Larval response to frass and guaiacol: detection of an attractant produced by bacteria from Spodoptera littoralis frass

Abstract Larval frass in herbivorous lepidopterans is mainly composed of plant-derived material and microbes from the gut. Despite fact that conspecific larvae repels female moths Spodoptera littoralis oviposition, role volatiles on larval foraging behavior largely unknown. Here, we show S. walk upwind to a wind tunnel assay. We identified volatile guaiacol (2-methoxyphenol) as key ligand for odorant receptor (OR) Slit Or59 which expressed heterologously. isolated guaiacol-producing bacteria Serratia marcescens were fed cotton, Enterobacter cloacae, E. ludwigii Klebsiella sp. derived cabbage-fed larvae. In addition guaiacol, also acetoin, 3-methyl-1-butanol dimethyl disulfide, large proportions headspace collections bacteria. A Y-tube olfactometer assay showed fourth instar are attracted guaiacol. Moreover, cotton leaves treated with insecticide Spinosad highly attractive Our results provide basis management pest by directly targeting larvae, based an attract-and-kill strategy. Further studies needed test application semiochemical-based species .