Imperial College leads the science news today with a paper published in Proceedings of the National Academy of Sciences reporting on their work sterilising male mosquitoes without the females’ knowledge.

Anopheles gambiae, the species primarily responsible for the spread of malaria in Africa and currently under investigation at Imperial College, London

Researchers from Imperial’s Department of Life Sciences and Oxford’s Department of Zoology injected ordinary mosquito eggs with a protein which interfered with testes development in males, producing 100 spermless, but otherwise unaffected male mosquitoes. Results suggested that not only were females unable to tell sterile males from fertile ones, but that they did not subsequently seek another mate.

After mating for the first and only time in her life, the female mosquito undergoes certain physiological changes, then eats a blood meal and lays a batch of eggs. In the new experiments, the researchers observed that this behaviour was the same regardless of whether or not the mating encounter had produced fertilised eggs that could hatch into mosquito larvae.

The scientists were also surprised to discover that after mating with a spermless male, the female made no attempt to find a supplementary mate, effectively missing out on the opportunity to reproduce and pass on her genes. They expected to find that the species had evolved a mechanism so that females could avoid or bypass sterile males. For example, female fruit flies can mate with more than one male, helping to ensure their eggs are fertilised.

Malaria affects 300 million people worldwide every year and lead author, Dr Flaminia Catteruccia of Imperial College, said: "In the fight against malaria, many hope that the ability to genetically control the mosquito vector will one day be an key part of our armoury.