Mealworm's Diet

I'm doing a research project relating to mealworms. My question is : Do mealworms eat flour? Can I raise them in a bed of flour, the kind use for baking ?

Mealworms are the larvae of Darkling Beetles (Tenebrio molitor). They are very sensitive to vitamin deficiencies, so it is advisable to raise them on a varied diet. I raise them for my frogs and toads and have had a colony continuously growing since 1968. I use a wide variety of grains and cereals, including corn meal, rice, corn flakes, oatmeal, leftover flour, and farina. For a moisture source, I put in apple peels, potato peels, and the outer leave of head lettuce, as well as other peels from a variety of other vegetables. The more varied the diet, the healthier will be the mealworms. Trying to raise them on flour alone will likely result in a short-lived colony.

Don

Don, now I know why over the years I have never been sucessfull in keeping mealworms alive unless stored in the frig. Sounds like a project. I guessing you let some of the worms mature into beatles which then mate and lay eggs to produce more larvae?

Fm3

Mealworms may eat flour but it's not ideal. As Don says, they need variety. Mine get Gerber baby oatmeal cereal, three kinds of cricket foods (mix of grains and vitamins), carrots, apples, grapes, kale, and so on.

The beetles I've had like to lay eggs in cork bark but will also lay on wet paper towels or in the cereal. I've never had a great survival rate for newborns.

My page on mealworms is at http://www.fishpondinfo.com/worm.htm

FM3
Yes, there are always adults that lay eggs, etc. and the cycle continues indefinitely. They seem to like potato peels as the peels dry out and gives them a place to burrow and lay eggs, etc. I really don't do anything special other than dump in vegetable trimmings and add new grains once in a while. About every year or two, I use a piece of window screen to separate the dried up vegetables and dried up dead beetle carcasses and kind of clean up the colony. I've always used an earthen pickle crock as the container. It's deep enough to keep beetles from crawling out. I don't know why they don't just fly out. They never have.

Don

Do you feed these to your out door frogs and toads, placed in a dish that they can't crawl out of?

FM3
I feed them to frogs and toads that are kept in terraria in the house. I have always had some kind of amphibian or reptile in a captive state. Originally, I started the colony while I was in college and had been given a California Newt. The critter lived for 16 years! Over the years, while I was teaching, I also had students bring in frogs, toads, salamanders, turtles, etc. that the colony helped feed. My box turtle, water turtle hatchlings and tomato frog are the current critters that get them. My granddaughter is always bringing me some critter that she wants me to keep for her. Check out the video, "Who Gets the Worm" that I made last winter of the toad she gave me. http://youtube.com/dperry428
Some years ago my classroom was the recipient of a gift hedgehog that also ate mealworms like they were going out of style.

Don

Don, the mealworm beetles can't fly. I did a quick search on-line and read that a few people claim they have seen one fly but most sites say they cannot fly. I've never seen any of mine fly. They do have wings but never open them.

I can't believe you only clean their container every one or two years! I clean mine out weekly. If there's a lot of insects, it sometimes takes a while to hand pick them out but, most weeks, I just dump them in to a collander, clean the cage, and return them. Green and white fungus grow in my insect tanks. so weekly cleaning is needed.

Robyn
I didn't know they don't fly. Seems odd.

If you're getting fungus in you colony, it must be too moist. I'm surprised how little moisture that my colony needs. There have been times when I've neglected it for months and not added any veggies or other moisture and it just chugs along. I really don't clean out the colony much at all, but when I do, I remove tons of dried up beetle carcasses, and many of those are really broken into tiny pieces. I wonder if the crock that I use has something to do with not having any fungus problems. It is rather old and porous, so I'm wondering if it doesn't wick away excess moisture that would be required for mold growth. I remember some years ago that I tried to start a second colony for another person and after just a few weeks, had black mold growing in a layer at the bottom of the container under the medium. That container was non-porous plastic and would have retained moisture. All I know is that the crock has supported the colony for forty years. The only other thing I do every few years is dump a store-bought container of mealworms into the colony to enhance the gene pool of the colony. After numerous generations on inbreeding in the isolated population, the larvae begin to get sickly-looking....almost whitish in coloration. After introducing the new "blood", the colony gradually (over months) gets "normal" again.

Don

Don

My containers are plastic. I put in wet (squeezed out) paper towels for moisture which the mealworms love (they crawl all up in them). The fungus loves that too though.

Your colony is 40 years old! It's never had a die off or been completely empty in that long? You don't do anything to help raise the babies? You don't separate the larvae from adults from pupae? I do that, or they eat each other. Your magic crock pot must be huge!

Don it sounds like you need to teach some not so young eager students how to raise meal worms. Another video production? I'm going to show my ignorance but what is a "earthen pickle crock" made of clay?

Robyn

Yes, I started the colony in 1968 when my wife's aunt gave me a California Newt that she didn't want anymore. It lived with me for 16 years. I have kept the colony going ever since. From time to time, through lack of need, I neglected the colony and it would be minimally populated with larvae/adults. All I needed to do to pick up the population was to add some new food and potato peels and within a couple months, had a flourishing colony again. When there got to be too much debris to easily extract larvae, I'd clean it. No, I don't attempt to separate adults and larvae. There are all stages, tiny larvae, large larvae, pupae and adults, together. Eggs are too small for me to see. In fact, it was perfect for showing stages of insect development in science class. I pretty much just leave it alone unless I need to get some larvae for a critter. Right now, I have a second, smaller crock close to the Tomato Frog enclosure. The larger one is in the basement. By the way, they seem to do much better when they're kept in the dark. I've attached some pictures for Froggy to see what I mean by a pickle crock and for you to see that the colony is in need of maintenance.

Froggy
The best way to tell you what a pickle crock is, is show you. The pix below are of a 2 gallon and a 10 gallon crock. I call them pickle crocks because that is what my mother used to make pickles. My mother's side of the family were Amish, my grandmother being the first generation to live outside the community, so we still did much of our own food production when I was a kid. We were not affluent, with 5 children in the family and had moved to Illlinois when my father was laid off from his job with the railroad in Pennsylvania a couple years after WWII. Short story....we needed to most things for ourselves....canning, pickling, making many of our own clothes, etc. I think the real name of the containers is "pickling jars", but they are fired clay.

This is a picture of a 10 gallon crock:




This is the inside of it:




This is a 2 gallon crock that I put next to the Tomato Frog enclosure:




And this is a picture of the Tomato Frog, because I know someone will want to see it, so I'll just put it here:




Wow, I didn't think mealworm diet would create such a long string!!

Don

Correction! That picture of the crock in the basement is my 4 gallon crock. I broke my 10 gallon.

Don

It has been every informitive Don. I can't believe how simple you have made it. I have raised a host of various frogs, lizards, toads over the years and always had trouble at times finding the right sized mealworms for the various pets my kids just "had to have". Plus I do fish, not as mush as I used to, but the larger mealworms make excellent bait for panfish. Thanks so much the pics it really helped. I was suprised at how little material was inside the crock.
I alwasy seem to have a container of forgotten wax worms, mealworms or night crawlers in the frig.

Tom

I see one beetle in the crock. So, what are we looking at? I'm guessing the old, degraded peels from potatoes, apples, etc.? But, what are those larger things that look like pieces of cloth? Under the top debris, how deep is the material? You said there was a large colony under there. How many mealworms would you say you remove each week to feed the animals? I give my chickens almost 100 a week so that would require a huge colony if I didn't just buy the mealworms. Last week was the first time in months they had any for sale after the country-wide die-off that suppliers had. It would have been nice to have a colony that could sustain itself.

Mealworms are plenty interesting!