Is the moth fluting the fire, is love or chasing light?

"The mysterious objects are shocked over the pharmaceutical factory, the shape is like a stick, and flying at high speed. This strange phenomenon is the air dragon in the air, or the alternative unknown flying object -flying stick?"

In June 2013, the "Approaching Science" column group aired a program called "Flying Stick Suspected Cloud".

Picture source: CCTV video screenshot

Everyone also guess that the magical "flying stick" is actually just a moth attracted by the camera. Because the camera shutter speed is relatively slow, the moths fly faster. Essence

However, this also seems to confirm the impression of moths again -it is a soft spot for light source. So why are light sources "fatal attraction" to moths?

Is the moth fluttering the fire because the light was mistaken for the moon?

Speaking of flying moths, many people's minds may think of an idiom-moth fluttering fire. The image of moth fluttering fire is reflected in many classics and poems:

For example, in the twenty -seventh time of "Journey to the West", Tang Seng said: "Sweeps the floor and wounds the ants, cherish the moth gauze lamp"; "Snow marks"; even in the eyes of some literati, the moth fluttering became a positive energy symbol of chasing light.

Moth flutter fire (source: blogs.brandeis.edu)

However, in addition to literary and artistic techniques, we also need to know that it is the nature of biology to avoid harm, and fire is undoubtedly dangerous for creatures. Will moths really give up life for the so -called light?

The answer is obviously no.

Although scientists have not fully figured out why the moths are flushed, they have also found many moths to explain the light. The most widely known of which is probably the "moonlight navigation hypothesis".

In the 1930s, German insect scholars von Buddenbrock proposed that as a night -walking animal, moths may rely on moon navigation to determine their orientation when flying at night.

Image source: References 1

This is not difficult to understand, because the moon is very far away from the earth and can be regarded as a very far source of light. When the light is sprinkled on the earth, it can be regarded as parallel light. (As shown in the figure above) flying, you can ensure that you fly forward in a straight line.

But in the face of a light source from the distance, such as candlelight or street lights, this navigation scheme will have certain problems.

Because the distance is very close, the light is transmitted from the light source to the surroundings. At this time, if the moth is flying at a fixed angle, its flight track will be bent to the light source. Finally Either died of fire.

Image source: References 1

Such a wonderful interpretation of mathematical logic has been widely recognized once it was put forward. In order to prove that this hypothesis is indeed reliable, scientists have conducted a series of experiments again.

In 1978, Robin Beck and others at the University of Manchester published a research paper in the journal "Nature". In this study, they recorded the moth's flight trajectory through a subtle design.

In the research design, when the moon was not blocked, the moth could indeed fly along the straight line, but when the moon was covered, or the moth's eyes were covered, they could not fly the straight line.

After further exploring the impact of lights on the moth, they found that when the lights exist, the moth changes the flight trajectory according to the location of the light. Not only that, the height and size of the light source also have an important impact on the moths. When the height of the light source is high, it is easy to attract moths far away.

It is not difficult to see the impact of light sources on moths on the moths from the experiments above, but the reason behind the moth fluttering is because they regard the lights as the moon in the academic circles. At least, some scientists think that the moths may flutter the fire. It is because of love.

Love chasing is better than love partners?

Fabur recorded such an interesting phenomenon in his book "The Insect": If the female moth and candlelight in the same room are placed in the same room, most male moths will ignore the female existence and still fly towards the candlelight. Staged a story of a moth fluttering.

You know, the top priority in the life of male moths is to mate with females, leaving their own descendants. Why do male moths make such a choice between light sources and sex hormones?

Source of moths that are mating: inaturyist.org

If the ultimate goal of the male moth rushing on the moonlight is to find the female to mate. When the female is in front of her eyes, it is really difficult to explain the "moonlight navigation hypothesis".

In this regard, some scientists believe that in the eyes of male moths, the light source may be regarded as a female moth, and the temptation of this female moth to the male moth is greater.

This is not impossible. In the 1970s, Philip Caraham proposed the "infrared hypothesis" of the attractiveness of moths.

His view is that the sex hormones of female moths will be affected by ultraviolet rays into the excitation state in the air, emitting infrared light, which will be received by male moths. The intensity of infrared light is greater. For male moths, like a super female moth, of course, it will rush to it.

Although this hypothesis cannot perfectly explain the phenomenon of moths fluttering, after all, female moths will approach the lights, but they cannot completely rule out that there is no possibility. In the moths, there are indeed many species that have the gender differences in light. For example, when the lights seduce dance poisoning moths, scientists find that the number of male moths attracted to the lights is far more than females. This phenomenon is found in many moth species.

Image source: References 3

It is worth mentioning that whether the moth flutter the fire because of the fault of the navigation system or because of the "fantasy female" attracted, their light -oriented behavior is not to find death, but because human invention affects the evolution of moths in evolution A kind of instinct formed in the process.

However, with the passage of time, the power of evolution seems to be quietly changing this.

Evolutionary behavior under light pollution

Let's think about another problem. If the effect of artificial light source on moths can cause the evolution of moths, the moths in the city and most of the time living in the dark sky, moths from the countryside when they face the artificial light source Is it different?

I believe everyone will give a positive answer.

With the same question, the two biologists conducted a study to discuss the possible impact of modern artificial lighting on the evolution of moths. This research was published in the journal "Biology Express" in 2016.

In this study, scientists tested the flight behavior of 1048 mink moths under the light. They collected moths from different regions. Among these larvae, 320 were from rural areas, and 728 were captured from light pollution areas. These larvae are raised in the laboratory, with 16 hours of light and 8 hours of darkness per day until the feathering into adults.

Mink Moth Picture Source: References 4

Two to three days after the feathers, they were placed in a flying cage with fluorescent tube on one side to observe their flight behavior under the light source. The results show that the attractiveness of light sources to moths from light pollution areas is significantly lower than moths from rural areas.

Overall, moths from light pollution areas are reduced by 30%from moths from rural areas from rural areas, which seems to indicate that the species has evolved under light pollution, as predictive -far away from artificial light.

You can understand this way, just like a food, you love to eat anymore, you don't want to eat too much. Similar Sensitive.

Researchers believe that this change should increase the reproduction rate of moths in these cities. After all, from the previous research, we can conclude that the attractiveness of light sources to moths has decreased, and the attention of the moth to the other half is relative. Well, it has risen.

However, the researchers also believe that this success is also costly. In order to avoid lights, moths may reduce flight, so they will not pollinate so many flowers, and spiders and bats may not get enough moths to come to come. As food.

However, as long as it is not to die, what does this have to do with the moth?

Produced: Popular Science China

Author: EVEE (School of Life Sciences, Peking University)

Producer: China Science Popularization Expo

Edit: Wang Tingting

references:

Mohamed, A. A. A., Mohamed, Y. S., El-Gaafary, A. A., & Hemeida, A. M. (2017). OptImal Power Flow user moths algorithm. Electric Power Systems Research, 142, 190-206.

Baker, R. R., & Sadovy, Y. (1978). The distance and nature of the light-trap response of moths. Nature, 276 (5690), 818-821.

Cheng Wenjie Zheng Xialin, Wang Pan, Lei Chaoliang, Wang Xiaoping. (2011). The gender differences and influencing factors of insect light [J]. Application of ecological Journal. 22 (12), 3351-3357.

Altermatt, F., & Ebert, D. (2016). Reduced Flight-Light Behavior of Moth Popurations Exposed to Long-Term Urban Light POLLUTION.

The China Science Popularization Expo is the Science Popular Science Platform of the Chinese Academy of Sciences. It is sponsored by the Computer Network Information Center of the Chinese Academy of Sciences. Relying on the high -end scientific resources of the Chinese Academy of Sciences, it is committed to spreading cutting -edge scientific knowledge and providing fun science and education services.

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