Raising mealworms: feeding suggestions
What kind of things can you give mealworms anyways? Is there anything that is bad for them or stunts the growth process? This is a good list of different things that are okay to feed your mealworms, beetles and such.
- Add a chunk of cabbage, raw potato (half a potato, or a chunk about 1″x3″), a slice of bread (which the mealworms will also eat), romaine lettuce, kale (high in calcium and inexpensive), yam (also nutritious) or apple slices (1/4 of an apple is enough for 1,000 mealworms, once or twice a week - I find apples get moldy too quickly). Some people use celery (e.g., bottom end of bunch), broccoli stems, carrots (grated carrots on a plastic lid), banana peels, or asparagus chunks. Cabbage leaves do not get as moldy as some other choices. A crust of bread (replaced when dry) can also be laid face down on the bedding.
- You may wish to wash/peel vegetables first to prevent the introduction of pesticides.
- Place potato/apple slices cut side up, even with top of bedding. By putting the skin side down, you keep the bedding/dry food from getting too moist.
- Try kiwi skin with about 15% of fruit still in it (after scooping out the rest with a spoon for your own enjoyment). A.M. Prendergast found that it made mealworms grow about 3 times fatter and 30% longer in just 2-3 weeks versus wheat bran alone. The worms also use the skin as a “cave” as it dried and curls up.
- Cover cabbage etc., with a cloth to keep it from drying out if you use a heat lamp.
- To make them easier to replace (every 2-3 days or weekly), put vegetable on a little plastic lid, tinfoil pie plate or a piece of cardboard, or stick a toothpick in it. Replace immediately if mold appears.
- More is not better. If you put too much in, or leave it too long, it will get moldy or become a gooey mess.
- If you use burlap or newspaper, you can spritz it lightly with water on a daily basis. Do not soak, and do not wet bedding. You can also put in a moist (not wringing wet) paper towel, changing it daily. You can put down a piece of aluminum foil under the dampened burlap/paper to prevent grain from getting wet.
- “Cricket quencher,” a gel polymer that insects suck water out of, can also be used. It will not wet bedding material.
- Small amounts of moist cat food (like Tender Vittles) can also be used, and will provide extra protein.
- Placing adult beetles on moist blotting paper overnight may increase egg production.
- Place a small but tall (so they do not drown) bowl filled with water in the middle of the farm to increase relative humidity. A sponge can be placed in the bowl to increase the moist surface area. Fawzi Emad uses a moist sponge wired to the container lid. You can also put the bottom of the sponge in a plastic baggie (to prevent the meal from getting wet and moldy) and stand it upright in the corn or oatmeal. Re-wet the sponge weekly, and wash it when needed.
Food/Substrate/Bedding: The more nutritious the food, the more nutritious the mealworms will be. Layer it in 2-3″ inches deep. Replenish the food often, as the worms eat a lot. Change the food out about once a month. Feed the beetles too (same stuff). I mix up a big batch with supplements and store it in a plastic bin with a screw top lid so I don’t have to worry about flour moths and other critters getting into it.
Fine particles (fine wheat bran, corn meal, chick starter) make it easier to sift out large mealworms. Larger particles (e.g., rolled oats) with grown worms make it easier to sift out frass so you do not waste food. You can buy some of these items from an animal feed store or bulk food store. Commonly used food sources are listed below. They will also eat corn cobs (hiding inside):
- wheat bran, red and/or white (about $7.00/20 lb. bag at a feed store) or chaff. Coarse or fine. Put it in 1.5-2″ deep. Preferred by some breeders.
- rolled oats (oatmeal - uncooked, old fashioned - not instant.
- oat bran
- corn meal (not corn STARCH)
- chick (poultry - chicken or pheasant & turkey) starter/mash - very nutritious. Available from a feed store. Get NON-MEDICATED. You can put it in four layers each of 1/4″ of mash covered by burlap. Easy to sift. 55 lb. bag costs about $11.
- ground dry dog or cat food encourages pupation. It can also be given to worms prior to offering them to pets to increase protein content.
- leftover low sugar cereal
- birdseed (e.g., milo)
- wheat flour (whole wheat for added nutrition)
- grain mixture:
A few scraps of cloth or wrinkled paper layered with the bedding will prevent the meal from packing too solidly.
Supplements: You can add the following to the dry food/bedding: wheat germ, finely ground egg shells or cuttlebone (for calcium), soybean meal, Wombaroo insectivore mix, fish flakes, fine mouse cubes, bone meal, graham (whole wheat) flour, and dry brewer’s yeast (provides proteins and trace elements essential to the insects’ growth and makes larvae grow more. Brewer’s yeast can be obtained at health food stores. It’s pricey, so you might want to buy it in bulk at a feed store or online. You can sprinkle the vegetables/fruit with calcium and vitamin supplements to add nutritional value. Experiments where skim milk (calcium source) was added to wheat bran (1:3 or 1:2 ratio) yielded better growth than wheat bran alone.
Cloth or newspaper covering: You can partially cover the food surface (about 2/3) with several layers of newspaper, brown grocery store bags, paper towels, or a folded piece of cloth. Leave space between the paper and edges of the container.
Worms will crawl between the newspaper layers to pupate, which makes it easy to collect them.
The beetles will lay eggs on cloth. However, it is difficult to get the beetles off the cloth when maintaining the farm. Beetles will also lay eggs directly on the food source. Or you could put a thick, clean, dry hunk of bark on top of the bedding. The beetles will lay eggs on it.