Every year this insect emerges to defoliate eucalyptus and delight with their festive colours. But their numbers seem to have crashed in recent years.

Would you be able to identify a Christmas beetle?

Common name: Christmas beetle, washerwoman or king beetle (for some species)

Scientific name(s): Anoplognathus spp., Family Scarabaeidae. Anoplognathus pallidicollis is the most common species in Eastern states.

Description: Christmas beetles are large, slightly flattened metallic brown, yellow, green, or pink beetles up to 3 cm long. They have clubbed antennae and large dark eyes. Their bodies are mostly smooth, with numerous small pits in rows down the wing covers. Legs are prominently clawed, and covered in numerous barbs. Individual species can be identified by colour and examining the hair on their behinds.

Geographic distribution: 36 species, almost all Australian, but a handful in South Africa as well.

Habitat:  Christmas Beetle larvae live underground for 7 to 18 months, initially feeding on soil and decaying plant material, and feeding on grass roots, emerging as adults after spring rain in November and December to mate. The adults feed on eucalyptus leaves. They are clumsy, noisy fliers (usually flying at night) and are attracted to lights, sometimes entering houses. The adults are most active after sunset.

Pest status: The larvae, if numerous, can damage the roots of turf, crops, and pasture, leaving yellowed patches. Some species are pests in eucalyptus plantations as adults, and they were once so common they would bend tree branches under their weight, and wash up in their millions in Sydney Harbour.  Habitat loss and unseasonally dry springs are greatly reducing their numbers, especially in urban areas.

Treatment: No chemical treatment recommended, in urban settings, because of the risk of poisoning birds and other animals that eat the beetles, and the impracticality of spraying large trees. If swarms are defoliating small backyard trees, they can be blasted off with a hose, or shaken off onto a sheet, and humanely killed by freezing. Turning of exterior lights and closing blinds will also reduce the number of adults attracted to a house.

Daniel Heald, technician and entomologist.