Bacteria turn whitefly into superbug

In a case of rapid evolution, Univ. of Ariz. scientists found that Rickettsia bacteria give whiteflies an edge over their uninfected peers. Sweet potato whitefly (Bemisia tabaci) infected with the bacteria lay more eggs, develop faster and are more likely to survive to adulthood compared to uninfected whitefly. The findings were published in the April 8 issue of Science.
“It’s instant evolution,” said Univ. of Ariz. entomologist Molly Hunter. “Our lab studies suggest that these bacteria can transform an insect population over a very short time. It is not uncommon to find a microbe providing some benefits to their hosts, but the magnitude of fitness benefits we found is unusual.”
In addition to the observed evolutionary advantages, called fitness benefits, the researchers discovered that the bacteria manipulate the sex ratio of the whiteflies’ offspring by causing more females to be born than males. Since the bacteria are transmitted only from mother to offspring, Hunter said it is beneficial for them to make sure more female than male whiteflies are born.