Epomis circumscriptus larva eating habits

[paassatt]

There is a species of Epomis beetle whose larva feeds exclusively on frogs and toads. Pretty interesting stuff. It coaxes the amphibian into attempting to eat it, but dodges its tongue and spears itself into the amphibian's underbelly. Here's a video of a larva literally eating a frog from the inside out. You can see the frog becoming more and more skinny, and, well...see for yourself. Video copyright- Gil Wizen
[YOUTUBE]0y1FPm5WNVc[/YOUTUBE]

 

[Galapoheros]

I had forgot about those, I remember seeing about 3 other videos, they were much better quality. I wonder if those vids are gone now. I can't remember if somebody posted them here or if I saw them on Youtube but I think they were posted here on the AB.

 

[TsmallV]

poor frog thats got to be the worst

 

[Bugs In Cyberspace]

That's really amazing. I saw a video of an adult ground beetle attacking and killing a frog a while back, but this is a new one for me. The whole ordeal is amazing. Think of all the prey that frogs consume, each meeting the same fate and yet this one somehow manages to live and turn the tables! It looked like the frog spit it up. Can anybody describe the process in words because the video seems to raise more questions than provide answers. Does the larva secrete something that cause the frog to vomit? Does the larva feed on the frog while inside? Was it feeding on it from the outside, later? I don't really get it.??

 

[goldbread]

That's really amazing. I saw a video of an adult ground beetle attacking and killing a frog a while back, but this is a new one for me. The whole ordeal is amazing. Think of all the prey that frogs consume, each meeting the same fate and yet this one somehow manages to live and turn the tables! It looked like the frog spit it up. Can anybody describe the process in words because the video seems to raise more questions than provide answers. Does the larva secrete something that cause the frog to vomit? Does the larva feed on the frog while inside? Was it feeding on it from the outside, later? I don't really get it.??

im not sure if the larvae secretes anything but what i am sure of is...the frog probably knew something was wrong when the larvae was biting it from the inside.
so it probably spit it out.
and usually when frogs and toads vomit things (at least from my experiences with amphibians in captivity) you can see their whole stomach come out of their mouths and they smear off all of their stomach contents with their fore limbs.
you can see in the video this toad didnt have any stomach left!!!!
or at least i think haha
<edit> looks like it was painful though...
i would like to know more on this freaky beetle as well

 

[Deroplatys]

I think they might enjoy their work a little too much to record it so many times.

 

[paassatt]

I think they might enjoy their work a little too much to record it so many times.

Can you explain what you mean? :?

 

[lizardminion]

Can you explain what you mean? :?

Think of it as... a new frog every video. You get the idea.

 

[paassatt]

Think of it as... a new frog every video. You get the idea.

I understand what you're saying, but Deroplatys' post insinuated that they were doing it merely to get enjoyment out of watching the frog die. I would disagree. People do research on animals all the time, but that doesn't necessarily mean they're doing it just for the "kicks" of watching an animal suffer. I recently read a paper published wherein they tested how different colors' wavelengths were discerned by a tarantula's eyes; the author removed the legs of the spider at the carapace and pinned the spider down with a needle to accomplish the test...does this mean that they "enjoyed their work a little too much"?

 

[wizentrop]

I was happy to find this discussion here and I will try to put some meaning into unclear things:
The Epomis larvae attract amphibians by displaying slight movements to mimic a suitable prey item for the amphibian. When the amphibian attacks, the larva responds quickly and attaches (by biting) to the nearest area on the amphibian's body. Usually it's the throat skin. In general, the larvae feed as ectoparasites, meaning that they hang onto the amphibian skin while sucking their body fluids. During this time the amphibian behaves normally (hunts for insects, jumps, swims) although a bit more sluggishly (actually exposing itself to other forms of predation...). After some time the amphibian is weakened and then the larva starts in active predation and literally eats the amphibian, killing it, and leaving behind only a few bones. At this stage the larvae will either molt to the next instar or lure another amphibian specimen.
In one particular case, which is documented in the video above, a green toad swallowed a larva before it managed to respond and attach. However, before being completely swallowed by the toad, the larva did manage to attach from the inside, to the inner wall of the mouth or deeper in. The toad was immediately affected, and tried repeatedly to eject the larvae. Eventually it failed and swallowed the larva, but I believe that the larva was still attached to the inner mouth/throat using its mandibles. This created a stimuli for the amphibian to regurgitate, since the larva was not entirely swallowed. It is unclear how the larva has survived for two hours inside the toad's stomach. It is possible that during its time in there it did some sucking and feeding, but I don't think the larva managed to cause much damage other than the internal injury caused by biting - after regurgitating the toad behaved normally and walked in the container as if nothing had happened. After the larva was regurgitated it re-attached itself to the toad again, this time in the throat area as expected, and started feeding in the typical manner. The toad was consumed and killed after a few hours.

I get criticized for this "evil" study many times. The catch here is that if I hadn't done this research no one would have known about this phenomenon of small larvae luring bigger amphibians to prey upon them, which has been hidden from the eyes of scientists for many years. It also has some important implications for conservation of amphibians populations. I love amphibians and I wasn't enjoying collecting the amphibians and putting them into the experiments for a slow death sentence. If you are interested in reading some "first-hand" descriptions of the research experience, you can find more info in the following link, courtesy of Jonathan Wojcik (warning - graphic content):
http://bogleech.com/bio-epomis.htm

Sorry for this long post. I plan to record this interaction again this spring in the field, and hope to produce better quality videos.

 

[wizentrop]

I sincerely apologize for bumping up such an old thread, but I recently posted some new footage of these beetles in case someone is interested -
http://gilwizen.com/epomis/