View Full Version: Mealworms

Fishpondinfo > Insects and Arachnids > Mealworms

Title: Mealworms
Description: ?

firstgradeteacher - February 15, 2006 02:04 PM (GMT)

I just received a huge shipment of huge mealworms for my grade level to use with our students to study the metamporphosis.

We tried to maintain a habitat from last year, but we just didn't have enough large larvae at the right time of year to study in 10 first grade classrooms

So I ordered these through a garden shop nearby. I don't know if the bio supply co has been sending me a different variety in the last years, but these seem HUGE. They came refrigerated and seem very healthy.

Can anyone tell me anything about this? I checked to make sure they weren't altered to not pupate and that they WILL become beetles - but why are they SO big?

I am wondering how quickly they will pupate - does their size mean they are on their last molt and will change soon? Or are they different than the smaller ones I am used to from the bio supply co we've always ordered from?

Any mealworm expert advice and input would be helpful! Thanks!


reptileguy2727 - February 15, 2006 02:41 PM (GMT)
its probably just a different species of beetle than you usually get. other than that its hard to say. do you know the scientific name of the species you got?

Robyn - February 15, 2006 05:12 PM (GMT)
There are regular mealworms, giant mealworms, and king mealworms. The first two are the same species but the giant ones have been altered somehow to make them grow larger. You may have those. See my page at for photos of each kind (I notice the photo doesn't have great color though).
The larger ones will probably pupate soon if brought to room temperature and fed well. If they are king mealworms (which are huge and another species), they take a long time to pupate. If you can post a photo of them, I may be able to tell you more.

firstgradeteacher - February 15, 2006 06:08 PM (GMT)
I will see what I can do about a photo... but that will have to wait until at least tomorrow since I am at home today with a sick toddler...

I think I read that King Mealworms cannot survive in the refridgerator. Is that true? I know that these guys do fine in the fridge... they seem to be thriving in cornmeal with veggies.

I also read about the Giant Mealworms, and I called to make sure they weren't genetically altered to not pupate... yikes! That would've been bad for a life cycle unit in first grade!

Thanks for your help... I don't know the scientific name since they came in a huge cloth bag with no label... I guess maybe I will try to call them back and look into it...

Thanks again...


first grade teacher - February 15, 2006 06:13 PM (GMT)
I did scour your mealworm page yesterday, but looking at your photo again, they do resemble the size I think of the giant mealworm you have in the photo, they are nice and fat like that, but not dark brown like the Kings, and not skinny like the regulars... do you know if breeders have a way of fattening them up without altering their metamorphic cycle?

(Thanks again, I really appreciate your helpful page... it was a great resource for me)


Robyn - February 16, 2006 06:16 PM (GMT)
My giant mealworms do pupate and become beetles. Whatever alteration they incurred does not stop them from reproducing. The pupae and adult beetles are only slightly bigger than the regular ones. I'm not sure if they're actually the same species or not but my regular and giant mealworms do intermingle and probably interbreed. King mealworms will die in the refrigerator. Regular mealworms do okay in the fridge and sometimes even pupate in there. I keep my regular and giant mealworms at room temperature and active, and they pupate pretty quickly (a week or less). Because of that, I also feed the immobile pupae to my chickens since I have too many. My hedgehog eats the larvae and adult beetles. The king mealworms go a LONG time before pupating. I feed those to my 3' sailfin lizard only.

firstgradeteacher - February 18, 2006 02:34 PM (GMT)
I hope it's okay to post this link to photos of my mealworms...
I wasn't sure how to do the image loading...

My mealworms

Do you have any idea why they all stay on the top of the corn meal and don't seem to burrow? Is it because they are full grown? These mealies are mystifyin' me this year!!! :blink:

Robyn - February 19, 2006 02:49 AM (GMT)
Those are the so-called "giant" mealworms. They look ready to pupate unless they were altered in some way to be huge and slow to pupate. They may be on the surface of the meal because they're not hungry, need oxygen, and/or want to pupate. They are certainly big! I've had some that size but not all of the ones I buy as "giant" get that big.

firstgradeteacher - February 22, 2006 02:25 PM (GMT)
Thanks for all of your advice!

Okay, one more question... have your giants been able to reproduce after becoming beetles? I am hearing from a few sources that Giants are not able to reproduce due to the hormones they were fed...

Update: :) The Giant Mealies are currently slowing WAY down, have chosen spots in their specially folded newspaper, and many are starting to curl into c shapes - so hopefully we'll start seeing pupae anyday now, right?

Crossing my fingers for pupation :)


Robyn - February 22, 2006 04:29 PM (GMT)
Yes, they curl up right before they shed and turn into pupae.

Since I mix my adult regular and giant mealworm beetles together, I don't know for sure if they can produce viable eggs that hatch. But, they certainly do pupate and turn into beetles. I have noticed that some of the mealworms that I grow out from eggs that my mealworm beetles laid do seem to be larger than regular mealworms so that I get a mix of regular and closer to giant mealworms in the final batch once they're ready to join the other larger larvae. That would seem to indicate that they are reproducing along with the regular-sized mealworms.

firstgradeteacher - June 2, 2006 10:40 PM (GMT)
Just thought I'd update you all on the culture, I did mix my regulars and my GIANTS together after they pupated, and my culture is now RIDDLED with tiny larva... another teacher only had the GIANTS and also has tons of babies... so I guess they were just some kinda giant mealworms and not the genetically altered variety... thanks again for all of your input... it was all very helpful!

Hosted for free by zIFBoards