Scientists unravel the mysteries of "malaria mosquito" marriage and courtship

On January 22, a latest study by Wang Sibao's team, a researcher at the Center for Excellence in Molecular Plant Science of the Chinese Academy of Sciences, was published online in Science. The results reveal the molecular mechanism of anopheles swarm marriage flight and the mystery of chemical communication between male and female courtship.

Among mosquitoes, female mosquitoes need blood to supplement nutrition in order to lay eggs and reproduce offspring, while male mosquitoes feed on plant sap or nectar. There are three main types of common mosquitoes: Anopheles, Aedes mosquitoes and Culex mosquitoes. Among them, Anopheles mosquitoes, also known as Anopheles mosquitoes, are mainly active at night and are the vector of malaria.

At dusk in summer, male Anopheles mosquitoes gather in flocks to fly in the air, attract females to fly in and then courteously mating, a phenomenon known as marriage flying. Although mosquito marriage flight has long been recorded, the molecular mechanism of Anopheles marriage flight and courtship mating has not yet been elucidated. Wang Sibao's team used multidisciplinary and interdisciplinary research methods to reveal the mechanism of anopheles marriage flight and mating.

By comparing and analyzing the gene expression of the head of the married and unmarried male Anopheles mosquitoes collected in the wild, the researchers found that the expression of the two biological clock core genes per and tim in the head of the married male mosquito was significantly upregulated. Reducing the expression of per or tim significantly inhibits the marriage flight of male mosquitoes, thereby reducing mating rates. In addition, the researchers also found that continuous light in the evening and unsuitable ambient temperature can affect the marriage flight and mating activity of Anopheles mosquitoes, and this effect is achieved by regulating the expression of the circadian clock gene per and tim.

Communication and mate selection between insects relies primarily on sexual pheromone communication, a trace chemical that can induce individuals of the same sex to copulate, as do Anopheles mosquitoes. However, the chemical language of male mosquitoes courting female mosquitoes in marriage flights, "sex pheromones", is still an unsolved mystery. Through gene expression profiling, the researchers found that the expression of the gene desat1 in the marriage flying male mosquito was significantly upregulated. Interference inhibits the expression of desat1 also affects Anopheles marriage flight and mating behavior. Further studies found that the expression of desat1 was rhythmic oscillation and regulated by the light and clock genes per and tim, indicating that desat1 is a clock control gene regulated by light signals.

In order to verify whether per, tim, and desat1 also regulate the marriage flight and mating behavior of the African malaria vector, Anopheles gambian mosquitoes, Wang Sibao's team collaborated with American scholars to confirm that the core circadian clock gene (per, tim) and the bell control gene desat1 have the same function in regulating the marriage flight and mating of different Anopheles mosquitoes. In addition, in collaboration with an international research team, they conducted outdoor testing studies in Burkina Faso, confirming the function and role of the circadian clock gene in regulating the marriage and mating behavior of Anopheles mosquitoes in the outdoor natural environment.

Experts said that the study has promoted people's understanding of the mechanism of marriage flight and courtship mating of Anopheles mosquitoes, and also provided new ideas and methods for the development of green mosquito prevention and control technologies. For example, by manipulating mosquito marriage and flight to interfere with mating or concentrated booby-trapping, using sexual pheromones to enhance the sexual attraction and mating competitiveness of male mosquitoes to female mosquitoes in the wild to trap female mosquitoes. (Huang Xin)

Source: China Science Daily