40 Fun Facts About Mealworms

Which packaging plastic did lab mealworms live on in a 2015 study that stunned waste researchers?

Styrofoam was thought to be non-biodegradable until that study, in which mealworms fed nothing else stayed as healthy as those on a normal diet.

Mealworms were among the first Earth creatures to circle the Moon, aboard a 1968 probe from which country?

The USSR flew them on Zond 5, which swung round the Moon and splashed down in the Indian Ocean with its living cargo safe.

Which North American birds do nest-box fans famously tempt into their gardens with dishes of live mealworms?

Bluebirds take mealworms so readily that fans use them to lure pairs to a nest box and to feed chicks when bad weather hides wild insects.

What is the name of the motionless, non-feeding stage a mealworm enters before emerging as an adult beetle?

Pupa is the stage in which the mealworm's body is rebuilt into a beetle's; it starts out pale and darkens just before the adult breaks free.

Which of these insects shares the mealworm's four-stage life cycle, with a motionless resting stage before adulthood?

Butterfly and mealworm both pass from egg to larva to a resting stage and then adult, which is why the young look nothing like their parents.

Which Alpine country approved mealworms as food for people in May 2017, opening the door to insect burgers?

Switzerland cleared mealworms for the dinner table in May 2017, though most insect foods on sale are still snacks and bars, not meat replacements.

Mealworms were the main meat for volunteers sealed inside Lunar Palace 1, a mock Moon base in which country?

China built Lunar Palace 1 in Beijing, where a crew of three spent 105 days in 2014 raising their own crops and mealworms to eat.

Where do keepers store live mealworms for weeks to slow their growth and delay the change into beetles?

In a refrigerator, a mealworm's metabolism slows so far that a tub can be held for a few weeks, or even several months, before use.

Which dry food do keepers typically fill a mealworm tub with, so it serves as both bedding and dinner?

Wheat bran is both bed and dinner for mealworms, which burrow through it and need only a piece of fruit or vegetable on top for moisture.

Despite the name, a mealworm is no worm; which feature, shared with adult beetles, gives it away?

Six jointed legs mark a mealworm as an insect larva, the young of a darkling beetle, whereas a true worm has no limbs at all.

Which tough material forms a mealworm's outer skeleton, just as it does a crab's shell?

Chitin builds the armour of insects and crustaceans alike, and its toughness is why some reptiles digest hard-skinned mealworms poorly.

In 2021 dried mealworms became the first insect food authorised for sale across which group of countries?

The European Union authorised dried mealworms in June 2021 after its food-safety agency judged them safe, its first such verdict on any insect.

People with an allergy to which food are warned that eating mealworms could trigger a reaction too?

Shrimp and mealworms carry similar muscle molecules, so antibodies primed against one can react to the other, as they also can with dust mites.

Which mineral are shop-bought mealworms so short of that reptile keepers boost it before feeding time?

Calcium is so scarce in shop-bought mealworms that pets raised on them risk deficiency disorders, so keepers fatten the larvae on a mineral-rich diet first.

Which reptiles rode alongside mealworms on the first animal flight around the Moon in 1968?

Tortoises, two of them, came home alive from the week-long trip, having lost about a tenth of their body weight on the way.

With no water dish in the tub, mealworms usually get their moisture from a slice of which vegetable?

Potato slices give mealworms all the water they need, and an open dish is skipped because too much damp turns the bedding mouldy and kills them.

What inside a mealworm does the real work of breaking down plastic, according to the 2015 studies?

Its gut bacteria do the digesting: dose a mealworm with antibiotics and it can no longer break plastic down.

Mealworm beetles can carry the young of a tapeworm whose usual final host is which animal?

Rats pass the tapeworm's eggs in their droppings, mealworms swallow them while feeding, and the cycle closes when a rodent eats an infected beetle.

In which African desert do darkling beetles, the mealworm's family, drink by catching fog on their backs?

Namib fog is these beetles' water supply: droplets gather on their wing cases and run down their backs to the mouth.

The lesser mealworm, also called the litter beetle, is a notorious pest in sheds full of which farm animals?

Chickens can catch dozens of diseases from lesser mealworms, which live in the floor litter and are eaten by pecking chicks.

Which naturalist gave the mealworm beetle its Latin name, Tenebrio molitor, in the 1758 edition of Systema Naturae?

Carl Linnaeus chose the genus name Tenebrio, Latin for one who shuns the light, a fair label for insects that hide in dark corners.

The 'molitor' in the mealworm's scientific name, Tenebrio molitor, is Latin for which grain-handling trade?

Miller is the meaning of molitor, a nod to the mills and grain stores where the larvae have long turned up as pests.

Which name do pet shops give Zophobas larvae, the mealworm's giant cousins from tropical Central and South America?

Superworms reach 50 to 60 millimetres, about twice a mealworm's length, and the adults can release a pungent defensive chemical when provoked.

Under which trade name are lesser mealworms, a smaller relative also farmed as food, usually marketed?

Buffalo worms are barely a centimetre long when fully grown, less than half the size of an ordinary mealworm.

What do commercial growers add to the feed of 'giant' mealworms to make them outgrow ordinary ones?

Juvenile hormone holds a mealworm in its larval stage, so instead of changing it keeps eating and swells to an abnormal size.

What do entomologists call each growth stage of a mealworm larva between one moult and the next?

Instar is the term, and a mealworm must shed its skin to enter each new one because its hard outer casing cannot stretch as it grows.

What are the hardened front wings called that cover an adult mealworm beetle's back like a shield?

Elytra are covers, not flight wings: a beetle lifts them to unfold the flying pair beneath, though mealworm beetles rarely bother to take off.

Mealworms belong to which insect order, the largest of all, whose name means 'sheath wings' in Greek?

Coleoptera, the beetles, number about 400,000 described species, roughly a quarter of all known animal species.

What is the term for insect droppings, which build up in a mealworm tub and are sold as fertiliser?

Frass from insect farms is sold as a plant fertiliser, and at home a whiff of ammonia from the tub means it is time to sift it out.

What do male mealworm beetles release to attract a mate, a signal that grows weaker in inbred males?

A pheromone from the male does the wooing, and females can smell the difference: they prefer the scent of outbred, well-fed males.

What do mealworm beetles rely on, as some polar fish do, to survive freezing weather?

Natural antifreeze molecules in the beetle's blood latch onto tiny ice crystals and stop them growing before they can do fatal damage.

Wireworms, the hard-bodied larvae that look much like mealworms, are the young of which insects?

Click beetles can snap a spine on the chest hard enough to bounce themselves into the air, and some of their wireworm young are serious crop pests.

Which chirping insect is sold beside mealworms as a standard pet-shop feeder and ground into edible powder?

House cricket farming took off after 1950, when the species became the standard feeder insect, and its powder now goes into burgers and pasta.

What is the scientific term for eating insects such as mealworms, a custom of around 3,000 ethnic groups?

Entomophagy is everyday eating across much of Asia, Africa and Latin America, with about 1,900 edible insect species on record.

Mealworms have no lungs; through which openings along the sides of the body do they take in air?

Spiracles lead into a network of fine tubes that carry air straight to the tissues, and an insect can shut them to save water.

Engineers at which California university co-wrote the 2015 studies showing that mealworms can digest plastic?

Stanford engineer Wei-Min Wu worked on the papers with a team at Beihang University, the first detailed evidence of plastic being broken down inside an animal.

Dried mealworms are prized as feed for fish and garden birds chiefly for a high content of which nutrient?

Protein is the selling point: mealworm meal is being tested as a stand-in for fish meal and soybean meal in livestock feed.

Which colour names the common mealworm species, setting it apart from its close relative the dark mealworm?

Yellow mealworm is the full name of Tenebrio molitor, whose larvae are paler than those of the dark mealworm, a species sold as mini mealworms.

Besides feeding pets and wild birds, live mealworms are widely sold to hobbyists for which outdoor use?

Fishing bait is a classic use, which is why tubs of live mealworms sit in tackle shops as well as pet stores.

Adult mealworm beetles end up dark brown, but what colour are they when they first emerge?

Whitish at first, the newly emerged adult soon darkens to brown, and although it has wings it spends its time crawling, not flying.