Some researchers are elated over whiteflies, whose eggs develop faster due to infection by certain bacteria,
“It’s instant evolution,” said Molly Hunter, a professor of entomology in the UA’s College of Agriculture and Life Sciences and the study’s principal investigator. “Our lab studies suggest that these bacteria can transform an insect population over a very short time.” – “Instant Evolution in Whiteflies: Just Add Bacteria”, ScienceDaily (Apr. 8, 2011)
One outcome is more female whiteflies, for reasons presently unclear.
The fly is a pest, when present in large numbers, which the bacteria are believed to augment:
“Here in Arizona, it probably starts out on weeds in the spring, and then moves on to melons, and when melons are done, it moves in big numbers onto cotton and feeds on that all summer long,” Hunter explained. “In the fall, it moves on to vegetables, and so it just keeps going.”
Apart from bigger hordes in the short term, it is unclear where the evolution part comes in.
And, from New Scientist, we learn:
Sweet-potato whitefly was a huge problem for farmers in the south-western US two decades ago, when fields would be besieged by huge clouds of the pests. Today, it is under much stronger control, and if Rickettsia and whitefly are preparing a comeback, there are no signs of it yet.”So far we haven’t gotten any reports from local farmers of clouds of whiteflies,” Himler says. “If Rickettsia is increasing the whitefly’s fitness in the wild, it’s possible that predators or environmental factors are dampening the effect.”
– Ferris Jabr, “Evolutionary tug of war inside sweet-potato whitefly”, 07 April 2011
Hmmm. If evolution is to happen, it must certainly get control of that.