Views: 1 Author: Site Editor Publish Time: 2022-04-20 Origin: Site
How long has it been since you saw a firefly with a small lantern?
Thinking about it seriously, it seems that the natural scene with a little fluorescent light in the dark night is getting farther and farther away from us，many people have never even seen fireflies in person - and indeed, fireflies are becoming rarer and rarer.
In fact, fireflies face the same predicament as most creatures - habitat loss has severely affected their survival. But what you might not know is that nighttime light pollution is the second-biggest threat to firefly populations worldwide.
Light pollution silences fireflies
In academia, night lighting light pollution has its own name, called ALAN (Artificial Light At Night). With the continuous development of the economy and the brighter lights, ALAN has become one of the ecological problems faced by the world. It is conservatively estimated that 23% of the land is subject to varying degrees of nighttime lighting pollution. Before humans light up the night sky with lights, only celestial bodies such as the moon and stars and luminous creatures such as fireflies can decorate the darkness.
Today's convenient lights light up our lives, but we didn't expect the brighter and brighter lights to bring disaster to fireflies. 49 firefly researchers from different countries conducted a comprehensive assessment of firefly populations in various regions of the world. It is believed that the light pollution caused by excessive night lighting makes the survival of fireflies precarious.
The direct effect of nighttime light on fireflies is to reduce their frequency of activity. A field comparison experiment confirmed this conclusion—a study in the Brazilian countryside found that the occurrence of fireflies was significantly reduced after light exposure. Even with the weakest direct light (equivalent to a full moon, about 0.0438 lux), the local fireflies of the genus Photinus were only half as active as they were without light. And through parallel experiments by adjusting the light intensity, it was found that as the light intensity increased, the fireflies became more and more "shy", In the strongest light group, fireflies were less than 10% active after being affected by light.
Even if they're not too shy to go out because of the light, fireflies that are active at night have a hard time, because the light can also affect their courtship behavior. After sunset, when male fireflies start courting, the specific flash frequency we see is actually their romantic language of affection. The luminous frequency of each species is different, but they are all unique love words in the eyes of the opposite sex of the same species.
Unfortunately, light pollution makes the expression of firefly love words no longer accurate. After being affected by light, the male's flash parameters will change, such as frequency and intensity. At this point, in the eyes of females, these love words become unfamiliar and incomprehensible words!
In addition, the light "persecution" of fireflies is not gender-selective, and in addition to males, females are also affected. After the male firefly sends out the flash signal of love, if the female is in love with the other, it will send out a flash of a specific frequency in response to the love, indicating acceptance of courtship. Light pollution also changes the frequency of flashes in females.
Taking the firefly Photinus obscurellus as an example, the normal female response flash should consist of 5 patterns,but under the strong red light, the female can only emit a single, solitary flash. At this time, the language of love fails in both directions, and male and female can no longer understand each other's love words. This unique and beautiful way of courtship has lost the effect it should have had for thousands of years, and the likely result is a dead end that cannot continue to reproduce.
