Most insect bites in Australia come from mozzies, biting midges (often called sandflies), march flies, bed bugs and ants, and healthdirect says most get better in a few days. The quickest clue to what bit you is where you were and when. Wash the spot, use a cold pack, then cover up and use repellent next time.
Summer here is made for being outside: a dawn swim, a creek picnic, a long evening on the verandah. This guide helps you sort out a bite quickly and get back out there.
Which insects bite in Australia?
Good news first: the Australian Museum says the majority of insects in Australia are not harmful to humans, and some bite or sting only if threatened. healthdirect lists ants, bees and wasps, mosquitoes and bed bugs among the insects that bite or sting. Midges, march flies and mosquitoes are all biting flies.
Spiders, ticks, centipedes and leeches are not insects (healthdirect, Australian Museum). Spiders sit outside this guide; healthdirect says the Poisons Information Centre on 13 11 26 gives advice on bites and stings.
Bees, wasps and many ants sting rather than bite. Either way, healthdirect says bites and stings may cause pain or a burning feeling, swelling, redness, itch or blisters.
What bit me? Australian insect bites identification by where you were
Most guides go insect by insect, but you remember the moment: "I was at the beach at sunset and saw nothing." So this types of bug bites chart starts with where you were and when.
| Where and when | Likely biter | What you notice | First step | Read more |
|---|---|---|---|---|
| Beach, estuary or mangroves at dawn or dusk, calm air | Biting midges, often called sand flies (WA Health) | Often unseen; itching may not start for several hours (WA Health) | Soap and water, cold pack wrapped in a cotton cloth (healthdirect) | Midge bites guide |
| Calm, sunny day by a creek, beach or estuary | March fly (HealthyWA, nib) | A painful bite (HealthyWA) you feel as it happens (nib) | Ice pack or a mild antihistamine (HealthyWA) | March fly section |
| Evening on the verandah or near still water | Mosquito (healthdirect) | Red, swollen lump a few minutes to a few hours later, then itchy (healthdirect) | Soap and water, ice pack in a cloth for 15 minutes (healthdirect) | Mozzie section |
| Woke up with bites after a night away | Bed bugs (healthdirect) | Red, itchy spots up to 2 cm, often on arms and shoulders (healthdirect) | Check the bedding and mattress stitching (healthdirect) | Bed bug vs mosquito bites |
| Bushwalk or long grass on the east coast | Tick, an arachnid, not an insect (healthdirect) | A tick on your skin (healthdirect) | Freeze it with an ether-containing product; do not squeeze (healthdirect) | Tick section |
| Gardening or bare feet on the lawn | Ants, bees or wasps: stings (healthdirect, Australian Museum) | A bee stinger may be visible in your skin (healthdirect) | Scrape it out with a fingernail or card (healthdirect) | Stings section |
Mozzie bites
healthdirect says there are more than 350 species of mosquitoes in Australia, but only some bite people, and only females bite. They find you by the smell of your skin, your body temperature and the carbon dioxide you breathe out.
Mosquito bites cause a red, swollen lump that can appear from a few minutes to a few hours after the bite, then becomes itchy and may be painful (healthdirect). The reassuring part: most mosquitoes in Australia don't carry germs that cause disease. healthdirect's self-care is soap and water, an ice pack wrapped in a towel or cloth for 15 minutes, and antihistamines to ease the itch. It also says to see a doctor urgently if a rash, fever or chills, headache, joint or muscle pains or fatigue follow a mosquito bite, as these can be signs of a mosquito-borne disease such as Ross River virus.
For repellent types and how to use them here, see our guide to choosing an insect repellent in Australia.
Midge and sandfly bites
Bitten but can't see anything? WA Health says biting midges are commonly, but incorrectly, called sand flies. At 1 to 3 mm they are so small they often go unobserved, and itching may not begin for several hours. They are most active in calm conditions around dawn and dusk, near sandy estuaries, foreshores and mangrove swamps in WA. Bites may blister, become weepy and persist for days or weeks, and WA Health says midges are not known to transmit any human diseases in Australia.
Our midge bites guide goes deeper, and our sandfly repellent planner covers the beach bag. In the US, the same family is called no-see-ums.
March fly bites
HealthyWA describes march flies as stout-bodied flies, 6 to 25 mm long, with very large eyes. More than 200 species live in Australia, also known as horse flies or tabanids. Dr Hamish Black, writing for nib, puts them at up to 3 cm.
HealthyWA says adults are most active in daylight in warm weather, especially on calm, sunny days, and in the tropics they may stay active through the drier winter. nib names beaches, creeks and estuaries as their habitat.
nib says march fly bites hurt a fair bit, so you will be aware of the bite as it happens, while mosquito bites often go unnoticed. March flies take a moment to settle before they bite, so swat them away. HealthyWA says they are not known to transmit diseases to humans or livestock in Australia, though the bite can cause allergic reactions in some people. For relief it suggests an ice pack or a mild antihistamine, and warns that scratching can lead to infection.
Why do march flies bite?
HealthyWA says the females of most species take a blood meal after a painful bite with their piercing mouthparts, and can be annoyingly persistent. Adults of both sexes feed on nectar and plant juices. Two tips: avoid blue and other dark colors, which attract march flies, and avoid tight clothing, which they can bite through.
Bed bug bites
healthdirect says bed bug bites can cause red, itchy spots up to 2 cm, most often on exposed skin such as arms and shoulders; on black or brown skin they may look purple and be harder to see. As many as 1 in 5 people do not react, and others may not notice a reaction for up to 9 days. They are not known to spread disease. If you think you have them, healthdirect says to call a licensed pest management company. Our spray is not a bed bug treatment. More in how bed bug bites differ from mosquito bites.
Ant, bee and wasp stings
These are stings, not bites. healthdirect says that if a bee stings you, you may see the stinger in your skin; scrape it out with the edge of a fingernail or something like a credit card. Wasps and bull ants rarely leave their sting behind. Not all ants have stings, but bull ants and jack jumpers do (Australian Museum). healthdirect says to leave insect nests alone, cover food and drink, and clean up sticky spills quickly.
healthdirect says that if you think someone is having anaphylaxis after a bite or sting, use their adrenaline autoinjector straight away if they have one, then call triple zero (000) for an ambulance.
Ticks (not insects, but a summer bushwalk question)
healthdirect says ticks are arachnids with 8 legs, especially common along the east coast, where most tick bites come from the paralysis tick, Ixodes holocyclus. Kill a tick as soon as possible by freezing it with an ether-containing product, and do not squeeze, agitate or forcibly remove it. If the tick does not drop off, or can't be frozen, leave it in place and get urgent medical help.
To avoid them, healthdirect suggests tucked-in long sleeves and trousers, light-colored clothing, a repellent with DEET, picaridin or lemon eucalyptus, and 20 minutes in a hot dryer for your clothes afterwards.
What helps, as healthdirect words it
- Wash the area with soap and water
- Apply a cold pack wrapped in a cotton cloth
- Take pain relief
- For ongoing swelling or itching, take antihistamines for up to 3 days (available at a pharmacy without a prescription)
- Speak with your pharmacist for advice
healthdirect says to see your doctor if your bite or sting does not get better after a few days or it looks infected; infected skin becomes warm, red and painful to touch.
How to avoid insect bites this summer
Australian summer, December to February, is when most of these insects are out. An easy routine:
- Cover up in loose, long, light-colored layers, with socks and shoes. Skip perfume outdoors.
- Mind the time. Midges and mozzies are busiest around dawn and dusk.
- Use repellent evenly on exposed skin.
- Screen it out. WA Health says midges can fit through standard fly screens, so use fine mesh on doors, windows, caravans and tents.
- Keep air moving. WA Health says ceiling fans may discourage midges from biting.
- Tidy the yard. healthdirect suggests mowing lawns and emptying anything that holds water, such as buckets and paddling pools.
Where plant-based PMD fits
Each source in its own words:
- HealthyWA (march flies): DEET, picaridin or oil of lemon eucalyptus, which HealthyWA notes is also known as PMD.
- healthdirect (mosquitoes): the best repellents contain DEET, oil of lemon eucalyptus or picaridin.
- WA Health (midges): names DEET or picaridin, and says "Natural or organic repellents are generally not as effective as DEET or picaridin and may need to be applied more frequently."
- nib (march flies): natural remedies provide limited protection.
Our own Bloc Off Spray is built on 8% plant-based PMD (para-menthane-3,8-diol) derived from lemon eucalyptus. Our co-founder and formulator Cassidy Huang and I spent two years with a Taiwan-based chemist on the formula. It is water-based, DEET-free and alcohol-free, with aloe vera and chamomile, in a 4 oz (118 ml) bottle, and our product page lists 6+ hours of lab-tested protection against mosquitoes. Here we discuss it for mozzies only: we make no march fly, midge, tick or bed bug claim for it. We ship to Australia.
Your summer day-out kit
- Long, light, loose layers
- Repellent for exposed skin, plus Bloc Off Wipes (10 individually wrapped) for the beach bag
- A cold pack in the esky
- Antihistamine from the pharmacy in the day bag
- A fan for the verandah
- Fine mesh on the caravan or tent
Then go and enjoy the long summer evenings outside.
FAQ
How do I identify what bit me in Australia?
Start with where you were and when. Unseen biters near the water at dawn or dusk suggest midges (WA Health). A bite you felt straight away on a sunny day suggests a march fly (nib). Bites after a night away may be bed bugs, often on arms and shoulders (healthdirect).
What is biting me but I can't see any bugs?
Usually biting midges. WA Health says they often go unobserved, and itching may not start for several hours.
Why do march fly bites hurt so much?
HealthyWA says females inflict a painful bite with piercing mouthparts to take a blood meal, and nib says you will be aware of the bite as it happens.
How long do insect bites last?
healthdirect says insect bites and stings usually get better in a few days. WA Health says midge bites can persist for days or weeks.
Which insect repellent works on march flies?
HealthyWA recommends DEET, picaridin or oil of lemon eucalyptus (OLE, which it notes is also known as PMD) on all exposed skin. nib says natural remedies provide limited protection.
Written by Tanya Lee, Co-Founder of The Superbloc. Sources: healthdirect (Insect bites and stings; Mosquito bites; Bed bugs; Tick bites), WA Health (Biting midge), HealthyWA (March flies), the Australian Museum (Insect bites and stings), and nib (Spotting and treating a march fly bite, with Dr Hamish Black).