Lufenuron-suppressed disease resistance of Formosan subterranean termites (Isoptera: Rhinotermitidae) to bacterial pathogens

It is well established that pesticides can negatively affect insect immunity. Although studies show that Formosan subterranean termites, Coptotermes formosanus Shiraki, are resistant to microbial infections, pesticide effect on disease resistance is little studied. In this study, C. formosanus previously fed lufenuron was exposed to three species of bacteria, Pseudomonas aeruginosa, Serratia marcescens, and Bacillus thuringiensis (subspecies israelensis). We found that termite mortality was significantly higher in the combination of lufenuron and P. aeruginosa. Interestingly, only in treatments without lufenuron (versus bacteria alone or controls) did termites show carcass-burying behavior. The results indicate that lufenuron, a chitin synthesis inhibitor, can suppress Formosan termite disease resistance to P. aeruginosa. Our data suggest a chitin synthesis inhibitor with a bacterial pathogen may be a significant improvement in bait technology.