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.
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.
“The insects aren't directly flying towards the light but are orienting in such a way that they remain perpendicular to it is giving the illusion of attraction,” added Shockley, who is unaffiliated with the study, via email.
Moths use the light from the moon to help with navigation. This moonlight might be a reason as to why moths are so attracted to artificial lightings such as campfires and light bulbs. As they travel at night they fly towards the moon as it is brighter and will know when they are near the ground as it will get darker.
The time of night and moth's gender also make a difference. There's some suggestion males mistake the heat and scent of candles for females. The Moon's position, phase and visibility also have an effect, and most explanations assume certain moths have evolved to use natural light for orientation by night.
Here's What's Really Happening. Balmy summer nights alive with the sounds of cicadas are so relaxing, until all manner of unruly insects swarm your lights. As much of a nuisance as this may be to us, what's happening to them is far worse.
A candle is irresistible to an insect like a moth which will flock to the flame, and unless pushed away or the flame extinguished, the moth will fly into the tiny fire. The result is frequently fatal. Moths are drawn to flames like we are to temptations and distractions.
Moths are mostly harmless, fluttering insects. Because a moth's mouth parts are so small, it is not physically possible for it to bite a human, with few exceptions, including the “vampire moth." The most that will happen is the moth will leave behind a little dust as it flies away.
Moths are more sensitive to some wavelengths of light -- ultraviolet, for example -- than they are to others. A white light will attract more moths than a yellow light. Yellow is a wavelength moths don't respond to.
Indeed, insects are capable of nociception, so they can detect and respond to injury in some circ*mstances [3]. While observations of insects' unresponsiveness to injury warrant further research, they ultimately cannot rule out insect pain, particularly in other contexts or in response to different noxious stimuli.
Moths are attracted to light, and their behavior of flying near your face may be related to their natural navigational instincts. Moths use a behavior called positive phototaxis, meaning they are drawn towards light sources. This behavior is believed to be an evolutionary adaptation that helps moths navigate at night.
Moths don't fly towards the Moon, either: the idea that moths are trying to navigate by the Moon has been disproved. Exactly why moths fly towards artificial lights still isn't understood – all we know is that artificial lights confuse them in some way.
The phrase “like a moth to a flame” speaks of someone being drawn with intense desire toward something destructive that ultimately delivers no satisfaction, but only the demise of the one drawn to it.
Moths are attracted to a flame which suggests that if you act like a moth, you have an intense and immediate interest. Moths don't seem to have any control about their attraction. The question is, do you have control? Moths appear to be attracted to both heat and light.
The potentially fatal lure of the moth to the flame has long been a scientific mystery. Most nocturnally active moths are attracted to light, a phenomenon known as positive phototaxis. However, some species like the Old Lady (Mormo maura) tend to be repelled by it (they are negatively phototactic).
Explanations of why nocturnal insects fly erratically around fires and lamps have included theories of “lunar navigation” and “escape to the light”. However, without three-dimensional flight data to test them rigorously, the cause for this odd behaviour has remained unsolved.
In summary, of the insects that are attracted to forest fires, one group consisting of platypezid and empidid smoke flies and some cerambycid and buprestid beetles appear to be attracted by smoke while members of the subgenus Melanophila are probably attrated by smoke and heat.
The general explanation is that the moths use a bright, distant light – the moon, say – as a navigation beacon, always flying transversely to it. However, artificial lights are closer than the moon, so the moths gradually spiral in to their doom.
Introduction: My name is Barbera Armstrong, I am a lovely, delightful, cooperative, funny, enchanting, vivacious, tender person who loves writing and wants to share my knowledge and understanding with you.
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