Houseflies can take off five times faster than other flies

Houseflies are so difficult to swat because their wings let them take off five times faster than other flies.

A newly discovered specialisation in the wings of the common household invader has proved why they are so hard to pin down.

The housefly’s wings, combined with their vision, make it easier for them to escape attempted fly swats by rolled up newspapers and other incoming hazards.

Experts discovered this new mechanism on houseflies, blowflies and other members of the family known as calyptratae.

The discovery was revealed by researchers from Case Western Reserve University in Ohio for the journal Proceedings of the Royal Society B: Biological Science.

All fly species have shortened hindwings called halteres which are not used to generate lift, but are sensory organs used for balance to help with stability while in flight.

However, among calyptrate flies these hindwings are rhythmically moved when standing still and, upon closer examination, are found to aid a speedier take off.

Leader of the study, Alexandra Yarger, said: "We know that they're the only group that does this. It's still a bit of a mystery why they do it."

The finding that calyptrate flies are up to five times faster at taking off than other flies was seen using high-speed cameras to film the flights of more than 20 fly species.

The typical take-off time for a housefly was 0.007 seconds or 7 milliseconds, enough for one wing beat.

By comparison, other species of flies took four wingbeats over 0.039 seconds or 39 milliseconds to take off.

Upon removing the halteres, the team found that both speed and stability of take-offs reduced in calyptrate species.

Miss Yarger explained this haltere movement increases the amount of sensory information houseflies receive, but what they can sense and how it is processed remains unclear.

She said: "We think there might be a pathway from halteres to the legs that's causing them to take off faster. It doesn't go through any central nervous system, it's almost like a reflex."

This speedy take-off allows houseflies to avoid harm much better than other flies.

Jessica Fox, study co-author, said: "Escaping very quickly is part of the reason they are so successful.

"Transitioning from taking off to flight is a challenging thing and using halteres to help both is clearly very advantageous." END