Junior Principal Investigator
Institute of Infectious Diseases
After heavy rainfalls, mosquitoes run rampant. Diseases like dengue fever, Japanese encephalitis, malaria, yellow fever, and filariasis fall under their "jurisdiction". Vector-borne diseases caused by mosquitoes, flies, cockroaches, fleas, ticks, mites, lice, midges, and blackflies are significant threats. According to the World Health Organization, over 200 million people globally contract malaria from mosquito bites each year, with approximately 725,000 fatalities. In China, mosquito-borne diseases account for 5%-10% of all infectious disease cases annually, and 30%-40% of all infectious disease-related deaths.
"Do you know how many species of mosquitoes exist in the world?" Feng Liu asked, his previously shy demeanor lighting up with excitement. "There are more than three thousand!"
"When I was a child, I had the chance to raise silkworms. I would collect mulberry leaves for them and observe their lifecycle—from larva feeding to cocoon formation, adult mating, egg-laying, and hatching into baby larvae, starting the cycle anew. At the time, I didn't realize that these life phenomena were controlled by their hormones and nervous systems."
Feng Liu, just turned to 36 this year, has dedicated 19 years to the field of entomology.
In 2004, Feng Liu entered Shenyang Agricultural University and chose Entomology without hesitation. "I didn't think much about it back then, I just liked it," Feng Liu said with a smile.
In 2008, Feng Liu began his graduate studies in entomology at the Chinese Academy of Agricultural Sciences. "Having a good mentor is crucial during one's studies. My graduate advisor, Dr. Wu Qingjun, is a diligent and meticulous scholar. Being influenced by her passion for scientific work, I genuinely wished to become someone like her." In 2011, Feng Liu received an offer from Nannan Liu 's lab at Auburn University, and thus, his journey towards a Ph.D. in the United States began.
01 The Pioneer of Bed Bug Research
In many old houses in the United States, bed bugs, infamous for feeding on human blood, are a common nuisance. Early in his career, Feng Liu's mentor, Professor Liu, encouraged him to investigate bed bugs to uncover the neural mechanisms driving their feeding behavior. During his research, Feng Liu noticed that the tungsten wire electrodes used for detecting neural activity frequently malfunctioned, hindering his progress. Determined to resolve the issue, he meticulously examined each step of the detection process and discovered that the salt used for etching the tungsten was interfering with the recordings. By ensuring the electrodes were thoroughly cleaned of salt before use, he resolved the issue and made significant strides in his work. "The strong and resilient women in my life—from my mother to Professors Qingjun Wu and Nannan Liu—have deeply influenced me. Their perseverance has instilled in me a commitment to hard work and diligence," he remarked. Often working late into the night, Feng Liu diligently recorded the neural and olfactory receptor activities of bed bugs over five years, uncovering their attraction to certain human odors at the cellular and molecular levels.
Feng Liu's research revealed that bed bugs display heightened neural activity in response to carbon dioxide and certain warm-blooded animal odors, providing insights into their blood-feeding behavior and paving the way for new attractants and repellents. "Our work in the bed bug field is truly cutting-edge in both depth and scope," he stated proudly. In recognition of his remarkable achievements during his doctoral studies, Feng Liu was awarded first prize in the student competition by the Overseas Chinese Entomologists Association in 2014 and was named one of the top ten outstanding Ph.D. graduates at Auburn University in 2016.
02 The Mosquito Hunter
In ancient times, people burned dried wild chrysanthemums to repel mosquitoes. Today, modern companies extract compounds from chrysanthemum plants for the same purpose. In 2016, Feng Liu began his postdoctoral research in Professor Ke Dong's lab at Michigan State University. Professor Dong suggested he investigate how mosquitoes sense repellents by identifying the receptors in their nerve cells that detect "pyrethroids." This meticulous task involved examining thousands of olfactory sensilla in mosquito antennae, requiring immense patience. Feng Liu dedicated himself to the lab, carefully monitoring neural signals on the screen each day. "You might see me sitting there motionless and think I am bored, but the microscopic world is ever-changing and full of potential," Feng Liu explained. "The person who has a strong mentality of pursuing fame and fortune and urgently wants an answer may not be suitable for scientific research. Follow your curiosity, always seek knowledge and stay focused—this is the essence of true scientific researchers."
Two years later, Feng Liu and his team identified the specific nerve cells and olfactory receptors in mosquitoes that respond to chrysanthemum extracts. They took their research further by pinpointing the key components in these compounds and exploring alternatives to enhance mosquito repellent products. "Mosquito-borne viruses cause significant deaths, especially in Africa and Southeast Asia. I hope my work can help protect people from mosquito-borne diseases," Feng Liu said. The team soon discovered that a compound called beta-caryophyllene had strong activity against the mosquito receptors for chrysanthemum extracts. They demonstrated that this activity was lost in genetically modified mosquitoes lacking these receptors, which nullified beta-caryophyllene's repellent effect. This breakthrough was ultimately published in Nature Communications.
03 Mosquitoes "Going Vegetarian"
Professor Laurence Zwiebel at Vanderbilt University is a leading expert in mosquito-borne diseases. During his postdoctoral research, Feng Liu often read Zwiebel's work and long admired his expertise. In 2018, Feng Liu received an offer to join Zwiebel's lab at Vanderbilt University for his second postdoctoral stint. "Professor Zwiebel sets high standards for himself and his students. At one point, his lab had as many as ten postdocs. He's trained many exceptional researchers," Feng Liu observed.
In Zwiebel's lab, Feng Liu and his junior labmate, Dr. Ye Zi, identified a specific olfactory gene in mosquitoes. When this gene was knocked out, the mosquitoes reacted more strongly to human amine compounds and lost their ability to detect the taste of blood, surviving only on nectar. Further studies showed that these "vegetarian" mosquitoes could no longer reproduce. "The myth that mosquitoes prefer type O blood isn't scientifically supported. We found that mosquitoes are attracted to strong odors and higher body temperatures, like those of people who don't bathe regularly, drink alcohol, or pregnant women. Mosquitoes need blood to lay eggs; without it, they become 'celibate'." Feng Liu chuckled.
In his spare time, Feng Liu studied mosquito larvae. "Mosquitoes lay eggs on the water surface; larvae hatch and live in the water before emerging as adults. Observing larvae in water is difficult, so there's limited knowledge on this stage," Feng Liu explained. After many attempts, he successfully recorded the neural signals of larvae. "This is the first time anyone has recorded the neural signals of aquatic mosquito larvae, proving they have strong olfactory responses, enabling them to sense their environment and find food."
Throughout his more than ten-year journey in entomology, Feng Liu has published 31 papers, 19 as the first author, in top journals like Nature Communications, Cell Reports, PNAS, and IBMB. He also secured independent funding from the National Institutes of Health (NIH). "Patience and conviction are vital in research. I'm not in a hurry for quick results. Spending time in the lab and gaining deeper insights into biological behavior each day makes me happy," Feng Liu said with a genuine smile.
04 A Laboratory for Mosquito-Borne Diseases in China
When discussing the inspiration behind setting up his own lab, Feng Liu credited his doctoral advisor, Professor Nannan Liu, with shaping his scientific journey. "When I first arrived in the United States, I was unfamiliar with everything around me. Professor Liu not only instilled in me a rigorous approach to scientific research but also cared for us like a mother. During holidays, she would cook a big feast, making us feel at home even in a foreign land. She also used her limited research funds to support our participation in conferences, helping us grow professionally. Her nurturing laid the foundation of my scientific career. Because I was treated so well, I am eager to establish my own lab and support others as she did," Feng Liu recalled.
Feng Liu chose Shenzhen Bay Laboratory (SZBL) because of its generous funding and international atmosphere as the PIs here have a lot of freedom with no interference in their research directions or distractions from trivial matters. “Biological research has no limits, and technological advances over the past decade—from new materials to microbiology, information technology and other fields—offer opportunities to push our field forward. The SZBL encourages interdisciplinary collaboration and research teams are working closely, which is rare and invaluable," he explained. Establishing a world-class mosquito-borne disease laboratory in China has always been Feng Liu's dream. "My short-term goal is to set up the lab platforms to facilitate various research directions. Long term, I want Shenzhen, China, to be mentioned alongside Rockefeller University, Vanderbilt University, and Johns Hopkins University when people talk about mosquito-borne biology. I am confident because I know I am on the right path. With enough effort, success will follow."
Over the past twenty years, Feng Liu has steadfastly pursued his passions, undeterred by external changes. From raising silkworms and bed bugs to mosquitoes, Feng Liu has always sticked to “Follow his curiosity”, moving forward with determination and resilience.
