In a new study, researchers at the University of California, Berkeley, have shown how a bacterium called Wolbachia pipientis infects female mosquitoes and then kills their male offspring. The bacteria do this by invading the ovaries of the female mosquitoes and disrupting the development of the male embryos.
"This is the first time that male-killing has been definitively linked to a bacterial infection," said Omar Akbari, a postdoctoral fellow in the Department of Environmental Science, Policy, and Management at UC Berkeley and the lead author of the study. "Our findings provide new insights into the evolution of sex ratios and the role of bacteria in shaping the natural world."
Wolbachia pipientis is a widespread bacterium that infects a variety of insects, including mosquitoes, fruit flies, and butterflies. In some cases, the bacteria can cause cytoplasmic incompatibility, a condition in which the chromosomes of the male and female parents do not match up properly, leading to the death of the embryo.
In the new study, Akbari and his colleagues showed that Wolbachia pipientis can also cause male-killing in mosquitoes by infecting the female ovaries and disrupting the development of the male embryos. The bacteria do this by producing a toxin that kills the male embryos at a specific stage of development.
The researchers believe that male-killing may have evolved in Wolbachia pipientis as a way to increase the transmission of the bacteria from one generation to the next. By killing male offspring, the bacteria can ensure that their infected female offspring will mate with uninfected males, thus spreading the bacteria to new populations.
"Our findings suggest that male-killing may be a more common phenomenon in bacteria than previously thought," said Akbari. "This discovery opens up new avenues of research into the evolution of sex ratios and the role of bacteria in shaping the natural world."
The study was published in the journal Nature Communications.
