Center for Insect Science, The University of Arizona, Post Office Box 210106, Tucson, AZ 85721-0106, USA.
Science. 2011 Apr 8;332(6026):254-6. doi: 10.1126/science.1199410.
Maternally inherited bacterial symbionts of arthropods are common, yet symbiont invasions of host populations have rarely been observed. Here, we show that Rickettsia sp. nr. bellii swept into a population of an invasive agricultural pest, the sweet potato whitefly, Bemisia tabaci, in just 6 years. Compared with uninfected whiteflies, Rickettsia-infected whiteflies produced more offspring, had higher survival to adulthood, developed faster, and produced a higher proportion of daughters. The symbiont thus functions as both mutualist and reproductive manipulator. The observed increased performance and sex-ratio bias of infected whiteflies are sufficient to explain the spread of Rickettsia across the southwestern United States. Symbiont invasions such as this represent a sudden evolutionary shift for the host, with potentially large impacts on its ecology and invasiveness.
节肢动物的母系遗传细菌共生体很常见，但共生体对宿主种群的入侵却很少被观察到。在这里，我们表明，贝氏里克氏菌（Rickettsia sp. nr. bellii）在短短 6 年内席卷了入侵农业害虫——甘薯粉虱（Bemisia tabaci）的一个种群。与未感染的粉虱相比，感染了贝氏里克氏菌的粉虱繁殖更多的后代，成虫存活率更高，发育更快，产生更多的雌性后代。因此，这种共生体既是共生体又是生殖操纵者。感染粉虱的表现和性别比例偏差的增加足以解释这种共生体在美国西南部的传播。像这样的共生体入侵代表了宿主的突然进化转变，可能对其生态学和入侵性产生巨大影响。
