Praying Mantis Feeding: Live Prey a Third of Its Length, Every Other Day, and Nothing Left in the Cage
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A praying mantis is a predator that will only eat what it catches, and feeding one is a matter of offering the right size of live insect at the right interval and taking away whatever it does not kill. Here is the prey by life stage, the two rules that matter, and the one reason a mantis stops eating that is not a problem.
Feeding Schedule
| Stage | Prey | How often |
|---|---|---|
| Newly hatched nymph | Flightless fruit flies, aphids, springtails | Daily to every other day |
| Growing nymph | Bottle flies, small crickets, roach nymphs, small moths | Every other day |
| Adult | Bottle flies, roaches, moths, grasshoppers, waxworms, black soldier flies | Every other day, more for a female, less for a male |
Every other day, as much as the mantis will take, is the working rhythm, and the range around it is wide: every one to four days depending on the species, the prey, the size of the mantis, whether it is well fed or thin, and its life stage, since an adult female needs more food than an adult male. A mantis stops eating when it is full, which is what makes the rhythm forgiving. It does not stop being offered food, which is what makes overfeeding possible, and an overfed mantis lives a shorter life.
Prey no longer than a third of the mantis. Some species will tackle an insect as large as themselves, and the danger is not the meal but the fight: a grasshopper, cricket or roach that is not eaten will chew the legs and wings of the mantis it was meant for. Small prey, watched, and whatever is left comes out.
What Praying Mantises Eat
Live insects, and only live ones. A mantis is an ambush hunter that keys on movement, and most will ignore a dead insect entirely. The prey grows with the mantis: fruit flies and aphids for the smallest nymphs, then bottle flies, small crickets and roach nymphs, then for an adult almost any insect it can handle, flies, roaches, moths, grasshoppers, waxworms and black soldier flies among them.
Offer it so you can see it taken. Live food released into an enclosure can hide or escape, and a mantis whose prey keeps vanishing starves beside a cage full of insects. Fine forceps let you present a fly to the mantis and watch it strike, and a small enclosure keeps the prey where the mantis can find it.
Gut-load and hydrate the feeders. A feeder generously hydrated and gut-loaded for at least 24 hours is the mantis's nutrition, and a dry cricket from the shop is a poor meal. The gut-loading guide covers the feeder diet, and the feeder colony itself needs space, warmth and food to be worth eating.
Crickets, with care. Crickets are a common feeder and a risky one: a cricket that is not eaten within the hour chews on a resting mantis, and a soft, freshly molted one most of all. One specialist sheet skips them entirely in favor of flies and roaches. If crickets are the feeder, they go in one at a time and the survivor comes out.
Water is a droplet. A mantis drinks water it runs into, so a light misting of the enclosure once a day gives it water and raises the humidity in one go. Mist fine rather than heavy, since a small mantis can be trapped and drown in a large droplet, and never leave a dish.
Culturing Fruit Flies at Home
A nymph eats fruit flies for weeks, and a culture raised at home keeps them coming for the price of media and a cup. The two flightless species split the job: Drosophila melanogaster is the smaller fly for the youngest nymphs, and D. hydei is the larger one for the instars after.
- Put about 1/4 cup of hot water in an empty 32-ounce deli cup, add 1/3 cup of fly media, and pour another 1/4 cup of hot water evenly over the top.
- Sprinkle 10 to 15 grains of baker's yeast on the surface and add a wad of excelsior for the flies to climb.
- Once it cools, tip in 40 to 100 flies from a producing culture and cap it at once.
- Keep it at 70 to 75°F and 50 to 60% humidity, in normal room light, since a dark cupboard encourages mold.
A melanogaster culture shows larvae in 4 to 6 days and starts producing flies around day 11 to 13, and it keeps producing to about day 30 to 35. Hydei is slower, producing from around day 19 to 22. Starting new cups on a regular schedule keeps cultures of staggered age, so a fresh one is producing as the oldest fades. Mites are the usual way a culture fails: start from mite-free flies and keep the shelf clean and away from plants and damp enclosures.
Larger feeders, crickets and roaches, can be kept or bred the same way any insect colony is, and they need space, the right warmth and their own food and water to be worth feeding.
Foods to Avoid
Anything longer than a third of the mantis. Bees and wasps, which sting. Wild-caught insects from anywhere sprayed, which the invertebrate pesticide hazards guide treats as the biggest single risk to a pet insect. Dead insects, which are ignored and rot. Mealworms and superworms as a staple, which are hard-shelled and fatty. And any live prey left in the enclosure after the feeding.
Why Praying Mantises Stop Eating
A molt is coming. The commonest reason and a normal one. A mantis refuses food for a few days before it sheds, hangs still from the roof, and eats again once its new legs and mouthparts have hardened, several hours to a day after. Pull the live prey out the moment feeding stops. The invertebrate molting guide covers the height and humidity that let the shed succeed.
It is full. A mantis with a rounded abdomen that turns down a fly is full, and offering again tomorrow is the answer.
It is cold. A mantis below its species' range slows down and stops hunting. Warm the room.
It is an adult male. Adult males eat less than females, and an old male eats very little in its last weeks.
It cannot see the prey. Fruit flies that have wandered to the ceiling, or a cricket hidden in the substrate, are not food to a mantis that hunts by sight. Present it.
When to Worry
A mantis off food for a few days with a full abdomen is molting or resting. One that refuses for a week after a completed molt, that cannot hold the mesh, that has a shrunken, wrinkled abdomen, or that has a bent limb from a bad shed is the animal in trouble, and the praying mantis health guide sorts those signs. There is no vet for a mantis; the fixes are food, warmth and humidity, and for a mantis at the end of its year, the honest answer is that it is at the end of its year.
A live fly a third of its length every other day, watched, with the leftovers out and a mist in the evening. A mantis fed that way eats itself through its molts to adulthood, and the only way to shorten that is to feed it more.
Sources & Further Reading
Frequently Asked Questions
How often should I feed a praying mantis?
Every other day, as much as it will take in one sitting, since a mantis stops when it is full. The range across species, sizes and condition runs from every day to every four days, and an adult female eats more than an adult male. A mantis that looks thin eats sooner; one with a swollen abdomen waits.
What size prey can a mantis take?
Nothing longer than about a third of the mantis's own length. Some species will tackle prey as large as themselves, and it is the fight that costs them: a big cricket or grasshopper that is not eaten chews on the mantis instead. Fruit flies for the smallest nymphs, then bottle flies, small crickets and roach nymphs, then larger flies, roaches, moths and waxworms for an adult.
Will a mantis eat dead insects?
Almost never. A mantis is a visual ambush hunter that responds to movement, and a dead insect on the floor is ignored. Live prey, offered on fine forceps so you can see it taken, or released and watched, is the whole method.
My mantis has stopped eating. Is it dying?
It is probably about to molt. Refusing food for a few days before a shed is normal, and the response is to pull any live prey out and wait. A mantis that refuses for a week after a molt, cannot hold the mesh, or has a shrunken abdomen is the one to worry about.
More on the Praying Mantis
Praying Mantis care guide
🦗 How Much Does a Praying Mantis Cost?
🦗 Can You Hold a Praying Mantis? Gently, and Rarely
🦗 Common Praying Mantis Health Issues (Molting Is Where Nearly Everything Goes Wrong)
🦗 Praying Mantis Enclosure Setup: Height, Humidity, and a Mesh Lid
🕷️ 10 Surprising Praying Mantis Facts
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Written by Michael Ryan
Mike keeps two rescued bearded dragons, Dex and Cera, and writes the care guides on BeastlyFacts from his own research and mistakes. He is not a veterinarian.
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