Question on Moisture / Condensation in Larvae Housing

[PowerHobo]

I'm currently attempting to raise my first rhino grubs, and it's my first time with anything more complicated than darklings.

I gave all of my substrate a squeeze test to make sure that it was compactible, but that no liquid dripped out, it even actually seemed a little dry to me, but since it was able to hold shape I went with it.

I've got the larvae in 8oz containers right now, filled pretty much to the brim with substrate, and I've got about 20 holes punched into each lid with a heated thumb tack, and I'm still seeing regular condensation. Since I've read that there should really only be about 4 or 5 air holes per container I'm wondering if something else in my setup is to blame.

The room they're in is typically around 78-80f (25-26c), though it dips at night to around 75f, and morning is when I see the most condensation, though every now and then it's in the middle of the day as well when the room is at its warmest. About half the time if I check on the containers they're free of condensation. I'm in the middle of the desert, and it's typically very dry here; I'm not sure if that might have anything to do with it.

Both of my M. punctulatus were hanging out partially burrowed at the top of their containers this morning, and I just want to make sure they're not being smothered by excess moisture. I think they're L2 (I don't know enough to be certain), and they seem a little large for 8oz containers to me anyway, but I'm not sure if being short on space would cause the behavior. My D. tityus are both still buried to the bottom.

If I'm being way too concerned about something that is somewhat trivial, please feel free to tell me to stop being a total noob.

 

[arizonablue]

This happens with mine all the time. (Also in the desert, hello from Tucson!) It's not a problem, it's just caused by the low humidity in your house versus the high humidity in the containers. You can prevent it somewhat by putting the containers in a place with minimal airflow (my pantry works great for this) but as long as you're monitoring the moisture content in the substrate, the condensation isn't a problem.

 

[Garin]

Yes, agree with Arizonablue, condensation on the containers is normal. In fact, when my containers don't have condensation, I usually find out that they are too dry.

As far as size, you may not need to do it now but might as well just put them in 32 oz containers. Less substrate changes, more room for growth, etc. You can use that same size all the way to adulthood. 8 oz seems a little shallow.

 

[PowerHobo]

Thank you both very much! This is a relief, because just as an experiment I punched 30 holes in a new lid with a larger-gauge pin (big enough to let undesirable pests in), and I still had considerable condensation this morning. I've switched the lid back; I know with as dry as the Las Vegas air is I'm likely going to have to be more active with my substrate in general.

Related question, as I've seen some conflicting information: should there be a bit of an air gap between the top of the substrate and the lid of the container (1/2" or so)? I've seen so many where the lid is directly pressing on the substrate, and that seems like that wouldn't give much in the way of airflow, though I'm not sure if that's kind of the point.

... might as well just put them in 32 oz containers... 8 oz seems a little shallow.

I agree; the fact that I can always find the M. punctulatus from the outside of the container doesn't seem like they have enough room. I found some 16oz containers I had for unrelated purposes that I'm going to transfer them to for now, and I'll pick up some 32oz with screw lids come payday. I've got some oak flake on the way from BiC, so I would've been changing them out anyway.

 

[Garin]

You probably know this but you don't need screw on lids. The regular deli containers you get from the deli with snap on lids is totally fine. Usually you can find some 32 oz containers laying around somewhere. You can even use peanut butter jars, pickles, whatever. Just clean it good. I only mention this because you mentioned being on a budget and it's fun to find ways to do things for as cheap as possible. If you start telling your neighbors to keep all their old containers you'll soon have more containers than you'll ever need.

As far as space between the lid and substrate, that's a good question. I have always left a space and it seems totally fine and I know plenty of more experience beetle breeders that leave a space and it's fine as well. I have a friend that leaves an extremely small space in order to avoid reproduction of fungus gnats. He was telling me that if the fungus gnats don't have room to fly, they won't be able to mate so it keeps the fungus gnat population in control. He has had no problems with the little or no space between the lid with his larvae so I'm assuming that either works. However, maybe some more advanced breeders can share their experience.

Oh, before you start worrying about fungus gnats. Some people get them, some people don't, depends on your area, time of year, etc. If you don't have them, I would not worry about it now. They don't really hurt the larvae but they are a nuisance in the house.

 

[arizonablue]

I leave a space between the sub and the lid. I try not to remove pupa unless it looks like there might be a problem (mites, mold, etc) and leaving a space makes it really easy to tell when your beetle is out and about and ready for a proper tank. If you're going to be removing them from the pupal cell, though, a space isn't necessary.

P.S. If you do end up with fungus gnats, a quick and easy fix is to pitch the top inch of sub and replace it with fresh, or just remove the grub for a minute and mix up the substrate really well. Gnats reproduce in the top layer of soil, so discarding it will remove the eggs and turning the soil over will leave any freshly hatched gnats stuck in the soil and unable to fly or mate.

 

[Garin]

I leave a space between the sub and the lid. I try not to remove pupa unless it looks like there might be a problem (mites, mold, etc) and leaving a space makes it really easy to tell when your beetle is out and about and ready for a proper tank. If you're going to be removing them from the pupal cell, though, a space isn't necessary.

P.S. If you do end up with fungus gnats, a quick and easy fix is to pitch the top inch of sub and replace it with fresh, or just remove the grub for a minute and mix up the substrate really well. Gnats reproduce in the top layer of soil, so discarding it will remove the eggs and turning the soil over will leave any freshly hatched gnats stuck in the soil and unable to fly or mate.

wow, great tip on fungus gnats!

 

[Stardawg]

let it dry a little

 

[PowerHobo]

You probably know this but you don't need screw on lids. The regular deli containers you get from the deli with snap on lids is totally fine. ...

I'm only on a self-imposed "beetle budget"

I know myself enough to know that unless I set a limit on my hobby-related spending per pay period I'll suddenly find myself short on funds because of impulse buying (it was pretty hard not to buy as many D. granti as possible from BiC in one sitting). I know the snap lids are fine, but I have a history of dropping things, and a screw lid just seems like an easy proactive fix.

... and leaving a space makes it really easy to tell when your beetle is out and about and ready for a proper tank. If you're going to be removing them from the pupal cell, though, a space isn't necessary.

P.S. If you do end up with fungus gnats, a quick and easy fix is to pitch the top inch of sub and replace it with fresh, or just remove the grub for a minute and mix up the substrate really well. Gnats reproduce in the top layer of soil, so discarding it will remove the eggs and turning the soil over will leave any freshly hatched gnats stuck in the soil and unable to fly or mate.

That is a very handy tip on the gnats, and one that I'm sure will come in handy, since my adults have a mesh screen on their tank (for now), so if gnats are going to appear anywhere, it's surely there.

I'm not confident enough to go disrupting pupal cells, so it sounds like a bit of an air gap may be a good idea.

Thank you, guys!