Eastern Herc suddenly shrank?

GelGelada

GelGelada

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I had one of my Eastern Hercules suddenly almost HALF in size so I'm a little worried. This is right after I changed out their substrate for new stuff and added oak chunks. Substrate is a mix of old flake, organic mulch and oak leaves and chunks.

Should I be worried? I got these around October of 2018 from Peter and while they are are still very lively, I would not think they'd shrink that much on the same food they have had for at least three months now. I think one may have a blockage from the oak, but I am not sure what I can do about it? The one on the RIGHT is the one I'm worried about. LEFT has not shrank and is the same size as it appeared two weeks ago when I checked them.

Edit: While I got them in October of last year, they were not L1. They were nearing L2, so the exact age is somewhere in the seven month mark, maybe a bit more.

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I've seen this sort of thing happen to D. tityus larvae (as well as those of other species of Dynastinae) occasionally, but unfortunately, I have no idea what causes it.  It's probably not related to your substrate change, though.  One possibility is that the larva has suffered a catastrophic loss of its vital, symbiotic gut fauna for some reason, but that's only a guess.  Is it just that one larva that's having a problem?  Are the others all normal?

 
All the others seem normal, yes. If it's gut flora, I thankfully have some poop in a jar which I saved for this very sort of emergency. I ordered more oak flake to be safe, as the batch I have started still has a long way to go.

The only thing I can think is that I maybe baked the last batch of substrate for too long and killed off all the nice stuff, so this particular grub didn't have enough gut bacteria? (I didn't bake my substrate in the past, but now that it's summer I have to do so to kill off the gnats which have suddenly infested some of my jars. It's helped a lot with those outbreaks). That's all I can think of. Now that you mention this, I'm gonna look for that jar right now and see if making "tea" with that and adding it to it's substrate might help. Right now it's in a smaller container so I can monitor it, as I didn't even notice this sudden change until today when I decided to check if they had eaten their oak chunks (which, they had indeed eaten a significant portion).

Once I get more pure flake and not a mix, I'm just going to stop baking entirely because this sort of thing has me super stressed out because my Eastern Hercules have had the least amount of issues of all my beetles (ox beetles are another story; those were touch and go for a while before they all "stabilized" and I stopped having strange, unexplained deaths).

 
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Happened to me a few times before. Always mix a bit of the old sub with the new so the larvae isn’t totally shocked. See if they will eat a piece of soft dog food. If the larvae is on the surface put the food near it. If it is underground, get a pencil and create an appropriate sized hole in the substrate leading to the tunnel. Drop the food down into the tunnel and see if the larvae will take it. Make sure to remove the food after a day or so if the larvae doesn’t eat it. 

 
I don't have any dog food, only cat food. Last time I tried dog food, none of them would eat it so I haven't kept any around. However, it may have been because it was a grain-free food marketed for elderly dogs with upset stomachs and made mostly of salmon (it was my roommate's dog, but she's since moved). I have mediocre cat food and betta flakes, which I use for supplementing my millipedes. Either of those okay?

As for the substrate, I always keep a handful of the old stuff in or more unless it gets totally infested with crawlies, but this time that didn't happen which is why I'm concerned. Had I done a full change, yeah- that would make more sense.

 
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Yeeeah... checked it at 1 PM today and it's at the top of the substrate and it didn't touch the cat food. Dunno what to do at this point, so I'm just going to leave it be and wait. Poor thing. I've only got three Eastern Hercules so this is a hard blow to me.

 
Shouldn't be? It was all made about two months ago (well, not quite two- I had it written down somewhere but I'm not sure where the slip has gone), as I do my substrate in small batches because I don't have much storage (barely two "shoe boxes" full at any given time, because I only have a handful of larva). Took the larva still in it's container out in the sun this morning and it went back down into the sub and hasn't come out since, so it's still responsive to light and tries to stay away from it. It appeared to be eating on the surface prior to this so I'm hoping it's just a gut issue. Ordering fresh sub just to be sure for this guy because clearly something isn't right with this particular larva. The rest of all my larva are fine; no strange changes but I only looked through the sides of their jars and tubs.

If longer than a 1-2 months for sub storage isn't okay, I'm not sure what to do about it. I no longer have a cooler to freeze it, if that does anything to help.

 
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That's what I'm thinking, but I find it a bit unusual given the age of the larva? I would expect this from something a lot younger and not something which has eaten mostly the same food for months now. Oh well. We'll see if the "poop" treatment helps in a week. I'll be ecstatic if it does... I think I'll just keep this one in my laundry room where it's consistently warm and muggy (it's not enough to make you sweat) because my house is rather cold since the summer heat has been rolling around. That might help it's appetite I think.

 
Wait-! I think I know what may have caused this. The wood chunks. It didn't even occur to me. The wood I gave these was from a different batch than the baggie of wood chunks I have used from last year. From a tub of dirt and leaves I have in my garage which I use for my other insects. Maybe something in that has made it sick? The other grubs got that wood too but haven't shown any similar signs (yet).

 
Update: Poop treatment and completely new sub appears to have cured this little fellow. They have put on weight again and look nice and plump again. Other grubs still on the old sub and appear fine, so I think this one just had a gut issue that was fixed by introducing the poop from a healthy beetle and new fermented sub.

 
GelGelada said:
Update: Poop treatment and completely new sub appears to have cured this little fellow. They have put on weight again and look nice and plump again. Other grubs still on the old sub and appear fine, so I think this one just had a gut issue that was fixed by introducing the poop from a healthy beetle and new fermented sub.
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Ahh that's happy!  I was fearing for the worst as I read this but it's nice this turned out good!  :D

 
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