Why Are Houseflies So Hard To Kill? Frustrating Pest

by Derrick | Last Updated: February 15, 2022

Houseflies can be a pesky annoyance or a serious problem, depending on the circumstances. If allowed to crawl on food or sterile surfaces, flies can introduce disease and filth, making it important to rid your house of them. If you’ve ever tried to kill a fly Karate Kid style, however, you might be wondering why houseflies are so hard to kill.

Houseflies are so hard to kill because of their size, aerial agility, speed, and heightened visual awareness. Despite having nearly microscopic brains, flies coordinate their 270-degree vision and hindwing halteres to evade sudden threats while they’re in flight or on a surface.

A fly buzzing against your window or around your food can be infuriating, especially if you’ve been trying to kill it for a while. By understanding why they’re hard to kill, you’ll be better equipped to rid your home or workspace of houseflies. Keep reading for more information about what makes houseflies hard to kill, as well as a few home remedies for flies that seem uncatchable.

Flies Have 270-Degree Vision

Flies have 5 eyes, 2 of which are compound eyes. The other 3 eyes are simple eyes shaped like triangles, which are used for navigation. This system of simple and complex eyes gives flies a rough visual radius of 270-degrees around their body.

While their visual scope is very wide, flies still have poor eyesight. 

Flies are incapable of seeing clearly beyond 40” (101.6 cm) and have 6 blind spots, similar to the blind spots experienced by fighter pilots, according to Mexico News Daily.

The combination of vague area awareness and pin-pointed directional sight allows flies to watch a room for threats and make an efficient escape, according to Business Insider India. The compound eyes allow flies to keep a visual on a wide area without moving their heads, which helps to keep their directional vision stabilized.

Flies Are Natural Aerial Acrobats

Some flies can change direction mid-air in less than a hundredth of a second. This aerial speed and agility are attributable to their ability to flap their wings roughly 200 times per second, as well as their stabilizing halteres.

The brains of fruit flies, which are similar to houseflies, have been studied by the Howard Hughes Medical Institute at a nanoscale level. The results of that study showed that flies have the ability to learn and remember, which may also contribute to their ability to maneuver effectively in flight.

The ability to change direction on a dime while mid-air makes flies additionally difficult to kill, as they can assess and react to new threats with split-second timing. 

If you’re hunting flies with a flyswatter, even if you make contact, the fly’s ability to change direction as soon as it sees the swatter will minimize the damage of the swatter. For this reason, it’s more effective to swat flies against a hard surface.

Flies Are Fast Because of Their Halteres

Flies use their halteres, or hindwings, to stabilize their bodies while they’re taking off. The increased stability, according to Royal Society Publishing, allows houseflies to have a faster take-off than other insects.

The increased speed of take-off also contributes to why houseflies are so hard to kill. 

In combination with their broad visual scope, the rapid, stable take-off means that flies can see a swatter or newspaper coming in and take off at an effectively lifesaving trajectory within less than a second.

Smaller Flies Are Harder To Kill

Houseflies aren’t the only kind of flying pest that can infest houses, kitchens, and workplaces. 

There are a variety of flies, or Diptera, by their scientific name, which range in size. They’re typically larger than fruit flies and drain flies but smaller than horseflies or flesh flies, according to the Illinois Department of Public Health.

Houseflies are about ¼” (0.64 cm) long, which is a small target if you’re swinging at it with a swatter or magazine. Larger flies tend to be slower and less agile, which makes them a little easier to kill. Even larger flies have hindwing halteres and compound eyes, however, so swatting them down is still a challenge.

Simple Solutions To Make Fly-Killing Easier

Some flies tend to be more energetic, spending more time in the air, which makes them more difficult to kill. There’s a variety of ways you can get creative with pest control using household materials. 

If these strategies don’t work, it may be time to consult a professional pest control service

Spray Houseflies With Cleaning Solution

Glass cleaners or multi-use cleaners such as Windex or Simple Green (both available on Amazon.com) can be helpful for killing pesky flies. Their cleaning compound will weigh down the housefly, making flight escape impossible. Once the fly is grounded, it becomes much easier to kill.

Treat Common Surfaces With Insecticide

Using sprayable insecticides can make it a lot easier to kill flies, but make sure you’re using indoor bug spray to avoid poisoning yourself in the process. If you can’t locate the fly with the bug spray, put a layer of the poison on windowsills and edges, where flies are likely to land.

Swat Flies From Behind and Below

Houseflies and most other species in the Diptera order, in spite of their compound eyes, do have a blind spot at the back of their heads. If a fly is landed on the ceiling or high on a wall, you may be able to sneak up and swat it without detection by remaining directly behind and below. 

Flies are inherent escape artists, however, so sneaking up on the fly is not the most effective method of ridding your house of the pests .

Use Traps or Insecticide

There’s a wide variety of fly traps that can be used effectively to rid your home of flying pests . Flypaper, honey-pot traps, and bug lights can all be used to lure flies rather than chasing them down with a swatter or bug spray.

If the flies are infested in the house, as can happen when they’re allowed to breed in the walls or unkept nooks and crannies, it may be necessary to fumigate the house.

Final Thoughts

Houseflies aren’t only annoying; they can also be difficult to get rid of. 

Flies, despite being filth carriers with minuscule brains, are extremely quick and agile in the air. This is due to their simple-compound eye system, as well as the presence of hindwing halteres, which allow the housefly to take off fast and steady when the swatter is coming down.

Some easy fly-hunting solutions include using sprayable cleaning solutions, insecticides, and fly traps. If these home methods of pest control aren’t effective, it may become essential to consult a professional exterminator.