Pesky Parasitoids

A big “thank you” to my first 13 patrons! I’m almost done writing the main introductory chapter that I’ve been putting off dealing with for a few years now, and soon I’ll get to work trying to put together a reasonable summary of the various groups of wasps that parasitize leafminers… which reminded me of a couple of wasps I got to watch develop this year, so I thought I’d share the photos here.

On September 16 Julia and I participated in this year’s Berkshire BioBlitz in Great Barrington, MA, naturally focusing on the galls and leaf mines that no one else was going to look at. When we encountered some mines of nepticulid moths on black birch (Betula lenta) leaves, we were compelled to collect them and try to rear them out, because there is a bewildering array of similar mines on birches that still need some sorting out. As I was taking a backlit photograph of each mine that still contained a larva, I saw that this one had a problem:


Namely, it had an ectoparasitoid chomping on its back.


The following night, all that remained of the moth larva were its head capsule and (please correct me if I’m wrong) Malpighian tubules, and the wasp larva had begun to wander back down the mine channel.


It continued to work its way back until the next morning.


A day later, it had backed up just a little bit (you can faintly see its pointy posterior end crossing the moth larva’s frass line in the photo below), and its gut contents had visibly consolidated.


Another day later, it had finally pupated, depositing its shed skin and meconium (all of the accumulated waste products from its life as a larva) in a heap where the tip of its abdomen had been the day before.


Eight days after that, the adult wasp had chewed its way out of the leaf, leaving its pupal exuviae behind.


This is a eulophid wasp, very similar to this one that Christer Hansson identified as Pnigalio flavipes. That was before he examined more of my reared eulophids and decided that the whole genus Pnigalio is in serious need of revision because, for instance, males and females that clearly belong to the same species key out to different species using the existing keys.

I’ll save the other wasp rearing series for another day!

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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8 Responses to Pesky Parasitoids

  1. Hi Charley – I have tried 4 times to become a patron but Patreon does not seem to accept any of my credit cards nor my Paypal account. Maybe it is only for USA? I’m in Canada and it tells me I do not have a valid address – apparently because we have a postal code with 3 numbers and 3 letters contrary to your 5 digits zip code. Sorry – I have really tried!

    • Hi Gilles– Thanks for trying! The Canadian address shouldn’t be the problem, because one of my patrons lives in New Brunswick. You might try asking for help here; also I can probably work something out for people who want the leafminer book but can’t or don’t want to go through Patreon for whatever reason.

    • bcottam2014 says:

      I’m from Canada too and just managed to successfully sign up on Patreon. The sign-up page assumes a USA address, but if you click on ‘United States’ then a dialogue box opens up, from which you can choose Canada. The box then allows our postal code to be entered. Hope this helps!

  2. This is so interesting, Charley, and I’m always impressed by your patience and the level of detail in your observations.

  3. Erin Hilley says:

    I love following these convoluted stories. Thank you.

  4. John van der Linden says:

    Excellent in an inexpressible sort of way…I’m delighted. Thank you as always for sharing, and congratulations on your upcoming class offerings and developments with the book.

  5. Pingback: Pesky Parasitoids, Part 2 | BugTracks

  6. All this stuff is so fascinating. There is so much life all around us we have no idea about. Thanks for sharing.

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