In 2017, researchers discovered that the oriental fruit fly (Bactrocera dorsalis) had developed resistance to the insecticide trichlorphon thanks to a species of symbiotic bacteria, Citrobacter freundii, in its gut that helps the fly degrade the chemical. A new review paper published in the Annals of the Entomological Society of America compiles this case and other existing research on the links between insect symbionts and insecticide resistance. (Merle Shepard, Gerald R.Carner, and P.A.C Ooi, Insects and their Natural Enemies Associated with Vegetables and Soybean in Southeast Asia, Bugwood.org)