Intriguing insect facts

Insects are everywhere, all the time, every day of the year. We might not see them on a daily basis, but they are still somewhere. They could be underground, in the sky or anywhere in between. Insects are permanent inhabitants of every continent on Earth. Read on to explore some intriguing insect facts from Dominic Couzens and Gail Ashton’s new book An Insect A Day.

By Dominic Couzens and Gail Ashton

Madagascar Hissing Cockroach

Gromphadorhina portentosa | Hemiptera / Blaberidae

It’s a remarkable fact that a generally derided insect (a cockroach) from the forest floor leaf litter on the island of Madagascar should become world famous. But it’s true. The hissing cockroach is kept as a pet around the world and has even featured in movies. The reason is down to one thing: it hisses. And not many insects hiss.
One of the world’s largest cockroaches, it makes its unusual sound by expelling air through specialized spiracles, the main respiratory organs of land insects. It’s a bit like the deflating of a tyre puncture. It is used primarily as a form of self-defence against predators.However, male cockroaches also have two other types of hiss. One is to put other males in their place. The other is an invitation to females.

Hitchhiking Wasp Larvae

Hymenoptera / Eucharitidae

The tiny Eucharitid wasp is a parasite of ants that live underground – not easy to reach, but this is a wasp with a plan. Eggs are laid into the leaf tissue of a plant frequented by the host ant, then the larvae (planidia) hatch out and hop on to passing worker ants and hitch a ride back to the nest. Eucharitid planidia are particularly motile and have a harder exoskeleton than most larvae, allowing them to pull off this hitchhiking stunt, known as phoresy. Once inside the nest, they drop off the workers and latch onto the ant larvae. Here, things get a bit dark, as the planidia eat away at the ant larvae, very carefully, avoiding critical organs and tissue; this keeps the host alive and fresh longer. Amazingly, the ant larvae survive being partially eaten, and is even able to pupate. The wasp itself pupates, and either exits the nest on its own, or leaves in the manner it came, just hitching a ride.

Metallic Stag Beetle

Cyclommatus metallifer | Coleoptera / Lucanidae

There are impressive stag beetles in Europe and the USA, but for sheer star quality, both are outshone by this extraordinary beetle from Indonesia. It comes in two colour forms, gold (which is the most common) and black, which naturally arise in both wild and captive populations. The males bear the outsized mandibles, which are used in combat over females. Well-matched males indulge in gladiatorial combat, jostling with their mandibles and trying to bite one another, with an end game of throwing your rival off the log or branch on which you are competing.

Leaf-roller Fly

Trigonospila brevifacies | Diptera / Tachinidae

Parasitic flies may not sound particularly endearing to most people, but here’s one that surely cannot fail to charm. The leaf-roller flies (trigonospila spp.), found in Australia and New Zealand, are snazzily striped species with crisp black and white (or pearly) horizontal bands, making them look like tiny, walking pedestrian crossings. These enigmatic flies are thought to parasitize leaf beetles (chrysomelidae) and for this reason are seen as beneficial biological control.

Sloth Moth

Bradypodicola hahneli | Lepidoptera / Pyralidae

The name says it all: sloth moths do indeed live on sloths. Bradypodicola hahneli lives in the hair of just one species, the pale-throated three-toed sloth (Bradypus tridactylus). Up to 100 individuals may piggyback on a single individual and can easily be seen running around the fur.

Nobody knows yet what the adults feed on, but there is no doubt what the larvae relish – sloth dung. The peculiar mammals are famous for defecating once a week, and while they do this, the moths fly down and lay eggs on the faeces. Once a sloth returns to the latrine, freshly emerged adult moths fly up and take up their unusual residence.

Dung Beetles

Coleoptera / Scarabaeidae

World Toilet Day on 19 November highlights the need for clean sanitation for everyone, all over the planet. There is much poo in the world, and it has to go somewhere. For animals that don’t have sewage infrastructure, this is dealt with in other ways. Since the first animals started to poo, a niche became available which has been filled by a host of invertebrates, bacteria and fungi that have evolved the ability to extract nutrients from dung, that cannot be absorbed by larger animals. Most well known are the dung beetles, which roll poo into almost perfect spheres. They collect the dung of large herbivores, pressing and forming it into balls and roll them back to their subterranean nurseries for their larvae to feast upon. All over the world, at any one time, millions of insects are consuming poo from every species (including, yes, humans); if they weren’t, we’d all be literally up to our necks in poo.

We hope you’ve enjoyed these fascinating insect facts. Find more stories of insects in An Insect A Day by Dominic Couzens and Gail Ashton, out now.