Why Are Moths Drawn to Flames?

iStock/Zffoto
iStock/Zffoto

Around the world, moths make kamikaze dives into light bulbs and open flames with such regularity that they have their own idiom. What is it about lights that make moths so crazy?

For a long time, scientists blamed the moon. Moths used the moon as a navigational beacon, it was argued, keeping it at a constant angle to their direction of travel in order to fly straight. Light sources used by humans, whether they’re campfires or porch lights, threw a monkey wrench into this system. The moon is far enough away that the angle between it and a traveling moth isn’t going to change much, even after the moth flies a great distance. With a closer light source, though, the angle changes considerably after only a short distance. A moth confusing a light bulb or candle flame for the moon, the hypothesis went, would notice this change and attempt to correct its path by turning toward the light. After just a few course corrections, the moth would set itself into a tightening death spiral towards the light and eventually crash into it, either going down in flames or thwacking its poor little head.

On Second Thought...

Over the years, various holes were poked in this hypothesis. For one—and this is a big one—moths might not even use the moon for navigation.

There isn’t much evidence for it, especially when it comes to the over 50 percent of moths that don't migrate and wouldn’t have much use a celestial navigation aid in their short distance travels.

There’s also the fact that moths don't always circle around lights in a closing spiral like the moon hypothesis assumes. Most of the time, they actually head straight for it. Henry Hsiao, a professor of Biomedical Engineering at the University of North Carolina, has tracked moth flights as the bugs headed toward a light source and found that, most of the time, they fly in a straight line toward the light until they get very close, then veer off and circle at a steady distance.

Hsiao’s observations led him to develop a new hypothesis. He’s unsure what causes the moth to make a beeline to a light, but thinks that the circling behavior at close ranges is caused by a visual distortion common to all sighted creatures called a “Mach band.” The band is the region surrounding a bright light that is perceived as being darker than any other part of the sky. Hsiao thinks that moths hang out in the band because they want the cover of darkness for safety, and wind up circling the light until their flight path takes them away from the it (or causes them to crash into it).

Love Hurts

Another explanation, proposed by U.S. Department of Agriculture entomologists in the 1970s, is that the infrared light spectrum emitted by candle flames contains some of the exact same wavelengths of light given off by female moths' luminescent pheromones. In other words, it’s just male moths that are attracted to flames because they wrongly assume that they’re going to get lucky. This doesn’t explain their attraction to UV light, which doesn’t emit the same light wavelengths as moth pheromones, but it does say something very profound about the lure of love.

6 Protective Mask Bundles You Can Get On Sale

pinkomelet/iStock via Getty Images Plus
pinkomelet/iStock via Getty Images Plus

Daily life has changed immeasurably since the onset of COVID-19, and one of the ways people have had to adjust is by wearing protective masks out in public places, including in parks and supermarkets. These are an essential part of fighting the spread of the virus, and there are plenty of options for you depending on what you need, whether your situation calls for disposable masks to run quick errands or the more long-lasting KN95 model if you're going to work. Check out some options you can pick up on sale right now.

1. Cotton Face Masks; $20 for 4

Protective Masks with Patterns.
Triple7Deals

This four-pack of washable cotton face masks comes in tie-dye, kids patterns, and even a series of mustache patterns, so you can do your part to mask germs without also covering your personality.

Buy it: $20 for four (50 percent off)

2. CE- and FDA-Approved KN95 Mask; $50 for 10

A woman putting on a protective mask.
BetaFresh

You’ve likely heard about the N95 face mask and its important role in keeping frontline workers safe. Now, you can get a similar model for yourself. The KN95 has a dual particle layer, which can protect you from 99 percent of particles in the air and those around you from 70 percent of the particles you exhale. Nose clips and ear straps provide security and comfort, giving you some much-needed peace of mind.

Buy it: $50 for 10 (50 percent off)

3. Three-Ply Masks; $13 for 10

Woman wearing a three-ply protective mask.
XtremeTime

These three-ply, non-medical, non-woven face masks provide a moisture-proof layer against your face with strong filtering to keep you and everyone around you safe. The middle layer filters non-oily particles in the air and the outer layer works to block visible objects, like droplets.

Buy it: $13 for 10 (50 percent off)

4. Disposable masks; $44 for 50

A batch of disposable masks.
Odash, Inc.

If the thought of reusing the same mask from one outing to the next makes you feel uneasy, there’s a disposable option that doesn’t compromise quality; in fact, it uses the same three-layered and non-woven protection as other masks to keep you safe from airborne particles. Each mask in this pack of 50 can be worn safely for up to 10 hours. Once you're done, safely dispose of it and start your next outing with a new one.

Buy it: $44 for 50 (41 percent off)

5. Polyester Masks; $22 for 5

Polyester protective masks.
Triple7Deals

These masks are a blend of 95 percent polyester and 5 percent spandex, and they work to block particles from spreading in the air. And because they're easily compressed, they can travel with you in your bag or pocket, whether you're going to work or out to the store.

Buy it: $22 for five (56 percent off)

6. Mask Protector Cases; $15 for 3

Protective mask case.
Triple7Deals

You're going to need to have a stash of masks on hand for the foreseeable future, so it's a good idea to protect the ones you’ve got. This face mask protector case is waterproof and dust-proof to preserve your mask as long as possible.

Buy it: $15 for three (50 percent off)

At Mental Floss, we only write about the products we love and want to share with our readers, so all products are chosen independently by our editors. Mental Floss has affiliate relationships with certain retailers and may receive a percentage of any sale made from the links on this page. Prices and availability are accurate as of the time of publication.

What Do Pets See When They Watch Television?

This dog would like to turn off Netflix's autoplay feature.
This dog would like to turn off Netflix's autoplay feature.
Amatore/iStock via Getty Images

In 2012, a television commercial aired in the UK for Bakers dog food that was conceived and produced specifically to attract the attention of dogs. The spot used high-frequency sounds that are inaudible to human ears. In theory, the dog would be so captivated by the advertisement that owners would take note and perhaps purchase Bakers for their next meal.

This didn’t quite work. Many dogs failed to react at all, proving that when it comes to television ads, humans may be more impressionable than canines.

While pets may not be so easily manipulated, they still find the television screen interesting, sometimes reacting to other dogs, animals, sounds, or images. But what is a dog really seeing when they tune in?

When it comes to color, television is no different from reality for a dog. They have dichromatic vision, which means they see the world through the range of two primary colors, yellow and blue. (Humans have trichromatic vision, able to see the full color spectrum.) Cone cells in canine eyes are also believed to blur their sight to a degree. More importantly, dogs process the frame rate, or “flicker fusion frequency,” of screens differently than people. Humans can detect movement at between 16 and 20 frames per second. Dogs need 70 frames per second or more. If they’re looking at an older television, it might resemble a flip book or even a strobe light effect to them. (Modern sets have a faster frame rate, which is why dogs might be more interested in your high-definition television.)

That helps explain the visuals. What about the content? Typically, dogs will react to the same things that would draw their attention in a room—barking, squeaking toys, or commands. In a study published in Animal Cognition in 2013, nine dogs were observed to see if they could pick out the face of another dog—regardless of breed—on a computer screen instead of another animal or a person. The dogs were rewarded with treats with a successful choice. Though the sample size was small, it indicated dogs can recognize other dogs on a screen. (Which you likely already knew if you’ve ever observed your dog suddenly on alert when a canine appears on camera.)

If your dog used to get excited by another dog on television but has since lost interest, it’s possible they simply became desensitized to their appearance, realizing the image in front of them isn’t going to move out of the boundaries of the monitor.

Content unrelated to dogs might not be of much interest. In a 2017 study published in the International Journal of Human-Computer Studies, dogs presented with three different viewing screens didn’t exhibit any particular preference for one over the other. If they were shown three screens at one time, they seemed uninterested in watching anything at all.

The study also noted that dogs had a limited television attention span. Rather than mimic the binge-watching habits of humans, dogs prefer to glance at a screen for a few seconds at a time. But that behavior could also be breed-specific. Dogs bred for hunting might be interested in moving objects, while dogs that rely more on smell might be indifferent.

And what about cats? In a study published in Applied Animal Behaviour Science in 2008, 125 shelter cats were given a television to view for up to three hours a day. The cats were split into five groups and given a variety of programming to watch, from humans to footage of prey to a blank screen. On average, cats spent just 6.1 percent of the observation time watching the screen. When they did, it was mostly to focus on the prey.

Because cats may react to images of birds and rodents on television, owners should avoid letting them watch unattended. You can also secure the set to a wall to make sure they don’t knock it down.

For the most part, dogs and cats are far more interested in what’s going on in the real world compared to what's on TV. We could probably take a lesson from their limited screen time.