Five tricks to avoid sandfly bites this summer

Te Namu: the sandfly is an unwelcome summer guest.

They're as much a part of the NZ summer as beaches, baches and BBQs: bites from te namu or sandflies are unavoidable.

During warmer months the female flies feast on the blood of passers by, leaving some very painful bites. While in other parts of the world the tiny black flies transmit dangerous diseases the New Zealand species are 'harmless' but no less annoying.

There are no shortages of home remedies to avoid the blood-sucking insects. Solutions to ward them off include everything from eating extra Vegemite to rubbing exposed skin with banana peels. Once bitten, twice shy - hikers will go to extraordinary lengths to stop being bitten by the insects.

A more high-tech solution involved creating an app to track the density of sandflies around New Zealand.

Programmer Finnian Anderson said he came up with the idea for the Sandfly App while walking the Milford Track. "I was absolutely eaten alive," he told Radio New Zealand. "My ankles were so swollen, I couldn't get my boots back on."

Anderson's nerdy solution relies on bite victims reporting to the website.

This summer the West Coast, Fiordland and Central Otago are particularly busy with biting bugs he says.

However, the solution isn't perfect and relies on user input to get data. The heat map could be indexing thin-skinned Kiwis rather than sandfly bites.

Not everyone attracts the bugs, and some people have worse reactions to bites than others.

So, how do you avoid getting bitten by black flies in the first place?

Sandfly bites are a less welcome side to summer. Photo / Wikimedia Commons

Smell

According to studies by the London School of Hygiene & Tropical Medicine, certain smells attract blood-sucking insects. Professor James Logan is working on developing repellents to pests using "strong scientific research help control and prevent the spread of diseases like malaria".

Research has shown that mosquitoes and black flies have a taste for things other than human blood. Namely, very smelly cheese.

Limburger and Blue cheeses which use similar bacteria found in skin are shown to attract the insects. The compounds - and smells - produced by the cheeses are indistinguishable from human sweat which can attract biting insects.

You might want to avoid fromage, or at least change your smelly socks between walks!

Exercise

Take it easy!

Black flies have been shown to be attracted by sweat and carbon dioxide expelled in walkers' breath. While huffing and puffing away with strenuous exercise on a trail, you're sending out signals that sandflies are looking for.

Lactic acid produced by tired muscles has been proven to attract mosquitoes looking for blood.

Try hard trampers will only be rewarded with more bites.

Diet and alcohol

There may be some truth in the home remedies against bites. Bananas, vinegar and other common ingredients have been shown to be mild repellents. They can at least mask some of the signals that attract the blood-sucking bugs.

One study in Burkina Faso showed mild correlation between blood alcohol and the receptivity to mosquitoes.

The small study claimed that "beer consumption increases human attractiveness to malaria mosquitoes".

Lay off the beers if you don't want to be bitten.

Genes

It's no secret, some people are more attractive to fly bites than others.

Research by the Arctec lab at the London School of Hygiene & Tropical Medicine are looking at the possibility that bites could be down to genetic traits.

They are working to isolate genes that are shown to attract, or possibly repel mosquitoes as a future gene-based preventative for insect bites.

While you can't choose your genetic makeup you can choose your company.

The easiest way to avoid being bitten is to go walking with someone more appealing to sandflies than you.