Some of this is not breaking news, but some is. When I was watching someone in another classroom in futile pursuit of said dastardly, dirty diptera, I realised that there is a lot of interesting science behind successful swatting.
Flies are hard to swat for a number of reasons. They avoid predation by both sensory detection and behavioral responses. With its large eyes, a fly can see nearly 360°, including behind itself. This means that it’s nearly impossible to “sneak up” on a fly. Because an insect’s flicker fusion frequency is 250 Hertz or more (compared to the human 50), they are vastly more sensitive to motion. Flies can see a flyswatter coming at them, no matter how slow or fast you move it. As anyone who has ever examined their prey has noted, flies are also hairy. These “hairs” (setae) make them sensitive to changes in ambient air speed and direction — they can feel the acceleration of the air from the pressure wave created by the flyswatter.
Michael Dickinson and others at the California Institute of Technology have recently teased out other details to the flys’ success. They used high-speed imaging to discover that flies will make changes in their body position (including limb angles) upon seeing the swatter. These adjustments enable flies to take off at the appropriate escape angles when they leap into the air. Dickson’s advice to fly killers is to aim the swatter to where the fly is going, rather than where it is. This is of course good advice, but (unlike the details of fly posture) not breaking news to anyone who has hunted moving targets, whether shooting ducks, netting dragonflies, or intercepting soccer balls.
My own advice is slightly different, as it was built upon behavioural observations from several years ago.
Firstly, one can halt (though not immediately kill) a fly in mid-flight by fouling up its airstream. This involves using not a flyswatter, but a piece of fabric, such as a kitchen towel or piece of random laundry from the washbasket or bedroom floor (you know who you are). You’re still trying to hit the fly, but instead of “snapping” it with a whip action, you’re trying to knock it out of the air. The stunned fly plummets to a horizontal surface where you can quickly squish it with a tissue.
Secondly, one can outright swat a fly that has (finally!) chosen to land somewhere. I usually do this with both hands, which naturally requires one to get over the learned repugnance of touching a fly. (But hey, we do have soap and running water, right?)
Now, we already know that the fly can see you coming, and can feel you coming. Neither stealth by flyswatter speed nor approach angle will work. What I do is to pluck a tissue from the box, set it nearby, and then “bookend” the fly by framing open hands (with fingers closed together) on each side of it. I’m not trying to swat the surface (which then necessitates waiting for the fly to land on something both hard and washable), but rather the airspace several inches/ centimeters just above the surface.
When I clap my hands together, it doesn’t matter which direction the fly is positioned to take off — it’s still caught between my hands. Because I have bony fingers, sometimes the fly is caught in the pocket between the base of two fingers and my palm, but a slight twist of my hands in opposite directions is sufficient to do the pest in. It’s not necessary to reduce the fly to a messy smear — just enough pressure to break the wings is enough to disable it so you can deliver the killing crack while picking it up with the tissue.
Having then rid the room of the rambunctious irritation, I then go to wash my hands of the whole affair.