Mosquitoes can be stopped from reproducing by deactivating their sperm, according to a new study by scientists in California. By making changes to the proteins that regulate these processes, the insects lose their ability to fertilize eggs. Scientists want to use this method to control the population of mosquitoes that spread serious diseases.
As the World Health Organization explains, mosquitoes contribute to the deaths of hundreds of thousands of people each year – far more than any other animal. These insects are carriers of many serious diseases, including malaria, dengue fever and chikunguni. For this reason, scientists have been looking for the most effective ways to control mosquito populations for years, which would slow the spread of diseases and save thousands of lives. A new, potential method of combating nuisance insects has been presented in the “PLOS ONE” magazine.
Complicated fertilization process
For the study, researchers from the University of California, Riverside used 200 male buzzing mosquitoes (Culex pipiens) – a common species found in tropical, subtropical and temperate countries, including Poland. He is a potential carrier of the West Nile virus. The researchers extracted enough sperm from their reproductive tracts to be used for mass spectrometry. From this, the team analyzed the full protein composition of insect germ cells.
The researchers then focused on finding the molecules responsible for activating male sex cells. As Cathy Thaler, the lead author of the study, explains, during mating, male mosquitoes introduce inactive, immobile sperm into the reproductive tracts of females. They must independently reach the egg cells, which is helped by the whips, i.e. moving “tails”. Proteins secreted during ejaculation are responsible for their activation – they have become the goal of researchers.
– Without these proteins, sperm cannot penetrate the eggs. They will remain stationary and eventually disintegrate, explains Richard Cardullo, co-author of the study.
Previously, the research team had determined that sperm needed calcium ions to move. ‘Now we can look at the protein profile we created, find those from the calcium channels and design experiments to induce changes in these structures,’ added Cardullo.
Control, not elimination
Inactivation of proteins could be used to control mosquito populations in the future. As the scientists explain, this method is more environmentally friendly than many other means that we use in the fight against nuisance mosquitoes.
“We have refrained from mass spraying of pesticides because they kill all insects, both beneficial and pest, and also harm other animals,” Thaler comments.
The authors emphasize that it is necessary to control the mosquito population, not to completely eliminate it. Even if sperm immobilization were effective in all mosquitoes, their extermination would not be desirable at all.
“Mosquitoes are the deadliest animals on Earth,” Cardullo explains. – But while the vast majority of people hate them, most environmentalists would oppose a plan to eliminate them altogether. They play an important role in the food chain.
The team hopes that the method of regulating the fertility of the buzzing mosquito will work for other species as well. As climate change intensifies, many mosquitoes, including the malaria-carrying Antrum, are moving closer and closer to temperate zones, including Europe.
University of California-Riverside, WHO
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