Insect expert Dr Jessica Stokes has revealed that house flies invading British homes can be caught by hand by approaching them slowly from above.
The method relies on exploiting the natural escape instincts of flies, which automatically shoot straight upwards whenever they detect a sudden movement or a change in air pressure.
Rather than aiming directly at the surface where an insect is resting, householders are advised to target the empty space a few inches higher. When startled, the fly launches upward into closing hands, where it can be held safely before being released outside without the need for swatters or chemical sprays.
Dr Stokes, a Project Officer and Fellow of the Royal Entomological Society, said house flies possess exceptional vision that makes traditional swatting difficult.
"Most house flies have very good eyesight, particularly when it comes to movement," Dr Stokes said. "The advice is therefore to approach them slowly, ideally from above."
She added: "Flies will almost always fly upwards, which is why many traps are designed a little like a lobster pot hanging vertically."
The Royal Entomological Society, founded in London in 1833, is a scientific organisation dedicated to insect research and public education.
Warm weather and fly numbers
Warm and humid weather across Britain has sparked concerns among homeowners who feel their kitchens and living rooms are being hit by a summer fly epidemic.
Dr Stokes explained that higher summer temperatures speed up insect development. This allows species to complete their life cycles faster and reproduce in far greater numbers.
As residents throw open doors and windows to cool down their houses during warm spells, insects find easy access indoors.
Fruit flies thrive in warm, humid conditions. They rapidly target kitchen fruit bowls, sinks, drains and compost caddies in search of food and breeding sites.
Despite being an unwelcome presence indoors, experts stress that flies perform crucial ecological roles outdoors as decomposers and pollinators, breaking down organic waste and recycling vital nutrients back into the soil.
"Insects often get a bad reputation, but the reality is much more interesting," Dr Stokes said. "Insects are quietly doing some of nature's most important jobs."
"Our aim is to help people understand them a little better and find simple ways to keep them out of our homes while allowing them to thrive outdoors, where they pollinate plants, break down organic matter and provide food for countless other species," she added.
Natural fly deterrents and home prevention
To deter flies from entering living spaces, Dr Stokes recommends placing citrus peel around problem areas. Insects find the natural fragrance emitted by the peel overwhelming.
Peppermint oil is also effective at overwhelming insect senses and masking the food odours and scent trails flies rely on to navigate.
Homeowners can mix a few drops of peppermint oil with water in a spray bottle to treat doorframes and windowsills, or place cotton balls soaked in neat oil in key problem spots.
"This will need topping up every few days as the scent fades," Dr Stokes said.
Further advice comes from Dr Erica McAlister, Principal Curator for Diptera and Siphonaptera at the Natural History Museum and Honorary Fellow of the Royal Entomological Society.
Dr McAlister noted that flies frequently venture indoors to escape intense summer heat outside. Diptera is the scientific order encompassing true flies, while Siphonaptera covers fleas.
She suggested installing physical barriers, such as hanging bead screens over open doorways, to block flies before they enter. The Natural History Museum in London houses tens of millions of biological specimens and leads international scientific research.
"I am a shooer," Dr McAlister said. "I coerce them outside by waving, but I understand if there are a lot this may be problematic."
"So you could catch them in pots by moving very, very slowly," she added.
