Floppy Abdomen and/or Abdomen Collapse


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Active member
Sep 4, 2023
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Portland, OR
Hi everyone, as a few of you may know, I had 2 Chinese Mantises a couple of months back and one died due to what I suspected was abdomen-collapse syndrome, my other one is doing okay but has developed what I believe is floppy-abdomen syndrome after his 5th molt.
1. I've heard that tipping the enclosure so that all hanging surfaces are at an angle will help, I've done that, and I'm going to try to keep him upright during feeding. Is there anything else I can do to help him? I've heard that floppy-abdomen is often fatal so I want to act now before it gets worse.
2. is there a difference between floppy-abdomen and abdomen-collapse, and if there is, what is it? When the first one died I was pretty sure it was abdomen-collapse, but now I'm starting to think that it was something else. I've posted pictures of the one who died a few months ago and the one who has developed floppy-abdomen, any help is appreciated.
Mantis that died from possible abdomen-collapse:

Mantis with floppy abdomen:
The names "floppy abdomen" and "collapsed abdomen" are flexible - there's no official definition for this kind of thing. That first mantis seems to have starved to death - that kind of thinness is only possible if the gut is completely empty.

The second one though, that has what I usually see referred to as "collapsed abdomen." This happens in species like Tenodera which hold their abdomens straight and are not made to hang upside-down for the majority of their lives. Euchomenella and, I've heard, Heterochaeta can also develop this. The exact causes unknown but it's definitely related to hanging upside-down consistently. Tenodera is a grassland animal - in the wild they spend most of their time resting vertically or even dorsal-side-up, but in captivity they don't have the instinct to not take advantage of a convenient perch on a mesh lid. If many individuals are kept identically, they don't all develop the collapsed abdomen. This makes me think it's influenced by something else, like exceptionally large meals or a heavy abdomen soon after a molt.

Correcting the drooping abdomen involves changing their housing so they cannot hang upside-down. You can make a cone of wire and mesh and use that as a lid, or put them on a plant or series of sticks that don't touch the ceiling, in a large enclosure with a lid they have trouble gripping. Feed those animals less (still give them water consistently) so the abdomen is lighter and they can digest most of the food before being fed more.

In these pictures the abdomen is not as bad as it can be. If you keep feeding smaller prey (still substantial, not fruit flies) and keeping them from being upside-down constantly, they have a good chance to be normal next molt.
I've "cured" a chinese mantis of this before, I kept it in a fishbowl so it was forced to stay upright and made sure to feed it to give it structure to its abdomen and sure enough she molted to adulthood just fine! after about a week of keeping it upright and well fed the improvements were obvious. not sure if this is the optimal thing to do but it worked for me really well! best of luck.
Thank you so much for the advice, I am working on getting some enclosure modifications for him. I can't get a fishbowl but for now, I have ordered a mesh cube that I will orient to keep one corner at the top where I will hang several fake plants so that he has difficulty hanging upside down.
That first mantis seems to have starved to death - that kind of thinness is only possible if the gut is completely empty.
It does look like was starved and I suppose that is partly my fault as I anticipated a molt a little early and stopped feeding it too soon. The thing that still confuses me though, is that during the previous instar, I fed it regularly and after every feeding, its abdomen would get nice and plump. But then, several minutes after feeding, its abdomen would shrink back down to paper-thin as if I hadn't fed it at all. The odd part is that I didn't observe the food coming back out as fecal matter or vomit, it just looked like it vanished.
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