The findings, published April 17 in the journal Nature Microbiology, help explain why some bacterial infections are more common in males than in females and how bacteria have evolved to manipulate their hosts’ reproductive systems.
The researchers focused on two bacterial species, _Wolbachia_ and _Rickettsia_. _Wolbachia_ is found in up to 65% of all insect species and some spiders and crustaceans. It is also found in filarial nematodes, which are parasitic roundworms that cause diseases such as elephantiasis and river blindness in humans. _Rickettsia_ is found in ticks, fleas, and lice, and it causes diseases such as Rocky Mountain spotted fever and typhus.
Both _Wolbachia_ and _Rickettsia_ can be transmitted from mothers to offspring through the eggs. When the bacteria colonize the mother’s reproductive organs, they can produce a toxin that targets male embryos and fetuses. The toxin causes the embryos and fetuses to abort, or it can cause them to be born with defects.
The study’s findings suggest that _Wolbachia_ and _Rickettsia_ have evolved to manipulate their hosts’ reproductive systems to increase their own chances of survival and transmission. By killing male offspring, the bacteria reduce the competition for resources among their own offspring. They also increase the chances that their offspring will be transmitted to new hosts.
The findings also have implications for human health. Some bacterial infections, such as chlamydia and gonorrhea, are known to be more common in males than in females. The new study suggests that these infections may be more common in males because the bacteria that cause them have evolved to target male reproductive organs.
The study’s authors say that further research is needed to investigate the role of bacteria in causing male infertility and other reproductive health problems. They also say that the findings could lead to new ways to prevent and treat bacterial infections.
