From humble garden ladybirds to rainforest-dwelling titans, the beetle family includes some seriously impressive species
The rate at which the global human population continues to increase is a serious cause for concern to many scientists, but when it comes to sheer numbers we are firmly put in the shade by beetles. The world is crawling with them – there are about 400,000 species and counting. Accounting for around 25 per cent of all known animal life, each one is a member of the order Coleoptera. The name is derived from the Greek words koleos, meaning ‘sheath’ and pteron, which translates as ‘wing’.
Tiger beetles run blindingly fast to catch their prey
Tiger beetles are master assassins. From infancy to adulthood, these carnivorous critters are focused on the pursuit of prey, and they use various methods to catch it.
As larvae, the tiger beetle hides in a deep burrow and waits for passing insects to wander by, grabbing at creatures much larger than themselves to secure a meal. The hardy grubs are incredibly patient – they can go for weeks at a time without eating and can even survive floods.
The adult tiger beetle is a speed demon, capable of running down prey at velocities so fast that it temporarily becomes blind. This is due to the fact that its eyes don’t have time to collect sufficient photons to create an image of the beetle’s intended victim. Luckily, it has a handy pair of antennae to help it detect and avoid obstacles. It will also stop on occasions to reorient itself. A member of the same family, Cicindela hudsoni, is so fast that once body size is considered, a human would have to cover 200 metres in under a second to match it.
Titan beetles have jaws strong enough to tear into human flesh
Although they’re giants of the insect world, titan beetles are incredibly hard to find. That’s because these elusive bugs live deep in the thick rainforests of South America. Titans possess a fearsome set of jaws, which are strong enough to snap a wooden pencil in half and tear into human flesh. Thankfully, they’ll only bite if provoked, and they do warn their enemies with a loud hissing noise before attacking.
Intriguingly, titan beetles don’t eat as adults. Instead, they use stored energy that they gained while feeding as larvae. Titan grubs have never been seen, but they’re thought to be enormous – boreholes found on dead trees in their habitat suggest each baby bug could be up to a foot (0.3 metres) long!
Ladybirds bleed toxic blood
As insects go, ladybirds are pretty popular with humans. Most people enjoy seeing them, particularly gardeners, who revere this bright- coloured bug’s appetite for aphids.
Yet beneath the ladybird’s rosy carapace and apparently friendly demeanour lies a beetle that means business. Their red-and-black bodies aren’t merely for show – they’re a signal to predators not to mess with them. So why shouldn’t a bird eat this bug?
For one thing, ladybirds taste disgusting. Then there is the ladybird’s ability to emit a toxic fluid through the joints of its exoskeleton. When attacked by a predator the bugs squirt this foul alkaloid substance, sending their assailants flying in search of easier, tastier prey.
Bombardiers mix deadly chemicals inside their bodies
While you might think of chemical weapons as a human invention, insects have been using deadly substances to overwhelm their opponents for millennia. The bombardier beetle’s arsenal is a lethal testimony to this fact. These carnivorous creepy crawlies use a noxious chemical spray to destroy any insect foolish enough to attack them. The weapon works by combining two chemical compounds (hydroquinone and hydrogen peroxide) stored in the bombardier’s abdomen.
When the beetle feels under threat it opens a valve to combine the two substances, causing a chemical reaction that raises the temperature of the mixture to near boiling point. It then expels it powerfully through the abdomen with a loud popping sound. The spray irritates the respiratory system and frequently kills predators.
Some African bombardier beetles have the ability to direct their chemical spray with incredible accuracy, swivelling their abdomens to aim their natural weapons at a potential threat.