Flies are attracted to TV screens for a few different reasons. The flickering light, heat, and electromagnetic radiation emitted by TV screens are all factors that attract flies.
Flickering Light
The flickering illumination of TV screens attracts flies. Older CRT TVs flickered at a high frequency as the electron beam scanned across the screen to create images. Newer flat-screen TVs flicker at a slower refresh rate. While this flickering is imperceptible to human eyes, flies can see it and are drawn to it.
Flies have compound eyes with thousands of ommatidia, which are the individual visual receptors. This gives them a high flicker fusion rate, meaning they see flickering light as constant illumination rather than flickering on and off. The flickering light of TV screens mimics a fly’s natural environment and the flickering makes them think they have found a potential food source, habitat, or mating location.
Heat Emission
TV screens emit heat as a byproduct of their function. The cathode ray tube of old CRT TVs gave off a significant amount of heat. While newer flat-screen TVs run cooler, they still produce noticeable warmth.
Flies gravitate toward heat sources for a couple reasons. The warmth from TV screens is similar to the heat of decaying organic material that flies feed on. The heat also raises the temperature, creating uplift air currents that flies can soar and glide on with minimal effort. Seeking out heat allows flies to more easily search for food, shelter, and mates while expending less energy.
Electromagnetic Radiation
The electromagnetic radiation given off by TV screens attracts flies. This includes forms of non-ionizing radiation like infrared, visible light, and radio waves. TV screens give off varying amounts of radiation depending on the type of display technology.
Research indicates that flies can detect electromagnetic fields through special sensory receptor cells. These receptors allow flies to perceive and navigate by the Earth’s natural electromagnetic field. The electromagnetic radiation from TVs provides flies with stimuli similar to what they use for orientation and movement in their environment.
Details on Fly Vision
To better understand why the visual flicker, heat, and electromagnetic radiation of TV screens appeal to flies, it helps to take a closer look at fly vision and sensory capabilities:
- Flies have compound eyes with thousands of ommatidia (individual facets). House flies have around 4,000 ommatidia in each compound eye, while horse flies have up to 28,000.
- The many ommatidia give flies an extremely wide field of view and ability to detect quick movements.
- Each ommatidium has a lens that focuses light onto visual receptor cells. The receptor cells transmit visual signals to the optic lobes of the fly’s brain.
- Flies can see colors, including green, blue, and ultraviolet. Their eyes contain photoreceptors sensitive to a broad spectrum of wavelengths.
- Flies view the world in mosaic-like fragments rather than distinct images. But their compound eyes allow superb motion detection.
- Flies have a high flicker fusion rate of 200-300 Hz. This means they see flickering light as constant illumination up to 300 flickers per second.
In addition to vision, flies have specialized sensory organs that detect heat, humidity, scents, tastes, and electromagnetic fields. Their senses combine to make flies adept at locating sources of food, breeding sites, and thermal updrafts for flight. TV screens happen to emit visual, thermal, electromagnetic, and even olfactory stimuli that flies are naturally attracted to.
Other Factors That Attract Flies
While the light, heat, and radiation of TV screens are the main factors that attract flies, there are some secondary reasons as well:
- Scent: TVs give off faint scents from their inner components and electronics that flies can detect.
- Motion: The moving images and flashing lights of TV screens resemble small flying insects that flies hunt.
- Reflections: Flies are drawn to the reflective glass or plastic screens of modern TVs.
- Humidity: The warmth from TVs causes evaporation that creates a slight increase in humidity around the screen.
- Static: Static electrical charge can build up on TV screens, and flies feel attracted to areas of high static.
While less significant than light, heat, and radiation, these other factors add to the appeal of TV screens in the sensory world of flies.
Do Flies Mistake TV Screens for Open Air or Water?
A common assumption is that flies are so dumb they mistake TV screens for open air or bodies of water. While flies do sometimes behave this way around screens, it’s not because they’re fooled into thinking the TV is a physical opening or pond.
Rather, flies are attracted by the light and motion cues that resemble their natural environment. A TV screen can mimic the type of stimuli a fly would see near a fresh food source, breeding ground, or migration path. The flies are not confused about the physical makeup of the screen itself—they instinctively respond to the sensory signals the TV emits.
Fly Groups Most Attracted to TVs
While all flies are drawn to TV screens to some extent, these types are especially likely to hang around them:
- House flies – abundant around human dwellings
- Fruit flies – gather around ripe fruit and fermented foods
- Blow flies – breed in dead animals, feces
- Bottle flies – associated with decaying organic material
- Flesh flies – feed on decaying matter as larvae
- Stable flies – bite mammals to extract blood
- Horse flies – painful bites, attraction to motion and heat
- March flies – found near wetlands, drawn to heat and light waves
Species like house flies and fruit flies commonly live around people, putting them in proximity to TVs. Blow flies, bottle flies, and flesh flies flock to the heat and light waves. And aggressive biters like horse flies and stable flies zero in on the flickering movement and carbon dioxide from humans watching TV.
Do TV Screens Attract More Flies Than Lights?
TV screens seem to attract more flies than typical indoor lights. There are a few reasons for this:
- TVs emit infrared radiation that is invisible to humans but detectable by flies.
- The flickering and flashing illumination of TVs mimics flies’ natural environment more than steady indoor lighting.
- TVs produce visual stimuli, heat, and electromagnetic variance not found with most indoor lights.
- Human activity around TVs produces smells, warmth, humidity, and carbon dioxide plumes that appeal to flies.
However, extremely bright lights that produce considerable heat and UV radiation can attract flies in densities comparable to TV screens. Black lights and certain types of security lights are examples. But overall, the combination of visuals, heat, and electromagnetic variance makes TV screens more appealing to flies than most typical indoor light sources.
Do Flies Have a Preferred TV Display Type?
Over the years as TV technology has evolved, some display types seem to attract more flies than others:
- CRT (cathode ray tube): The most attractive to flies due to high heat emission, intense flickering, and strong electromagnetic fields.
- Plasma: Releases noticeable heat and uses phosphor excitation with UV emissions to create images.
- LCD (liquid crystal display): Emits less heat but still has flickering backlight and plenty of light waves to attract flies.
- OLED (organic light-emitting diode): Produces vivid display with pure blacks but minimal heat, so somewhat less fly attraction.
- DLP (digital light processing): Uses spinning mirrors and doesn’t heat up, so not as appealing to flies.
The bottom line is that any type of TV technology involves flickering visible light wavelengths along with some heat and electromagnetic radiation—all of which attract flies. But CRT TVs seem to draw the most flies based on their intense heat, light pulses, and electromagnetic fields.
Do TV Screens Attract More Flies Than Computer Monitors?
TV screens seem to attract more flies than computer monitors in most cases. There are a few factors that can explain this:
- TV screens are larger, giving off more total heat, light, and electromagnetic radiation.
- TVs often have brighter display settings than monitors, along with more flashing images.
- Regular TV viewing involves people sitting still on a couch, creating plumes of carbon dioxide and body heat.
- TVs are more frequently located in living spaces, while monitors tend to be in offices.
However, very large and powerful gaming monitors with intense brightness settings can attract flies reasonably well. And desktop computer monitors with CRT displays generate plenty of heat and flicker. But on the whole, the size and typical viewing conditions of TV screens make them more effective at attracting flies than traditional computer monitors.
Do New TVs Attract Fewer Flies & Work Better for Repelling Them?
The transition from CRT displays to flat-panel display technologies like plasma, LCD, and OLED has resulted in TVs that run cooler and flicker less noticeably. The reduced heat emission and more stable illumination make newer TV types slightly less attractive to flies overall.
However, even the latest flat-panel TVs still give off heat and flickering light wavelengths that appeal to flies. So while advances in efficiency and display quality may have reduced the fly attraction effect, flies are still drawn to modern TV screens.
That said, some features of newer TV displays can help repel flies:
- Brighter screens make it harder for flies to see what’s on the display due to glare.
- Faster refresh rates around 120 Hz reduce visible flicker to flies.
- Darker black levels and contrast of OLED and QLED TVs give flies less light stimuli.
- Matte and anti-reflective screen finishes diffuses unfavorable light waves.
So while the fundamental technologies still attract flies, characteristics of the latest premium TVs may slightly aid in repelling them.
Do TVs Attract More Flies at Night?
TV screens tend to attract more flies during nighttime viewing than daytime:
- At night, ambient light is lower, so the illumination of the TV screen is more prominent.
- Flies are naturally more active at dawn and dusk when there are fewer predators.
- With blinds closed at night, the indoor heat and humidity rise which flies favor.
- CO2 and scents linger more at night due to less air circulation.
The darker conditions make the flickering TV screen stand out more to flies at night. And since flies increase activity during low light periods, nighttime TV viewing puts humans in closer proximity to flies searching for visual stimuli in the darker environment.
Do TVs Attract More Flies Than Phones/Tablets?
TV screens attract considerably more flies than the screens of smartphones, tablets, and laptops. This comes down to a few key variables:
| TV Screens | Phones/Tablets | |
|---|---|---|
| Screen Size | Large, 50″ or more | Small, around 5-15″ |
| Light Emission | High intensity | Low intensity |
| Heat Emission | Noticeable warmth | Minimal heat |
| Viewing Position | Far away, sedentary | Close up, brief |
The much larger size of TV screens results in greater light, heat, and electromagnetic outputs. And people tend to watch TV from a distance for longer periods. This combination offers flies more desirable sensory stimuli than the smaller, cooler screens of portable devices that humans view briefly from a close range.
Do TVs Attract Certain Flies More Than Others?
While all flies are attracted to TV screens, certain species seem especially draw to them:
- House flies – abundant in homes, attracted to light and heat
- Fruit flies – source food via scent, swarm ripe fruit
- Blow flies – follows scents to lay eggs on meat, feces
- Flesh flies – feeds on fluids from decaying matter
- Stable flies – bites mammals, notices flickering light
- Bottle flies – prefers warmth, decay smells
- Horse flies – hunts large mammals, likes heat
- Crane flies – drawn to lights at night due to phototaxis
These flies have evolutionary traits and lifestyle behaviors that make TV viewing environments especially attractive to them. The combination of human presence, artificial light, and simulated natural stimuli lures them in.
How Far Away Can Flies Detect Light/Heat from TVs?
Experiments suggest flies can detect light and heat from TV screens at these approximate distances:
- Light sensing – up to 30-40 feet away
- Heat sensing – around 10-15 feet away
- Strong, stark light contrast – up to 60 feet away
- Rapid light flickering – approx. 20 feet away
Within around 15 feet, flies can distinctly sense the heat signature of a TV screen. The light waves are detectable at greater distances depending on variables like the size of the TV and contrast ratio. Overall, flies can perceive TV screens using vision and thermoreception from impressively far compared to humans.
Do Newer LED & OLED TVs Deter Flies?
Some key advantages of newer LED and OLED TVs in regards to deterring flies:
- LED TVs last longer and degrade more slowly than LCD displays.
- OLED TVs have pure black levels, emitting no light for dark images.
- Both LED and OLED TVs use less energy and run cooler than older displays.
- They have very fast response times that reduce visible flicker.
- High contrast and bright screens create glare that flies avoid.
While LED and OLED TVs still produce light spectrums that attract flies, their advances in efficiency, response time, contrast ratio, and heat reduction provide subtle benefits for repelling flies compared to older display technologies.
Conclusion
Flies gravitate toward TV screens because of their flickering illumination, heat emission, and electromagnetic radiation. These stimuli mimic the natural sensory cues that flies use to locate food, breeding sites, and warm air currents. Species adapted to living around humans and detecting light, warmth, and motion are most strongly attracted to TVs. And characteristics of certain display technologies like CRT and plasma make them even more appealing to flies.
Recent LED, OLED, and other displays have reduced heat and flickering which slightly deters flies. But even new TV models still emit the types of visual, thermal, and electromagnetic energy that appeals to flies’ sensory abilities and behaviors. So while TV technology continues to advance, flies will likely remain drawn to our television screens when we’re enjoying our favorite shows.