50 Fun Facts About Beetles

Which insect defends itself by firing a near-boiling chemical spray from its rear with an audible pop?

The bombardier beetle mixes hydroquinone and hydrogen peroxide in a chamber in its abdomen, and the reaction heats the spray to near the boiling point of water. It can fire roughly 20 times before running dry.

African dung beetles roll their balls in a straight line at night by steering with which sky feature?

The Milky Way is their compass: dung beetles are the only insects known to orient by its glow. A straight path gets the ball away from the dung pile before another beetle can steal it.

The 'lady' in the name ladybird honours which religious figure, often shown in a red cloak in early art?

The Virgin Mary was known as Our Lady, and in Britain the insects were first called Our Lady's birds. The seven spots of the common European species were said to stand for her seven joys and seven sorrows.

Males of which insect group wrestle rivals with hugely enlarged jaws?

Stag beetles are named for the males' oversized mandibles, which resemble a stag's antlers and are used to wrestle rivals off favoured mating sites. The European species is the largest beetle on the continent.

In which country are horned rhinoceros beetles kept as popular pets?

Japan is so fond of pet beetles that vending machines dispensing live ones were developed there in 1999. Rhinoceros beetles were once gathered from the wild but are now also bred in captivity.

Counting the male's long horn, which tropical American insect is the longest of all beetles at up to 17 cm?

The Hercules beetle can reach 173 mm with its horn included. Fighting males grab a rival between that horn and a smaller one on the head, then lift and throw him.

Which naturalist, as a Cambridge student, popped a beetle into his mouth to free a hand for another?

Charles Darwin was already holding a beetle in each hand when he spotted a third around 1828. The one in his mouth squirted acrid fluid, so he spat it out and the third escaped too.

Which predatory insects chase prey in bursts, sprinting at up to 9 km/h and then stopping to look again?

Tiger beetles may simply outrun their own eyesight, moving too fast for their visual system to process images. The quickest species covers about 125 of its own body lengths every second.

Which wood-boring insect of old oak buildings attracts a mate by knocking its head against the timber?

The deathwatch beetle's tapping carried through silent houses during bedside vigils for the dying, so it was long feared as an omen of death. It prefers oak that has been dead for about sixty years.

Which darkling beetle larvae, long sold as pet food, were approved as human food in the European Union in 2021?

Mealworms are not worms at all but the young of the yellow mealworm beetle, Tenebrio molitor. They are rich enough in nutrients to go into livestock rations, and can even break down polystyrene.

What are the hardened front wings called that cover a beetle's delicate hindwings like a pair of cases?

Elytra swing open so that the folded wings beneath can extend for take-off. Many scarabs and jewel beetles can even stay airborne with them closed.

In a beetle's complete metamorphosis, like a butterfly's, which life stage comes between larva and adult?

Pupa is the resting stage in which a grub's body is rebuilt into an adult beetle. Some larvae build a cocoon around themselves first, at the end of their final moult.

Beetles are the largest order of insects; roughly how many species have scientists described so far?

About 400,000 described species means roughly one in four known animal species is a beetle. New ones are found so often that estimates of the true total run from 0.9 to 2.1 million.

Which scarab-headed Egyptian god was thought to roll the sun across the sky as a beetle rolls a dung ball?

Khepri was the god of the rising sun, and his name means he who has come into being. The beetle seemed to create itself out of nothing, just as the god was said to have done.

Enterprise, Alabama, raised a monument to the boll weevil, a beetle that had ravaged which local crop?

Cotton had dominated the town's economy until the weevil arrived and forced farmers to diversify. The 1919 monument thanks the pest for pushing Enterprise towards mixed farming and manufacturing.

Which ten-striped crop pest did East Germany call the Amikäfer, claiming American planes had dropped it?

The Colorado beetle, a potato pest native to the Rocky Mountains, was spreading across Europe at the time. Several Warsaw Pact states blamed the CIA for the infestations.

The toxin cantharidin, once used as an aphrodisiac, comes from which metallic green beetle with a misleading name?

Spanish fly is a blister beetle found mainly in southern Europe, and its reputed effect was really irritation of the urinary tract. In 1954 a man was jailed after sweets he had laced with it killed two women.

Photinus carolinus fireflies draw crowds by flashing in unison each June at Elkmont, in which US national park?

Great Smoky Mountains crowds are so large that driving and parking are strictly regulated during the two-week mating season. Photinus carolinus was the first North American firefly found to flash in sync.

Fireflies produce their cold light when an enzyme oxidises which compound in their light organs?

Luciferin gives off a cold light with no infrared or ultraviolet in it. The enzyme that triggers the reaction, luciferase, is now used in forensics and medicine to detect the energy molecule ATP.

Which insects of the family Elateridae can snap a spine into a notch on the chest, bouncing themselves into the air?

Click beetles make a sharp snapping sound as they launch, which is how they got their name. Their tough, soil-dwelling larvae are the wireworms that damage potato, maize and wheat crops.

Which insects of the family Gyrinidae have each eye divided into one part above the waterline and one below?

Whirligig beetles are named for a different habit: swimming in rapid circles when alarmed. Their split eyes recall those of the four-eyed fish, which also live at the surface.

Which African scarabs have grubs that can weigh 100 grams, putting them among the largest insects on Earth?

Goliath beetles weigh about twice as much as grubs as they do as adults. In captivity the larvae need so much protein that keepers raise them on dry cat and dog food.

Natural history museums keep colonies of dermestid beetles to carry out which delicate job?

Cleaning skeletons is a job the larvae do by eating the soft tissue off the bones. Forensic scientists also study them on corpses to help estimate the time since death.

Male jewel beetles won researchers an Ig Nobel Prize after being found trying to mate with which discarded objects?

Beer bottles of a stubby brown kind have glass bumps that catch the light like the surface of a giant female. Males gather on them and try to mate.

Head-stander beetles of the Namib Desert climb dunes at night and tilt their bodies to drink water collected from what?

Fog condenses on the beetle's upturned back and the droplets run down into its mouth. The trick, called fog-basking, is known in only two species.

Which British geneticist reputedly told theologians that the Creator must have an unusual fondness for beetles?

J. B. S. Haldane was pointing at sheer numbers: beetles make up almost 40% of all described arthropods. He had been asked what the natural world revealed about the mind of its maker.

Aristotle named beetles Coleoptera, joining the Greek pteron, a wing, to koleos, meaning what?

Sheath describes the hardened forewings that fold over a beetle's back. Those tough cases set beetles apart from most other insects.

Which insects prepare a dead mouse or bird as a nursery, where both parents regurgitate flesh for their larvae?

Burying beetles fight over a carcass until one pair remains, then dig it into the soil to hide it from competitors. Care by both parents is rare among insects that do not live in colonies.

Bark beetles of the genus Scolytus carry the spores that cause which tree plague of Europe and North America?

Dutch elm disease is named not for where it began but for the Dutch scientists who identified it, starting with Bea Schwarz in 1921. Infected trees plug their own water vessels trying to stop the spread.

Which American author wrote The Gold-Bug, in which a scarab-like beetle leads to a pirate's buried treasure?

Edgar Allan Poe won a newspaper contest with the tale, and the $100 prize was probably the largest sum he ever received for a single work. Its code-breaking plot helped make cryptograms popular.

Which jewel beetle from Asia, first identified in Michigan in 2002, has killed tens of millions of North American trees?

The emerald ash borer does little harm in its native range, where it lives at low densities. In North America it threatens most of the continent's 8.7 billion ash trees.

The devil's coach horse, which raises its tail like a scorpion when threatened, belongs to which huge beetle family?

Rove beetles have wing cases so short that more than half of the abdomen is usually left exposed and free to flex. With tens of thousands of species, they are one of the largest families of any organism.

Melanophila beetles use infrared sensors near their legs to find which events, where they then mate and lay eggs?

Forest fires leave freshly burned wood, which is where these fire beetles lay their eggs. Their heat sensor is a specialised organ with extraordinary sensitivity to infrared radiation.

Which ancient flowering trees are thought to have evolved before bees existed, relying on beetles for pollination?

Magnolias still show the marks of that partnership, since their flowers are often damaged by the beetles that pollinate them. Beetles were most likely the first insects to pollinate flowers at all.

Longhorn beetles of the family Cerambycidae are named for which body parts, often longer than the rest of the insect?

Antennae as long as or longer than the body mark most of the family's species. Its members include the titan beetle, one of the largest insects known.

Christmas beetles, noisy and clumsy scarabs abundant in late December, are a summer sight in which country?

Australia's Christmas beetles belong to the genus Anoplognathus and are named for turning up, in town and country alike, close to the holiday. They grow 20 to 30 mm long.

The cockchafer, a scarab that swarms around treetops at dusk, takes its nickname from which month of its emergence?

May is when the adults emerge, giving the Maybug its name, and they live for only five to seven weeks. Their root-eating grubs first spend three to four years underground.

Once they become adults, the giant titan beetles of the Amazon rainforest give up which activity entirely?

Feeding stops for good once a titan beetle matures, though it will still drink water. The grubs are thought to do all the eating, inside dead wood, yet no scientist has ever identified one.

True weevils, the family Curculionidae, are most easily recognised by which feature of the adult's head?

A long snout, called a rostrum, carries the weevil's chewing mouthparts, and females use it to help lay their eggs inside plant tissue.

Ambrosia beetles tunnel into dead or dying trees not to eat the wood but to grow gardens of what?

Fungus is the only thing these insects and their grubs eat. When young adults leave home, they carry a supply in special pockets to start a garden in a new tree.

Vedalia ladybirds shipped to California in 1888 ended an outbreak of scale insects, saving which of the state's crops?

Citrus growers had only 514 of the imported beetles to start with, yet the scheme worked so well that it became a classic case of biological pest control.

The maquech, a live beetle decorated with rhinestones and worn on a tiny gold chain, is a tradition of which country?

Mexico's Yucatán Peninsula is where locals fix rhinestones and pearls to the backs of these ironclad beetles. They are now more often sold to tourists than worn.

In which Aristophanes comedy does an Athenian fly to the home of the gods on a giant dung beetle?

Peace won second prize at the City Dionysia in 421 BC, days before a treaty promised to end the Peloponnesian War. Its hero, Trygaeus, keeps his mount supplied with dung before take-off.

Ladybirds make up which beetle family, whose scientific name comes from the Latin word for scarlet?

Coccinellidae was coined by the French zoologist Pierre André Latreille in 1807. The bright colours behind the name warn predators that the insects' blood is laced with toxins.

The oldest known beetle, Coleopsis, lived about 295 million years ago at the start of which geological period?

Permian beetles are thought to have been wood-eaters, and most of those early lineages died out in the mass extinction that closed the period.

Which insect family includes the smallest members of the order Coleoptera, with some adults measuring only 0.3 mm?

Featherwing beetles are so small that air feels thick to them, which is why bristly, plume-like wings serve them better than ordinary flat ones.

Which Victorian actress played Lady Macbeth in a green gown sewn with 1,000 iridescent jewel beetle wing cases?

Ellen Terry wore the gown at London's Lyceum Theatre in 1888, and John Singer Sargent painted her in it the following year. The portrait belongs to Tate Britain.

About 90% of beetle species, including scarabs, weevils and ladybirds, belong to which of the order's four suborders?

Polyphaga means eaters of many things in Greek, a fair label for by far the largest of the four. Its members share small hardened plates in the neck that the other three suborders lack.

Gardeners welcome ladybirds because most species, as both adults and larvae, prey mainly on which common plant pests?

Aphids have fought back over time: under pressure from the beetles, some species have evolved to become more toxic to eat.

Beetles are found in almost every habitat on Earth but are largely absent from the polar regions and which other realm?

The sea is a rare gap for a group that otherwise eats plants, rotting debris and other small animals in nearly every setting on land and in fresh water.