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Research article - Peer-reviewed, 2021

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

Revadi, Santosh V.; Giannuzzi, Vito Antonio; Vetukuri, Ramesh R.; Walker, William B., III; Becher, Paul G.;

Abstract

Larval frass in herbivorous lepidopterans is mainly composed of plant-derived material and microbes from the gut. Despite the fact that frass from conspecific larvae repels female moths in Spodoptera littoralis from oviposition, the role of frass volatiles on larval foraging behavior is largely unknown. Here, we show that larvae of S. littoralis walk upwind to larval frass volatiles in a wind tunnel assay. We identified the frass volatile guaiacol (2-methoxyphenol) as key ligand for the S. littoralis odorant receptor (OR) SlitOr59 which we expressed heterologously. We isolated guaiacol-producing bacteria identified as Serratia marcescens from frass of larvae that were fed on cotton, and Enterobacter cloacae, E. ludwigii and Klebsiella sp. from frass derived from cabbage-fed larvae. In addition to guaiacol, we also identified volatiles acetoin, 3-methyl-1-butanol and dimethyl disulfide, in large proportions in headspace collections from the bacteria. A Y-tube olfactometer assay showed that fourth instar S. littoralis larvae are attracted to guaiacol. Moreover, cotton leaves treated with the insecticide Spinosad and guaiacol were highly attractive to the larvae. Our results provide a basis for management of the pest by directly targeting larvae, based on an attract-and-kill strategy. Further studies are needed to test the application of guaiacol for semiochemical-based pest management of Spodoptera pest species.

Keywords

Bacteria; Caterpillar; Electrophysiology; Frass volatiles; Lepidoptera; Migration; Odorant receptor; Olfactometer

Published in

Journal of Pest Science

2021, volume: 94, number: 4, pages: 1105-1118
Publisher: SPRINGER HEIDELBERG

Authors' information

Swedish University of Agricultural Sciences, Department of Plant Protection Biology
Giannuzzi, Vito Antonio (Giannuzzi, Vito Antonio )
Swedish University of Agricultural Sciences, Department of Plant Protection Biology
Vetukuri, Ramesh (Ramesh, Vetukuri)
Swedish University of Agricultural Sciences, Department of Plant Breeding
Walker, William B. (Walker, William B.)
Swedish University of Agricultural Sciences, Department of Plant Protection Biology
Swedish University of Agricultural Sciences, Department of Plant Protection Biology

UKÄ Subject classification

Agricultural Science

Publication Identifiers

DOI: https://doi.org/10.1007/s10340-021-01352-9

URI (permanent link to this page)

https://res.slu.se/id/publ/111408