What is a beetle?
Beetles belong to the insect order Coleoptera. This name, from the Greek for ‘sheath’ and ‘wing’, refers to their hard front wings, which enclose the body. These are called elytra, and give beetles their distinct appearance. The elytra protect beetles from predators, and when they are digging amongst leaves or wood.
New Zealand’s beetles
New Zealand has 4,500 known beetle species, and there are probably many more yet to be discovered. Most can be found nowhere else.
The longest is the giraffe weevil – with its long head, it reaches 9 centimetres in length. Huhu beetles are also large, and their grubs were a tasty food for Māori. Among the smallest, at only half a millimetre long, are the feather-winged beetles.
Most beetles have a similar life cycle. The female lays eggs, which hatch into larvae or grubs. A larva’s body may be soft or hard, and it eats until it becomes a pupa. During this stage, its shape changes entirely, and it emerges as an adult beetle. Most can fly, although some cannot.
Most beetles eat plants – leaves, wood, grass and bark. Some prey on other insects.
Where they live
Beetles live throughout New Zealand, from the coast to the mountains. The greatest variety can be found in the forest – in trees, on the ground, under the soil or in rotting logs. A few can swim in hot springs, and some live deep in caves.
Beetles, especially flightless ones, are easily killed by introduced animals such as rats and cats. Some beetle species have become extinct. A reserve has been set up in Central Otago to protect the rare Cromwell chafer beetle, which is found nowhere else.
Beetles that are pests
Grass grubs are pests in New Zealand – by eating the roots of grass, they destroy farmland.