Have you ever raised/bred Tenebrio, if so, why did you decide on Tenebrio?

Hello everyone!

By now, those of you who have read most or all of my topics/posts or whatever you wish to call them, you probably have noticed that the greater majority of them are either about, or mention insects. Specifically beetles. And most of my Posts that I will be creating over time are probably going to be insect/beetle-related topics because Coleoptera is what I work with every day, and I feel very comfortable working with them. (Sorry to anyone who likes Hymentoptera more, but the only Hymenopterans that I will go near are Formicidae(ants) and let’s put it this way. Bald-faced Hornets do not like me(Washington trip a few years ago, and this past November too) and I no longer like to be anywhere remotely near them, or any other larger Hymenopterans that can do harm.)

Anyway, this one is asking specifically, have any of you ever raised and/or bred Tenebrio (mealworms) at any point in your life? If so, do you have any tips, suggestions, or warnings that you would like to give to anyone else who is raising/breeding them to help them (hopefully!) have a higher chance of success?

My first one is a warning. DO NOT, EVER, accidentally mix your Tenebrio larvae with your Zophobas larvae! It will end in dead and decimated Tenebrio larvae, and this is only a good thing if you were trying to feed the Zophobas. Suggestion, feed the Zophobas larvae any dead or dying Tenebrio larvae that you have, but only if they are still soft, and bendy, if they are dried up and hardened, then they will not eat them. Shoot, I went off topic again.

Well, I hope this helps anyone who is raising them, and any Tenebrio breeders who also use iNat!
Good luck, I also can’t wait to hear different ideas etc. because I have mainly been feeding mine old bread, potatoes, and oats.
Peace out!


April 23, 2021

  • Contrary to popular belief, adults can fly (they do not have fused elytra). They rarely do so though. Flight seems to be induced by environmental stress.
  • If larvae are very small they tend to bore holes in the fruit and vegs. Extrication is a massive pain, I suggest only using thin vegetables like lettuce until they become large.
  • Keep the substrate dry and extremely well ventilated at all costs (mere pinholes will not do).
  • Larvae tend to drag fruits and vegetables underground, causing mold and accumulation of uneaten food.
  • They can also be kept in dry isopod-style leaflitter substrate; grains are not strictly needed.

As kids we fed mealworms to a variety of reptiles and birds that we raised. The system we used (which i occassionally resort to now and again) was to use:
Old broiling pans about half filled w rolled oats.
Slices of raw potatoes scattered on top of the oats. As they became dried up we would replace w fresh slices.
Old, metal framed window screens resting on top of the pans to keep the mealworms in and other things out.

I remember three such pans in our basement growing up, that produced a constant supply of mealworm larvae.

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When I worked at a couple local nature centers, we kept colonies of mealworms going to feed other animals and to use in insect programs when we wanted to show life stages (larva, pupa, adult). We kept them in dish pans or kitty litter pans and used oatmeal and bran as bedding. We just left them on the floor under the tables or racks. Much like @trickman describes, we put slices of potato on top for food and moisture. We usually covered the bins with a screen.

I keep some fresh mealworms around now to feed backyard birds, but I just buy them in canisters. I was advised to feed them carrots instead of potatoes and the carrots do seem less prone to getting moldy than the potatoes.

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Yesterday I just gave them my leftover burnt sandwich crust, and they have devoured it. Burnt bits and all.

W😄w! I guess they are grain eaters after all.

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For sure!

I gave them more bread today and they currently only have a small section of crust left. This batch doesn’t seem to care much for the carrots, compared to the previous generation of them at least.

I’ll try seeing if they will go for different types of potatoes, then peanuts.

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I had thought the idea about using potatoes and carrots was to provide some moisture, too. But, now that I think about it, I’m not sure anyone ever told me that - it could just be my assumption.

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Who knows?

Where do you get yours from?


The local bird seed store carries live and dried meal worms. The brand is Rainbow Mealworms. I could buy them online in bulk (at Rainbow’s website) at less expense; but we like supporting the local store.

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I’ve never heard of that, but I’ll have to check it out. Our chickens really like the larvae with the most energy and movement, so the ones that move a lot are better for them, or else they can escape because the chicks don’t see them.

I asked the company, Rainbow Mealworms, if there could be any likelihood of them escaping and multiplying in the yard if I just set the live worms on the ground instead of a feeder. The rep said, no. Now that I re-read the answer, I see the veggies are indeed intended for moisture:

Mealworms rely on grain for their food and a water source like cactus or vegetation like carrots and potatoes.

In the wild, if they can find a grain storage area (like for chickens or birds) they will live very happily (but not as far as the humans are concerned!).

They can also live under decaying wood like logs and in animal dens eating decaying leaves and grasses, but the protein content generally isn’t high enough and they will not survive long term.

They need a warm habitat of 75 to 85° to thrive and breed.

It is difficult to find the right conditions for them to thrive in the wild as most climates are either too hot, too cold and don’t have adequate grain/protein sources for them to breed and thrive.


Gillian Spence Rainbow Mealworms, Inc…
Customer Support
email: support@rainbowmealworms.net
Phone: (310) 635-1494 Text: (480) 409-2347
Website: www.rainbowmealworms.net

Actually, I have found that several escapee mealworms have made their new homes in my backyard, frontyard, and garage. So, unless these are GMO, I think that there is still a chance of them surviving and multiplying.


Good to know…

I provide these to the birds in a two-inch deep feeder suspended from a hook in the patio. There seems to be little chance they can get out into the “wild” and survive well in the patio.

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I’ve checked out the site, and I think that I may need to try it out sometime, seems usable. : )

Buffalo Beetles

Buffalo Beetles are tiny and cute!
Close up of beetle which is only 1/4" long
I like this part too!

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Sorry, I didn’t see your reply when I finished typing. My bad.

I wonder if the local birds here would go for them…
I may need to try that as well!
Thank you for the Tenebrio info, link, and ideas @teellbee I appreciate it!


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I rescued a bunch (300) from a petshop, and kept them in a huge tub full of oats, and I would put carrots in there and they would just disappear! :rofl:

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I think if the new owners of that house lift up the carpets, they may have a rather unpleasant shock! (They started breeding under the carpet)


Then where did they come from originally? They must have once been wild.

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