Epomis, Cymothoa, Hymenoepimecis : Halloween Horrors

In recognition that Halloween is almost upon us, we pay a visit to Nature’s dark side. A beetle, a crustacean and a wasp that do really pretty extraordinary things. But not, let’s be honest, things that you could really call ‘nice’. Predators and parasites that demonstrate just how surprising. and kind of merciless, the natural world can sometimes be …

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Despite what I said in the show, I’ve managed to keep the shownotes not too terribly gruesome. A little bit creepy, perhaps, but not horrible. So read on for photos, video, links to research papers and all the usual goodies …

So … horrors.


Here, a ‘lucky’ amphibian encounters an Epomis larva:

Photo by Gil Wizen. CC BY 4.0.

and here’s an adult Epomis with what’s left of another ‘lucky’ amphibian:

Photo by Gil Wizen. CC BY 3.0.

Now I did say in the episode I hadn’t quite settled on what I was going to put in these shownotes by way of video – but now I have! And I settled on a compromise: here’s one of the least gruesome (but still pretty amazing) videos of an Epomis vs. amphibian interaction you can find:

That is a small prey item by Epomis standards, and the video obviously doesn’t show the full process to its bitter end. You can find video that does easily enough by googling, but also in the first of these scientific papers which I humbly offer to those wanting more Epomis details:

Wizen and Gasith, 2011, PLOS one, An Unprecedented Role Reversal: Ground Beetle Larvae (Coleoptera: Carabidae) Lure Amphibians and Prey upon Them.

And here’s one from the same authors that’s got a bit more about how this all works out in the wild:

Wizen and Gasith, 2011, ZooKeys 100, Predation of amphibians by carabid beetles of the genus Epomis found in the central coastal plain of Israel.


Oh, look. That fish has a crustacean living in its mouth …

And here’s a better view of what it’s got in its mouth, the remarkable (is that the right word?) Cymothoa exigua:

You can access a PDF of one of the earliest detailed papers on Cymothoa exigua with a couple of clicks here:

Brusca and Gilligan, Copeia 1983(3):813, Tongue Replacement in a Marine Fish (Lutjanus guttatus) by a Parasitic Isopod (Crustacea: Isopoda).

And, as one example of several more recent studies that spell out just how much harm these parasites are doing to their fishy hosts:

Parker and Booth, 2013, Marine Biology 160(11), The tongue-replacing isopod Cymothoa borbonica reduces the growth of largespot pompano Trachinotus botla.


Note: In a stroke of comedic genius (genius, I say!) I totally mispronounced the original version of the spider’s name that I said was the one I could easily pronounce. Oh, how we laughed. Anyway, it’s not ‘Pleistoma’ or whatever I say, it’s ‘Plesiometa’. D’oh.

Awesomely detailed (but pretty readable and not too technical) paper that (as far as I know) provided the first really detailed description of what Hymenoepimecis argyraphaga was doing:

Eberhard, 2000, Journal of Hymenoptera Research, Vol 9(2), The natural history and behavior of Hymenoepimecis argyraphaga (Hymenoptera: Ichneumonidae) a parasitoid of Plesiometa argyra (Araneae: Tetragnathidae).

And another by the same author (be aware this one’s a direct link to the PDF):

Eberhard, 2003, Journal of Arachnology, 29(3), Under the Influence: Webs and Building Behavior of Plesiometa Argyra (ARANEAE, TETRAGNATHIDAE) when Parasitized by Hymenoepimecis argyraphaga (HYMENOPTERA, ICHNEUMONIDAE).


Opening & Closing Themes: Running Waters and Acoustic Meditation by Audionautix (Jason Shaw), from audionautix.com. CC BY 3.0.

Navajo Nights by Audionautix (Jason Shaw), from audionautix.com. CC BY 3.0

Ebow Song and Dead Waters by Rest You Sleeping Giant. CC BY 4.0.

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