The scientists point to the possibility that proteins responsible for activating sperm in mosquitoes could be turned off, preventing them from swimming or fertilizing eggs. This could help control populations of Culex, the common household mosquito that transmits cerebral encephalitis and West Nile virus.
During mating, mosquitoes mate tail to tail and males transfer sperm into the female’s reproductive tract. It can be stored there for a while, but to complete fertilization it has to complete the journey. The key is the specialized proteins that are secreted during ejaculation and that activate the flagella, or “tails,” of the sperm, which direct its movement. Without these proteins, sperm cannot penetrate the eggs. They will remain immobile and would eventually degrade.
Researchers at the University of California at Riverside published their study in PLOS ONE journalwith a comprehensive picture of all the insect sperm proteins, allowing researchers to find the specific ones that maintain sperm quality while they are inactive and also activate them to swim.
To obtain this detailed information, the research team worked with a group of undergraduate and graduate students who isolated up to 200 male mosquitoes from a larger population. Then they extracted enough sperm from the tiny reproductive tracts for the mass spectrometry equipment to detect and identify the proteins.
Previously, the team had determined that sperm need calcium upon entering the reproductive tract to fuel their forward movement. This allowed them to find the calcium channel proteins and design experiments targeting these channels.
This type of protein profile offers a greener path to mosquito control than other methods that can have unwanted toxic effects, such as insecticides that kill other animals, especially essential bees.
Mosquitoes are the deadliest animals on Earth, killing over half a million people a year due to the diseases they carry. As climate change intensifies, many more mosquitoes, such as those that carry malaria, are migrating to the northern hemisphere. The key word is controlling mosquitoes, not eradicating them. Sperm immobilization would change the ratio of fertile to infertile males in a given mosquito population, rather than killing them all.
REFERENCE
Using the Culex pipiens sperm proteome to identify elements essential for mosquito reproduction