Giant Mealworms

Discussion in 'Feeder Forum' started by Domino, Oct 13, 2009.

  1. Domino Embryo

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    I bought some giant mealworms a few days ago, because my leopard gecko doesnt seem interested in eating regular mealworms, or silkworms, because he finds them too big. The giant mealworms i have are much smaller then the regular mealworms. Last night, he ate about 12 of them, so I was really excited, I finally found something he likes. Today I have read that they have chemicals in them, and I am just trying to find out if they are safe for my leo.

  2. Shanna66 Well-Known Member

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    i refuse to feed them to any of my animals because of those horomones. when i was new to keeping leos i fed some to ethen when she was younger, it messed with her system and she refused to eat for a week after that and to this day will not touch any sort of mealworm.
  3. LittleMick Embryo

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    I have never had any problems with Mealworms, in fact Elle has a diet of hlaf cricks and hlaf mealies. That's the only thing they sell at my local RC, I am looking for other sources for something like silk worms and such just to expand her diet. But I was just reading in another post about feeders and I need to find out more about Giant Mealies, something bad about them.
  4. jayhawkbruce Embryo

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    Would you mind posting this information that you read about "chemicals" in the super worms? I'd like to read it for myself before reaching any conclusions as to it's validity.
  5. JEFFREH Administrator

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    There seems to be some misunderstanding here, keep in mind guys, superworms and mealworms are two COMPLETELY different species of insect.

    Mealworms (Tenebrio molitor) are safe to feed, although not particularly the most nutritious feeder out there. The problem comes with the "Giant Mealworms." These are indeed mealworms that are typically treated with growth hormone. Do a quick google search, its not hard at all to find plenty of info about it. Here's a direct quote from

    "Giant mealworms are simply common mealworms that have been treated with an insect growth hormone to discourage them from morphing into beetles, thus they grow significantly larger. Some will morph into beetles, however they are sterile. Therefore, giant mealworms grow twice the size and definitely much fatter than a standard common mealworm."

    Many feeder companies that sell Giant mealies specifically state NOT to feed them to pets. These are usually just worms that are meant to be used for fishing bait, or for similar purposes.

    Superworms (Zophobas morio) are a different species from mealies. They are safe to feed, and slightly more nutricious than mealworms (also a lot more active and visually stimulating). Difference is that superworms grow larger naturally, live longer, require specific set-ups for morphing into beatles, and cannot be refrigerated because they are a tropical species.

    Other great feeders include silkworms and various species of feeder roaches like blaptica dubia, discoid roaches, and the turkistan roach. Phoenix worms are also good (although very small and pricey) and so are hornworms. Please do your research before feeding anything though, because some feeders like hornworms require special care to be able to feed. Hornworms from your backyard are extremely TOXIC to feed, and can only be fed from captive bred suppliers when fed a special, reptile safe chow.

    To be perfectly honest with you, I discourage feeding mealworms. They have a terrible meat to shell ratio, low nutritional value, and pretty much dont move at all. Sure some animals gobble them up readily, but variety is key to proper nutrition in any animal/reptile.
  6. LittleMick Embryo

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    Don't worry JEFFREH, I understood, lol. BUT.... thanks for that detailed info though, I had already heard about the Giant Mealies but I din't know exactly what the issues were, and I have kept meaning to post for other sources of feeders someone had already posted a list of feeders but I can't for the lilfe of me find the post., I had heard about Silk worms and Super worms, but you have just put the missing ones on the list, I know for a fact my local RC only does Cricks, Locusts, Mealies and Waxies, so I def need to look for another source.
  7. jayhawkbruce Embryo

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    There is absolutely nothing wrong with feeding regular mealworms to leopard geckos, or any animal that eats insects for that matter. I fed my leos meal worms for about 6 months straight at one point, and nothing else. For the last year that I had my leos, I fed them a mix of supers and crickets, but the one common thread among everything that I fed my leos was that the prey was PROPERLY gut loaded. Simply feeding crickets calcium water gel is not properly gut loading them. I preferred Fluker's Orange Cube. The stuff is great and it serves as a water source, although I offered a separate water source to my crickets on top of the orange cube. Best of luck.
  8. JEFFREH Administrator

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    Actually, thats incorrect. There are lizards than cannot be fed mealworms due to impaction issues. Young bearded dragons for example cannot handle mealworms as well as some geckos due to the way their digestive tract is set up. The undigestable parts of the exoskeleton essentially act as a blockage where the tract empties into the intestine, creating an impaction case. Mealworms are NEVER recommended as feeders for beardies.

    Yes, they are fed and have solely been fed to leos for years and leopard geckos have survived to be 15-20+ on a diet of solely mealworms. But has anyone ever tested their life expectancy on a more nutritious feeder like silkworms? It can't be done yet...

    I'm not saying they are a bad feeder, but just look at them and the nutritional comparisons to other feeder insects. The numbers don't lie, they are nutritionally inferior to many other available insects, and with a hard chitinous exoskeleton to boot...I don't prefer to feed them to any of my herps. Yes, they are widely available, easy to breed, cheap, but they are also just a shell with a small gap that can be filled with a small amount of gutload.

    Variety is key to any animal's well-being. I don't think anyone can deny that. In my opinion, mealworms are right down with waxworms as an occasional treat to be fed to herps. But that is just my own opinion, because many have been successful feeding only mealies to their reptiles (but once again, the nutritional numbers don't lie).

    Finally, Flukers is TERRIBLE. I highly discourage buying any Flukers product.

    "David and Howard Fluker, though, intend to turn their exotic pets (some of which sell for $300 or more) into animals with a brand identity, think the Coca-Cola of lizards."....... Sadly, it appears the Fluker brother do not understand that animals are not a disposable product. When the animals die, their customers cannot just dump it down a drain and pop the top on the next one in the refrigerator. The Fluker brothers may be able to dismiss all the dead animals they are responsible for, but the people who bought them don't - and won't." -Cheri Smith

    Read this:

    It will change your mind about buying any reptiles or related products from Fluker Farms.

    I hope it doesn't sound like I'm attacking you, I'm really just sharing my input and experiences and I just want to see the best quality of life come out of anyone's pets. =)
  9. jayhawkbruce Embryo

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    Didn't take it as an attack at all. Mealies will kill a baby beardie, huh? I've never heard that myself, but you learn something new every day (if you pay attention!).
  10. JEFFREH Administrator

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    Unfortunately they can =( I haven't seen an actual necropsy yet, but over the years I have seen about a dozen forum users on various sites complain of impaction and death in their dragons while being fed mealies and are in an otherwise ideal environment.

    It's really pretty tragic because many breeders and pet stores will commonly recommend them as a staple feeder for dragons and then results can be devastating. It's sort of like keeping herps on calci-sand or playing the lottery I guess, most of the time no problems will result, but there is a chance that something terrible could happen (and terrible things have happened to beardies). My vet advises not feeding young dragons mealies, and so do many reputable breeders out there. Typically it's not even recommend to feed superworms who have a slightly better meat/shell ratio until the dragon is a certain size or age.

    I recalled reading the article by Cheri on acidpohilus recently and she mentioned mealworm trouble and the product helping with it. Although the basking temperature did play a role in the inability to digest, they can still cause loads of trouble even to healthy beardies who are kept in a proper environment. I'm sure it has to do with both the way their digestive system is set up (as I mentioned earlier) and the fact that young dragons will consume absurd quantities of food. Mine would put away anywhere from 50-75 appropriately sized crickets a day, so that many mealworms with their chitinous shell would just seem like an impaction waiting to happen.

    "Just recently, I had a Bearded Dragon that I now believe was suffering from a mealworm impaction that was compounded by a misunderstanding about the temperature readings on the basking site." - Cheri Smith (from the acidophiliz+ article)

    From what I have come across though, it seems that this problem is pretty much focused to just Bearded Dragons. Not saying that it couldn't affect other herps, but there has not been a single problem ever documented to my knowledge of feeding leopard geckos mealworms.

    And back to the topic originally posted just for emphasis =) Mealworms and superworms are both acceptable to feed herps, but Giant mealworms are not recommenced due to the growth hormone they are given.

    EDIT: Decided to include this a few days after the fact, another quote from Cheri regarding mealworms as unacceptable feeders for bearded dragons:

    "This will probably shock some people, but as more studies are done we are learning more, our views or understanding of how food contents interact increase and we have to change our thinking. These are not from my studies, but others that I used to do my own study on feeder contents utilized by bearded dragons (what a beardie can eat and use in their body is different from what say a chameleon can) Remember when I say something like mealworms will impact a 2 month old dragons, that does not mean it will impact a hatchling gecko that is 1/2 the size. There are digestive differences that come into play between the two species and make it so the gecko that is 1/2 the size can actually digest something better than a larger beardie. Its physical and has nothing to do with the size difference of the two. Baby dragons have a short digestive tract and paper thin lining in the intestinal walls. They simple can not handle the amount of chitin, especially if other husbandry lacks anything, such as proper temps or poor substrate they may ingest" - Cheri Smith
  11. jayhawkbruce Embryo

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    Sounds good, thanks for the info about beardies. As to the hormone given mealies, I imagine they just give it to them in a gas and it is absorbed though their exoskelton. Otherwise I can't see how it would be cost effective for the price that mealworms go for even if it is administered in their food. Any thoughts/knowledge on how the hormones are given to them?
  12. JEFFREH Administrator

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    Good question, I've never thought too deeply about that =)

    I would say you probably hit the nail on the head there. A gas or liquid form that could be taken in through the insect's spiracles would probably be the most efficient way to provide the hormone to a large quantity of worms. Possibly even a food source for them that could be ingested? That would allow the supplier to simply do a quick spray over the population before sending them out, or just raising them on the stuff. You've inspired me to send out some emails! I'll be looking into this...

    I do know that the specific hormone is one that is most likely used as a type of insecticide. Crops are sometimes sprayed with insecticidal hormones if the pest is the adult form of the insect, so keeping it in a juvenile state would prevent as much destruction. I think I've read before that it is also how they manage some mosquito infested areas, because keeping them in the juvenile state prevents the adult mosquitoes from biting, passing disease, and reproducing.
  13. LittleMick Embryo

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    JEFFREH, can you post the orignal source for the nutritional values for all these feeders please.
  14. JEFFREH Administrator

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    Sure thing =)

    I'll give you several links because there are some varying bits of values, but thats probably based on the individual insect being used and what it was fed. Here is the table directly from our website here at reptilerooms, under the caresheet section:

    Insect Nutritional Values ()
    Published: June 18, 2008

    Insect Nutritional Values
    Crickets Fruit Flies
    Moisture 75% Moisture 59%
    Ash 1% Ash 2%
    Protein 17% Protein 20%
    Fat 6% Fat 14%
    Other 1% Other 5%

    Mealworms Wax Worms
    Moisture 61% Moisture 62%
    Ash 1% Ash 1%
    Protein 20% Protein 16%
    Fat 14% Fat 20%
    Other 4% Other 1%

    Zophobas (Superworms) Redworm
    Moisture 58% Moisture 84%
    Ash 1% Ash 2%
    Protein 19% Protein 11%
    Fat 17% Fat 2%
    Other 5% Other 2%

    Nightcrawler Silkworm
    Moisture 85% Moisture 75%
    Ash 1% Ash 7%
    Protein 10% Protein 10%
    Fat 2% Fat 6%
    Other 2% Other 2%

    Here the actual link since it might be hard to line up the values easily

    I'll just post the other links and you can view them straight from the sources and compare <---he got the info from Feeders Inc. <---Scroll down just a bit, theres a small chart on the right <--- look around for bugs, also has salad items <---- an interesting chart about halfway down discussing weights of feeders

    There are several more out there, you could probably come up with a few more from searches but these are what came to mind off of the top of my head =)

    **Edit notes: I've consistently found with other sources that silkworms have SIGNIFICANTLY higher amounts of protein than suggested in the RR table (like upwards to 60-70% protein). The values listed in that particular chart there actually better represent values of a Hornworm. This is why it's important to compare from multiple sources.

    Also: Silkworms contain an enzyme called Serrapeptase. It's uses have been known for many years in countries where silkworms are eaten as a regular food source, but here is a quote from the Beautiful Dragons website about it:
    "Contain an enzyme called serrapeptase, this has properties that make calcium absorption more efficient, can reduce inflammation, pain and best of all it can break down arterial plaque."

    Also, note that with Superworms and Mealworms that the chitin in the shell actually blocks some fat absorption. This is why the protein/fat ratio in supers is typically acceptable due to less fat being actually absorbed (and a little less shell to greater size to allow for more gutloading).
  15. JEFFREH Administrator

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    "Do you recommend/sell "Giant" Mealworms?

    The so-called "Giant" Mealworms are created by spraying "common" Mealworms with an insect growth hormone to keep them growing instead of pupating as they would normally. Because of this, we feel that the "Giants" are a poor food choice for your Reptiles. However, we do highly recommend them as fishing bait!"

    Thats from's FAQ section, I kind of feel bad because I sent a couple of emails out already to a few places before stumbling across this. It looks like the worms are indeed sprayed with the growth hormone and the supplier here clearly advises against feeding them.

    Also, I've found that many feeder suppliers have nutritional info straight on their website, in addition to the others I've linked, also has some posted. And again, comparing and contrasting all of those sites is probably the best way to get a mean average of what is said about fat and protein percentages, and overall nutritional value.
  16. teach920 Embryo

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    Thank you for clarifying/researching all of this's very good information to know...I feel very fortunate that for me, when I was in a situation where crickets were scarce or hard to come by for a time, I choose superworms as a substitute, instead of the giant mealworms.....until now I would never have known the dangers of feeding the "giant mealworms" I have seen offered in the least now I know to avoid them completely.
    Again, thank you for informing us.
  17. LittleMick Embryo

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    N1 JEFFREH, that's great matey, I'll print out them nutritional values and check out the links over the weekend when I have more time. I'm reading too many forums during the week, lol.

    As it happens I am reading a book about keeping Bearded Dragons, and I came across this

    Bearded Dragons are usually fed commercially -bred invertibrates such as crickets (Acheta domestica), mealworms (Tenebrio molitor), giant mealworms (Tenebrio molitor), superworms (Zophobus morio), wax worms (Galleria mellonella) and juvenile Madagascar hissing cockroaches (Gromphodorhina portentos). These are available for sale in many pet shopsand by mail order.
    So after reading this post I was surprised to see this info in abook for Beardies.
  18. Shanna66 Well-Known Member

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    alot of care books for any animal will have bad info. its up to the reader to research every fact they are told. ive got a leopard gecko book that says that calci sand is the best substrate for a leo. you dont need to be right to get a book published sadly
  19. Domino Embryo

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    For the record, I have chucked the giant mealworms. Bought Domino some butterworms, and he is eating those right now :D

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