title: Caterpillar-induced plant volatiles attract conspecific adults in nature.
abstract: Plants release volatiles in response to caterpillar feeding that attract natural enemies of the herbivores, a tri-trophic interaction which has been considered an indirect plant defence against herbivores. The caterpillar-induced plant volatiles have been reported to repel or attract conspecific adult herbivores. To date however, no volatile signals that either repel or attract conspecific adults under field conditions have been chemically identified. Apple seedlings uniquely released seven compounds including acetic acid, acetic anhydride, benzyl alcohol, benzyl nitrile, indole, 2-phenylethanol, and (E)-nerolidol only when infested by larvae of the light brown apple moth, Epiphyas postvittana. In field tests in New Zealand, a blend of two of these, benzyl nitrile and acetic acid, attracted a large number of conspecific male and female adult moths. In North America, male and female adults of the tortricid, oblique-banded leafroller, Choristoneura rosaceana, were most attracted to a blend of 2-phenylethanol and acetic acid. Both sexes of the eye-spotted bud moth, Spilonota ocellana, were highly attracted to a blend of benzyl nitrile and acetic acid. This study provides the first identification of caterpillar-induced plant volatiles that attract conspecific adult herbivores under natural conditions, challenging the expectation of herbivore avoidance of these induced volatiles.
authors.affiliation: The New Zealand Institute for Plant &Food Research Limited, Gerald Street, 7608, Lincoln, New Zealand.
authors.forename: Ashraf M
authors.initials: AM
authors.lastname: El-Sayed
authors.affiliation: USDA-ARS, Agricultural Research Service 5230 Konnowac Pass Rd, Wapato, WA, 98951-9651, USA.
authors.forename: Alan L
authors.initials: AL
authors.lastname: Knight
authors.affiliation: Department of Entomology Robert H. Smith Faculty of Agriculture, Food and Environment The Hebrew University of Jerusalem Rehovot, Israel.
authors.forename: John A
authors.initials: JA
authors.lastname: Byers
authors.affiliation: Agriculture and Agri-Food Canada 4200 Highway 97 Box 5000, Summerland, British Columbia V0H 1Z0, Canada.
authors.forename: Gary J R
authors.initials: GJ
authors.lastname: Judd
authors.affiliation: The New Zealand Institute for Plant &Food Research Limited, Gerald Street, 7608, Lincoln, New Zealand.|School of Biological Sciences, University of Auckland Tamaki Campus, Building 733, Auckland, New Zealand.
authors.forename: David M
authors.initials: DM
authors.lastname: Suckling
mesh_terms: D019342:Acetic Acid / Q000378:metabolism / Q000494:pharmacology; D000818:Animals; D002630:Chemotactic Factors / Q000096:biosynthesis / Q000378:metabolism / Q000494:pharmacology*; D005260:Female; D060434:Herbivory / Q000187:drug effects* / Q000502:physiology; D007814:Larva / Q000187:drug effects* / Q000502:physiology; D008297:Male; D027845:Malus / Q000378:metabolism* / Q000469:parasitology; D009036:Moths / Q000187:drug effects* / Q000502:physiology; D009570:Nitriles / Q000378:metabolism / Q000494:pharmacology; D010626:Phenylethyl Alcohol / Q000378:metabolism / Q000494:pharmacology; D036226:Seedlings / Q000378:metabolism / Q000469:parasitology; D055549:Volatile Organic Compounds / Q000378:metabolism / Q000494:pharmacology*
chemical_list: D002630:Chemotactic Factors; D009570:Nitriles; D055549:Volatile Organic Compounds; D010626:Phenylethyl Alcohol; D019342:Acetic Acid