A Firefly's Twinkle Doubles as a Warning Sign to Predators

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iStock

A group of fireflies twinkling on a summer's night may look peaceful, but those flashing lights can send an unsettling message: 'If you eat me, you'll regret it.' That's what a team of researchers discovered when conducting a study published in Science Advances.

According to the new research, reported by ScienceNews, a firefly's flashing behind acts as a warning signal to predators like big brown bats. Entomologists have long known that fireflies use their lights to attract mates, but the suspicion that they also use them to avoid becoming dinner wasn't confirmed until recently.

To investigate this theory, a team of scientists from Boise State University and other institutions exposed fireflies to three bats with no experience hunting the insects. Fireflies contain toxic chemicals that make them unappealing to predators. After tasting a few of the bugs and spitting them out, the bats learned to stop going after them altogether.

To see what part light played in these interactions, the researcher conducted a separate experiment. They attached tiny paper belts to each firefly and painted them with two coats of black paint—a process that took about 45 minutes for each specimen. The result was a cloak that effectively hid the fireflies' light show. When bats were set loose on the snuffed-out group, it took the predators about twice the amount of time to realize the fireflies were toxic and ignore them. With no visual warning signs to tip the bats off, the study authors suspect that the bats eventually learned to identify the insects from their flight patterns via echolocation.

Fireflies don't light up only when they see a bat swooping their way: Males each have their own "flash fingerprints" they use to attract mates, and females blink in response when they see a display they like. The new study suggests that predators' reaction to this bioluminescent adaptation may have influenced its evolution.

[h/t ScienceNews]

How to Relieve a Tension Headache in 10 Seconds, According to a Physical Therapist

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iStock.com/SIphotography

The source of a pounding headache isn't always straightforward. Sometimes over-the-counter painkillers have no effect, and in other cases all you need is a glass of water to ease the pain. When it comes to a specific type of a headache, Prevention recommends a treatment that takes about 10 seconds—no fancy medications or equipment required.

If you're experiencing pain throughout your head and neck, you may have a tension headache. This type of headache can happen when you tense the muscles in your jaw—something many people do when stressed. This tightening triggers a chain reaction where the surrounding muscles in the head and neck become tense, which results in a painful, stiff feeling.

Fortunately, there's a way to treat tension headaches that's even easier than popping an Advil. David Reavy, a physical therapist known for his work with NFL and NBA athletes, recently suggested a solution to Prevention writer Christine Mattheis called the masseter release. To practice it yourself, look for the masseter muscle—the thick tissue that connects your jawbone to your cheekbone on either side of your face—with your fingers. Once you've found them, press the spots gently, open your mouth as wide as you can, close it, and repeat until you feel the muscle relax. Doing this a few times a day helps combat whatever tension is caused by clenching your jaw.

If that doesn't work, it's possible that the masseter muscle isn't the source of your headache after all. In that case, read up on the differences among popular pain killers to determine which one is the best match for your pain.

[h/t Prevention]

Why Do Hangovers Get Worse As You Get Older?

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iStock/OcusFocus

“I just can’t drink like I used to” is a common refrain among people pushing 30 and beyond. This is roughly the age when it starts getting harder to bounce back from a night of partying, and unfortunately, it keeps getting harder from there on out.

Even if you were the keg flip king or queen in college, consuming the same amount of beer at 29 that you consumed at 21 will likely have you guzzling Gatorade in bed the next day. It’s true that hangovers tend to worsen with age, and it’s not just because you have a lower alcohol tolerance from going out less. Age affects your body in various ways, and the way you process alcohol is one of them.

Because your body interprets alcohol as poison, your liver steps in to convert it into different chemicals that are easier to break down and eliminate from your body. As you get older, though, your liver produces less of the enzymes and antioxidants that help metabolize alcohol, according to a study from South Korea. One of these enzymes—called alcohol dehydrogenase (ADH)— has been called the “primary defense” against alcohol. It kicks off the multi-step process of alcohol metabolization by turning the beer or booze—or whatever you imbibed—into a chemical compound called acetaldehyde. Ironically, this substance is even more toxic than your tipple of choice, and a build-up of acetaldehyde can cause nausea, palpitations, and face flushing. It usually isn’t left in this state for long, though.

Another enzyme called aldehyde dehydrogenase (ALDH) helps convert the bad toxin into a new substance called acetate, which is a little like vinegar. Lastly, it’s converted into carbon dioxide or water and expelled from your body. You’ve probably heard the one-drink-per-hour recommendation, which is roughly how long it takes for your liver to complete this whole process.

So what does this mean for occasional drinkers whose mid-20s have come and gone? To summarize: As your liver enzymes diminish with age, your body becomes less efficient at metabolizing alcohol. The alcohol lingers longer in your body, leading to prolonged hangover symptoms like headaches and nausea.

This phenomenon can also partly be explained by the fact that our bodies tend to lose muscle and water over time. People with more body fat don’t break down alcohol as well, and less water in your body means that the booze stays concentrated in your system longer, The Cut reports. This is one of the reasons why women, who tend to have a higher body fat percentage than men, often suffer worse hangovers than their male counterparts. (Additionally, women have fewer ADH enzymes.)

More depressingly, as you get older, your immune system deteriorates through a process called immunosenescence. This means that recovering from anything—hangovers included—is more challenging with age. "When we get older, our whole recovery process for everything we do is harder, longer, and slower," gastroenterologist Mark Welton told Men’s Health.

This may seem like a buzzkill, but we're not telling you to put down the pint. However, if you're going to drink, just be aware of your body’s limitations. Shots of cotton candy-flavored vodka were a bad idea in college, and they’re an especially bad idea now. Trust us.

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