical one.  Like the vast majority of galls on oaks, they are caused by wasps in the family Cynipidae.  This particular gall is caused by Disholcaspis quercusglobulus, and apparently the unparasitized adults emerge from their galls in October.  Since I brought these galls inside, this isn’t necessarily the time that the Ormyrus parasitoids are supposed to emerge (in fact, I had one emerge from the same type of gall in May of 2005), but nevertheless the appearance of this wasp is a sign that I need to start checking every day if I want to find my emerging insects while they’re still alive.  Stay tuned for the next arrival…

Thanks to Ross Hill and Bob Carlson for identifying this wasp.

About Charley Eiseman

I am a freelance naturalist, endlessly fascinated by the interconnections of all the living and nonliving things around me. I am the lead author of Tracks & Sign of Insects and Other Invertebrates (Stackpole Books, 2010), and continue to collect photographs and information on this subject. These days I am especially drawn to galls, leaf mines, and other plant-insect interactions.
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6 Responses to First parasitoid of spring

  1. I’m so happy you started this blog, Charlie. All you need is to add a “subscribe” button on the side.

  2. Thanks for the suggestion, Connor… How do I add a “subscribe” button? Seems like it should be obvious, but I just looked around for a few minutes and couldn’t figure it out. I’ve also been wondering how I add tags.

  3. Corey Husic says:

    Hi Charley,

    This is a wonderful post and I look forward to reading more! I too recently started a blog. While my new blog is more of a “learn with me” journal, I hope you would take a look. <a href=";

    See you on BugGuide!

    • I like it! Since I got this macro lens, I’ve found myself looking under logs, bark, and leaf litter a lot when I’m not finding much to photograph out in the open–especially in the fall and early spring. There are always springtails, mites, etc. to be found, and it’s always a fun challenge to try and get decent shots of them. Congrats on the new US record!

  4. Pingback: Acorn Pip Galls | BugTracks

  5. Pingback: Big, Beautiful Parasitoids | BugTracks

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