"Crossing the river by feeling one's way across", he is the first person in China to study and protect fireflies

The scene of chasing fireflies on summer nights is a childhood memory for many people. However, how fireflies, which illuminate the night sky like elves, glow and how to control the glow have always been unsolved mysteries in the scientific community.

On March 6, a paper published in Nature Communications revealed the secret of firefly luminescence. The first author of the paper is Fu Xinhua, a professor at the College of Plant Science and Technology of Huazhong Agricultural University. He is the first doctor in China to engage in firefly research and has discovered and named many types of fireflies, including Firefly lei, Firefly wuhan, Firefly qiongyu, etc.

Pained by the sharp decline in the number of fireflies, Fu Xinhua actively devoted himself to the cause of firefly protection. Through lectures, book writing, photography and other forms, he conveyed to the public the concept of scientific firefly viewing and protection of firefly habitats. He also established the firefly environmental protection organization "Hubei Firefly Research Center" and is known as the first person in China to study and protect fireflies.

Become a Firefly Hunter

Fu Xinhua was curious about fireflies when he was a child. He said that his curiosity was partly due to the nature of children and partly due to his parents' different opinions on the origin of fireflies. How did fireflies come from? Because of the allusion of "rotten grass turning into fireflies", his father said casually: "They turned from cow dung." But his mother said: "Fireflies are the souls of the dead, holding lanterns to look for their relatives in the world, wishing them good luck and health." His mother's comment made Fu Xinhua have a little more awe for fireflies.

After the sun sets, fireflies glow and dance near a stream (Photo by Fu Xinhua)

Born in Qingdao and raised in a naval compound, Fu Xinhua graduated from Shandong Agricultural University with a bachelor's degree in botany in 2000 and was admitted to Huazhong Agricultural University as a graduate student in entomology. On a sultry summer night, he found a light spot in the weeds on the roadside, which made him curious about the glowing elves as a child. It was a firefly larva. The huge spherical light organ and the long flashing light amazed Fu Xinhua, and he fell into the "pit" of firefly research.

Why do fireflies glow? What is the use of glowing? These questions lingered in Fu Xinhua's mind. He applied to his supervisor for permission to study fireflies, but at that time, there was no relevant research in China, and there was almost no literature. Fu Xinhua was faced with a blank slate. People around him were puzzled, and many teachers and classmates told him: "There is no future in studying fireflies, and you can't apply for scientific research funds..." Even his father asked him worriedly: "What is the point of studying fireflies?" Fu Xinhua ignored them and plunged into his interest.

Facing the challenges

Running along the lakeside grass and through the bushes, Fu Xinhua chased those glowing insects. The fireflies he collected were brought back to the laboratory and became his treasures.

"To study fireflies, it is best to raise them well first." After more than ten years of hard work, Fu Xinhua has established an efficient "aquatic firefly factory breeding technology system" and "firefly staggered breeding technology system." This not only laid the foundation for his subsequent scientific research, but also solved the problem of firefly protection and landscape restoration.

In addition to scientific research, Fu Xinhua is keen on popular science and has written more than ten popular science books. His work has been recognized by everyone, but Fu Xinhua feels that it is not enough. The development mechanism of the firefly adult light organ and the flash control mechanism are the two most basic and difficult problems in firefly research. He is determined to pick these two "crown jewels".

Fu Xinhua conducting field research at night

"Perhaps if we conduct research at the genetic level, we will have the hope of solving scientific problems in essence." With the development of biotechnology, Fu Xinhua tried to sequence the whole genome of fireflies in 2015. In 2017, the deeply sequenced and assembled firefly genome was released. However, what puzzled Fu Xinhua was that through comparative research, no new genes directly related to the development and flash control of the firefly adult light organ were found. The research was stuck.

Misfortunes never come singly. During a field survey, Fu Xinhua almost lost his life. While investigating the characteristics of firefly habitats in the dense forest, he slipped and fell into a deep pool. In extreme hypoxia, he struggled to the surface to seek help and was fortunately rescued.

Watching Fireflies

The turning point came in 2018. "Did a common gene evolve the function of luminescence? Can we hit the target faster by starting with genes related to abdominal development?" Fu Xinhua suddenly had this idea.

After sequencing the transcriptome of the early, middle, late stages and adults of the aquatic firefly, Lupinus raderii, Fu Xinhua locked on the Homeobox transcription factor. This is a type of developmental regulatory gene that controls the development of animal body shape and contains nearly a hundred genes. He then led the team to conduct interference experiments on these genes one by one. The experiment found that two key transcription factors, "AlAbd-B" and "AlUnc-4", interacted to activate and regulate the expression of luciferase, a luminescent protein. Silencing any of these transcription factors will cause the firefly to not glow or even "melt".

At the same time, Fu Xinhua also figured out the working mechanism of these two transcription factors. From a cellular level, fireflies glow because "luciferase" plays a role in the organelle "peroxisome". Luciferase is often expressed in large quantities in the cytoplasm, and in order for luciferase to enter the peroxisome, it is inseparable from the peroxisome's transmembrane transporter. "These two transcription factors also regulate the peroxisome's transmembrane transporter, thereby transporting luciferase in the cytoplasm into the peroxisome." Fu Xinhua introduced.

The "Milky Way" formed by fireflies flows above the grass (Photo by Fu Xinhua)

Doing basic research is like sitting on a "cold bench". In his 24 years of firefly research, Fu Xinhua has built a "bench" and then heated it up. Fireflies are often seen as worthless scientific research, but Fu Xinhua doesn't think so: "In fact, there is a lot of room for research on fireflies. Foreign scientists have conducted bionic research based on the characteristics of firefly light sources to further improve the luminous efficiency of LEDs. There are also applications of fireflies in the fields of medicine, mining, navigation, and other fields, and extended to cutting-edge directions such as space exploration and cancer treatment."

Even if he really gets nothing, Fu Xinhua will not lose the motivation to keep pursuing. Back then, when he felt helpless, he wrote a letter to Nobuyoshi Ohba, a Japanese scholar and the world's authority on firefly research, about his confusion. Unexpectedly, the old man came to China in person, found Fu Xinhua and told him that no scientist engaged in basic research was sure that their research was valuable. Many scientists have spent their entire lives without any gains, but all human civilization and achievements come from people who bravely explore the unknown world. "I think I can never explore the mystery of fireflies in my lifetime. Next, I will pick the second 'gem' - revealing the mechanism of firefly flash control." Fu Xinhua has his own rhythm for what to do in the future.