Pulling the ‘mating plug’ may reduce mosquito population and malaria rates

Interfering in mosquitoes’ sex lives could help halt the spread of malaria, British scientists said this week.

A study on the species of mosquito mainly responsible for malaria transmission in Africa, Anopheles gambiae, showed that because these mosquitoes mate only once in their lives, meddling with that process could dramatically cut their numbers.

Researchers from Imperial College London found that a “mating plug” -- used by male mosquitoes to ensure their sperm stays in the right place after mating -- is essential for the fertilization of eggs during the female’s lifetime.

Without the mating plug, sperm is not stored properly and fertilization is disrupted, the researchers wrote in the study published Tuesday in the journal PLoS Biology.

“Removing or interfering with the mating plug renders copulation ineffective,” wrote Flaminia Catteruccia of the university’s life sciences department. “This discovery could be used to develop new ways of controlling populations of Anopheles gambiae mosquitoes, to limit the spread of malaria.”

About 40% of the world’s population is at risk of malaria, a potentially deadly disease transmitted via mosquito bites. It kills more than a million people worldwide each year, and children account for about 90% of the deaths in the most heavily affected areas of sub-Saharan Africa and parts of Asia.

Catteruccia’s team analyzed the composition of the mating plug and found that it is formed when an enzyme called transglutaminase interacts with proteins in the male mosquito’s seminal fluid. This interaction causes the fluid to clot into a gelatinous solid mass.

When the researchers knocked out the enzyme in male mosquitoes, the plug could not form and reproduction failed.

If this process could be developed for use in the field, perhaps in a spray form like an insecticide, it could “effectively induce sterility in female mosquitoes in the wild,” Catteruccia wrote, potentially offering “one more weapon in the arsenal against malaria.”

Health experts advocate a multipronged approach to fighting malaria, combining preventive measures such as insecticides and bed nets with improved access to the best drug treatments in the most high-risk areas.

The World Health Organization recently said that increased funding was starting to pay off in the battle against the disease.