Why Christmas Beetles Swarm Your Home in Summer

Christmas beetles swarm homes in summer because warm rain softens the soil and triggers a mass emergence of adult beetles. The beetles then fly towards house lights and nearby gum trees to feed and find a mate. They are harmless native insects, and the swarms usually ease off within a few weeks.

If you live on the Gold Coast, in Brisbane or around Northern NSW, you have probably heard them before you saw them. First comes a heavy thud against the window screen on a warm December night, then another, then a dozen glossy beetles are crawling over the patio light. For many Queenslanders they are as much a sign of the season as the first summer storm.

Our technicians at Pest-Ex field plenty of calls about Christmas beetles every year. Below we explain what they are, why they turn up at your house in such numbers and what to do about them. We also cover the summer pests that genuinely do need attention.

What are Christmas beetles?

Christmas beetles are native Australian scarab beetles from the genus Anoplognathus. There are more than 30 species, mostly found along the east coast. They get their common name from appearing in late November and December.

Adults are chunky, oval beetles roughly 15 to 30 millimetres long. Their shells are usually golden brown, amber or green, often with a metallic sheen. Their legs have small hooks and spines, which is why they cling so stubbornly to flyscreens, clothing and curtains.

Most of their life is spent underground. The larvae, known as curl grubs, are fat, cream-coloured grubs that curl into a C shape. They feed on grass roots and decaying plant material in the soil. After months below ground they pupate, and the adults emerge in a short burst during early summer.

Why do Christmas beetles swarm homes in summer?

The swarms around your house come down to four conditions lining up at once.

Summer rain sets off the emergence

Adult beetles wait in the soil for the right moment to dig out. Heavy rain after a dry spell softens the ground, so huge numbers emerge over just a few nights. That is why sightings often spike after the first big storms of the season in South East Queensland.

Lights pull them towards your house

Christmas beetles are mostly active at dusk and through the night, and they are strongly drawn to artificial light. Porch lights, bright windows and garden floodlights act like a beacon. Being clumsy fliers, they bump into walls and glass, drop onto decks and end up crawling around doorways.

Gum trees give them food nearby

Adult Christmas beetles feed on eucalyptus leaves. Homes in leafy suburbs, near bushland or with established gums in the yard tend to see the biggest numbers, because the beetles have food right next door.

It is mating season

The adults only live for a few weeks, and that time is spent feeding and breeding. Swarming flights help males and females find each other. Females then lay eggs in lawns and garden soil, and the cycle starts again for next summer.

When are Christmas beetles most active in South East Queensland?

Across the Gold Coast, Brisbane and the Northern Rivers, Christmas beetles usually appear from late November. They peak through December into early January, and you will notice them most on warm, humid evenings after rain.

Numbers vary a lot from year to year. A wet spring and early summer can produce a big season, while a dry run can mean very few. Entomologists have also noticed that Christmas beetles are less common than they were a few decades ago, likely linked to the loss of native trees and grassland as suburbs grow. Researchers run a citizen science count each summer through the iNaturalist app, so logging the beetles you see helps track their numbers.

Are Christmas beetles harmful?

No. Christmas beetles do not bite or sting, they do not carry disease and they will not damage your house. The worst most people experience is a scratchy grip from their spiny legs, or a fright when one flies into their face.

They are also harmless to dogs and cats, although a pet that eats several might get a mild upset stomach.

In very large numbers, adult beetles can strip leaves from young eucalypts, and curl grubs can thin out patches of lawn. In most home gardens this damage is minor, and plants recover once the season passes.

Because they are native and pose no risk to people or buildings, Christmas beetles do not need a pest control treatment. The better approach is to make your home less attractive to them for a few weeks.

How to keep Christmas beetles away from your home

A few simple changes will cut down the number of beetles gathering around your doors and windows:

• Switch off outdoor lights you don’t need on warm evenings, especially porch and patio lights.
• Use warm-toned or yellow globes outside, since night-flying insects are less drawn to them than to bright white light.
• Close curtains and blinds after dark so indoor light doesn’t spill outside.
• Check flyscreens on doors and windows and repair any tears or gaps.
• Keep doors shut in the evening while lights are on inside.
• Move beetles outside gently by hand or with a container, then release them near trees or garden beds.

Avoid spraying insecticide on them. It is unnecessary, harms a native species and can affect beneficial insects in your garden.

Is it a Christmas beetle or something else?

A few other insects show up around lights in summer and are easy to confuse with Christmas beetles.

Rhinoceros beetles are much larger, dark brown to black, and males have a distinctive horn. They are harmless and also appear after summer rain.

Lawn scarabs, including the introduced Argentinian lawn scarab, are smaller, plainer brown beetles that also gather at lights. Their grubs are a common cause of lawn damage.

Flying termites are the one lookalike swarm to take seriously. On warm, humid evenings after storms, winged termites leave mature colonies to start new ones, and they are also attracted to lights. They are much smaller than beetles, with soft bodies and two pairs of long, equal-sized wings that they shed soon after landing.

If you find small winged insects or piles of discarded wings around windowsills, read our guide to flying termites and what they mean for your home. Then consider booking a professional termite inspection, because a swarm near your house means an active colony is close by.

Other summer pests that arrive with the same conditions

The heat, humidity and storms that bring out Christmas beetles also drive other pests indoors, and these can be a real problem:

• Ants move inside looking for food and water, especially around storms. Our ant control service targets the nest, not just the trail you can see.
• Cockroaches breed quickly in summer heat, and some species fly on warm nights. See our tips on keeping flying cockroaches away in summer, or arrange cockroach treatment if they are indoors.
• Spiders follow the insects gathered around your lights, so a porch full of beetles often means more spiders on the walls. Our spider control helps keep numbers down around entry points.
• Mosquitoes breed in standing water after rain, and our mosquito treatment reduces breeding around your yard.

Hosting family over the holidays? Our guide on keeping pests away at Christmas has more practical steps.

When should you call Pest-Ex?

You don’t need a pest controller for Christmas beetles. It is worth calling if you notice:

• winged insects or shed wings inside the house, which could point to termites
• cockroaches, ants or spiders indoors that keep coming back
• mud tubes along walls, footings or timber around your home

Pest-Ex has protected homes across the Gold Coast, Brisbane, the Sunshine Coast, Logan, Tweed Heads and Northern NSW since 2006, and is part of the Rentokil group. Our technicians use Termatrac radar and FLIR thermal imaging to find termite activity hidden inside walls. Visit our Gold Coast or Brisbane pages, call 1300 915 743, or book online to arrange an inspection.

Frequently asked questions

Why are there so many Christmas beetles on the Gold Coast this summer?

Big seasons usually follow good spring and early summer rain, which softens the soil and lets large numbers of adults emerge at once. Leafy suburbs close to bushland and gum trees, common across the Gold Coast hinterland and northern suburbs, tend to see the most.

Do Christmas beetles bite people in Brisbane?

No. Christmas beetles have no stinger and do not bite people. Their legs have small hooks that can feel scratchy on skin, but they are harmless.

How long do Christmas beetles stay around in Queensland?

Adults live for only a few weeks. In South East Queensland, most swarms appear from late November and fade by mid to late January.

Should I spray Christmas beetles around my house?

There’s no need. They are native, cause no harm to people or buildings, and leave on their own. Turning off outdoor lights and closing screens is the most effective way to reduce numbers.

How can I tell flying termites from Christmas beetles at my lights?

Christmas beetles are hard-shelled, rounded and around thumbnail size or larger. Flying termites are small, soft-bodied and have four long wings of equal length that drop off soon after landing. If you see discarded wings around doors and windows, arrange a termite inspection.