a unique case of predator-prey role reversal

November 1, 2019 12:35 PM

Amphibians, such as frogs, typically prey on insects including ground beetles and their larvae. The Epomis larva has impressive double-hooked mandibles that look like they came right out of a horror movie. It waves them around along with its antennae until the movement attracts a hungry amphibian, which approaches quickly and tries to eat the larva. In a surprising turn of events, the larva is able to dodge the predator’s attack only to leap on the unsuspecting amphibian and sink its jaws into its flesh. These larvae begin by sucking blood from the wound and eventually consume the frog altogether.
posted by sciatrix (31 comments total)

I am really not easily disturbed by nature pictures, but there's something about the photo of the frog with the larva half out of its mouth and the caption "Hard to believe, but this toad is being eaten" that really puts me on the verge of a panic attack.

The idea that the bug has the toad by the tongue and will keep holding it

excuse me I need to step out for some fresh air
posted by bgribble at 12:50 PM on November 1, 2019 [8 favorites]

Thanks, I hate it
posted by Doleful Creature at 12:52 PM on November 1, 2019 [9 favorites]

Makes one especially appreciate being at the top of the local food chain.
posted by she's not there at 12:53 PM on November 1, 2019

From the article:

One common reaction that I get in response to this study is that it was “cruel”, involving poor helpless amphibians that were sacrificed in the name of science. Some people even go further to suggest that I am a sadistic scientist somehow enjoying this. It could not be farther from the truth: This is a natural phenomenon and Epomis beetles must kill and consume amphibians in order to exist. Nature is cruel. We tend to think of amphibians as cute and helpless animals, but from the insects’ perspective they are actually cold-blooded killers (pun intended), gulping every small creature in their path. Moreover, the reality of this study is even harsher: the amphibians would have still died even without me using them as food for Epomis, because the puddles they were found in as tadpoles were quickly drying out. As for myself, I cannot begin to describe the emotional stress I suffered during this research, just so I could bring Epomis’ fascinating biology to the spotlight. I love amphibians, and it was disheartening for me to watch them die so many times. Throughout the study I kept telling myself: “I am going to hell for this, no doubt about it”.

Adult Epomis feeding on frogs [YouTube]
posted by ryanshepard at 12:58 PM on November 1, 2019 [7 favorites]

Makes one especially appreciate being at the top of the local food chain.

Octavia Butler's SFF horror writing has used parasitism from nature to great effect in her depictions of aliens, memorably with bot flies.

I gotta say, staring at these guys I keep wondering how a really good horror writer could turn something like this relationship into a really, really good novel.
posted by sciatrix at 1:04 PM on November 1, 2019 [4 favorites]

Gil Wizen is an international treasure, even when describing nightmare fuel
posted by scruss at 1:14 PM on November 1, 2019

This feels like a metaphor, somehow...
posted by Naberius at 1:22 PM on November 1, 2019 [2 favorites]

Epomis would be a good name for a credit card company.
posted by vverse23 at 1:23 PM on November 1, 2019 [14 favorites]

I have (mercifully) forgotten the details, but there is a parasite which eats the tongue of a sea creature, and then takes the place of that tongue in the creature's mouth as the creature goes on living.
posted by jamjam at 1:25 PM on November 1, 2019 [6 favorites]

callout post for nature: it's bad sometimes
posted by poffin boffin at 1:36 PM on November 1, 2019 [8 favorites]

Most scientists believe that humans developed hands for tool use. However, a small but growing movement instead proposes that the primary evolutionary input was the ability to go "ew ew ew get it off get it off!"
posted by BeeDo at 1:41 PM on November 1, 2019 [18 favorites]

Thanks, I hate it
posted by Doleful Creature

Of course you would.
posted by sjswitzer at 1:42 PM on November 1, 2019 [3 favorites]

Cool beetle with an awesome revenge story attached.
posted by GoblinHoney at 1:47 PM on November 1, 2019

jamjam: That was my Halloween costume yesterday--Cymothoa exigua, the tongue eating louse! I got some onesie clownfish pajamas with a hood and made a stuffed version of one I'm quite proud of and put it on top of a pink hat. You can tell my coworker are very used to me and my telling them about creatures like that and the one that's the topic of this post (which I have already shared in the #random Slack channel) because nobody was all that surprised, though they haven't really been listening either because nobody got it without me showing them an illustrative picture.
posted by foxfirefey at 1:54 PM on November 1, 2019 [13 favorites]

did you have that picture readily available on your person for this specific reason y/n
posted by poffin boffin at 1:57 PM on November 1, 2019 [4 favorites]

Thanks, I love it. Please share all the predation horror stories.
posted by jeather at 1:58 PM on November 1, 2019

This is so cool. Creepy but cool. Thanks, sciatrix!
posted by Bella Donna at 1:59 PM on November 1, 2019

I picked this stock picture, because I felt like it was one of the least upsetting ones while still being pretty easy to see the critter in the mouth, and it was important for it to be a picture of a clownfish since that's the fish I was. This is also a really fun picture of clownfish with cymothoa but it was harder to show the fish big enough on a phone, because it's several of them in a row.
posted by foxfirefey at 2:00 PM on November 1, 2019 [1 favorite]

Adult Epomis feeding on frogs [YouTube]

Holy hell, ryanshepard. I thought the linked web page was pretty interesting, but that YouTube video is an intense viewing experience. The music, the foley work, the pacing, some of the surprise plot twists... it's all gorgeous and grotesque.
posted by painquale at 2:37 PM on November 1, 2019 [1 favorite]

I guess horror-story bug/spider-eating things are somewhat less horrible (not that I clicked on any links in this post because no way). There's that spore that grows out of the inside of an ant, and that wasp larva that eats its way out of spiders and things.

From the second link:

The wasp's way of life may seem like a pretty raw deal for the spider. But in fact this sort of behaviour is astonishingly common. The wasps that lay their eggs on the bodies of other animals may well be the most diverse group of animals on Earth. Nature, it seems, loves animals that play dirty.

Yay science. O_o
posted by Glinn at 2:52 PM on November 1, 2019 [5 favorites]

There was a period when I curated a small self-created pond (roof runoff collected in a depression in a big rock), in the woods North of Montreal, and I wanted to encourage the few "Amphibians, such as frogs", that showed up and applied for the job.

I tried all kinds of things, like dangling scraps of meat on strings to simulate live prey, but nothing worked until I tried four inch fishing bait earthworms.

Man, they went for those! Hilarious to watch the process, where they fed themselves worms with little hands, looking like frog business-men smoking cigars.

The population in my little rock-divot pond exploded as a result. Three generations in just one season! ... although the third generation might not have survived the next winter, being too immature to hibernate.
posted by StickyCarpet at 3:15 PM on November 1, 2019 [4 favorites]

To follow up on the Epomis video that ryanshepard posted: what in the world is up with this Planet TOOTOO youtube channel? I am transfixed by it.

The videos are horrifying and unflinching in a way that nature videos rarely are, the edits and cinematography are often gorgeous, and the videos are set to the most dramatic music and sound effects... but the video counts are so low!

This amazing but horrifying video of a cuckoo killing its nestmates has less than 150 views. This dramatic cicada transformation has 150 views. This fly depositing its eggs on a caterpillar has 39 views. This outstanding frog leap into a dragonfly has 200 views. And there are oodles of truly disgusting Epomis videos. Here are some Epomis larvae casually creeping up to a frog.

I feel like this is an undiscovered gem.
posted by painquale at 3:24 PM on November 1, 2019 [16 favorites]

Sticky Carpet, you should read the sci fi novel, Annihilation, by Jeff VanderMeer. I learned about it if from a FPP here.
posted by KleenexMakesaVeryGoodHat at 3:29 PM on November 1, 2019 [1 favorite]

Holy dang, painquale, I only watched the frog v. dragonfly one but I shall be recommending it.
posted by Glinn at 3:32 PM on November 1, 2019 [1 favorite]

vverse23: Epomis would be a good name for a credit card company.

Epomisterical?
posted by clawsoon at 5:55 PM on November 1, 2019 [4 favorites]

Wow! I just did a class on predator prey interactions, and this would been a great addition!
posted by dhruva at 7:40 PM on November 1, 2019 [1 favorite]

This amazing but horrifying video of a cuckoo killing its nestmates has less than 150 views.

I'd like to think this behavior is driven by thoughtless reflexes but some part of me is convinced that first-born cuckoo chicks are just filled with unfathomable hate.
posted by dephlogisticated at 8:30 PM on November 1, 2019 [3 favorites]

Most scientists believe that humans developed hands for tool use. However, a small but growing movement instead proposes that the primary evolutionary input was the ability to go "ew ew ew get it off get it off!"

Isn't social grooming, like, a huge deal among great apes? The evolutionary history of "get this tick off my back!!" is probably awfully deep
posted by BungaDunga at 8:37 PM on November 1, 2019

Isn't social grooming, like, a huge deal among great apes? The evolutionary history of "get this tick off my back!!" is probably awfully deep

Hey you, you the one who somehow gets ticks off my back. Let's go someplace private and start building your evolutionary legacy.
posted by otherchaz at 9:39 PM on November 1, 2019 [1 favorite]

Who's the predator anyway?
posted by sneebler at 8:48 AM on November 2, 2019

I was initially horrified to hear a scientist talking about bird-eating moths on NPR the other day, then relieved when he explained they don't literally eat them... until he went on to say what they actually do is drink their tears while the birds seem paralyzed with fear.
posted by Rhaomi at 1:45 PM on November 4, 2019 [2 favorites]