Caterpillars shouldn’t always trust their guts. A new study reports that stomach microbes can betray their pest hosts, conspiring with Bt toxin to kill the lepidopteran larvae.The findings, released online March 3 in BMC Biology, reveal “a new realm of exciting interactions that we didn’t anticipate,” comments entomologist Bruce Tabashnik of the University of Arizona in Tucson.A greater understanding of the interactions among the toxin, the pests it kills and their gut microbes may lead to desig