Title: | Increased EAG responses of tortricid moths after prolonged exposure to plant volatiles: evidence for octopamine-mediated sensitization |
Author(s): | Stelinski LL; Miller JR; Ressa NE; Gut LJ; |
Address: | "Department of Entomology, 205 Center for Integrated Plant Systems, Michigan State University, East Lansing, MI 48824, USA. stelinsk@msu.edu" |
DOI: | 10.1016/S0022-1910(03)00136-7 |
ISSN/ISBN: | 0022-1910 (Print) 0022-1910 (Linking) |
Abstract: | "As measured by electroantennograms (EAG), both male and female obliquebanded leafrollers, Choristoneura rosaceana (Harris), and redbanded leafrollers, Argyrotaeniavelutinana (Walker), were similarly sensitive to host-related plant volatiles: trans-2-hexenal, benzaldehyde, 1-hexenol, cis-3-hexen-1-ol, geraniol, linalool, (+)-limonene, hexenal and trans-2-hexenol. Females of both species were similarly sensitive to the shared major component of their sex-attractant pheromone ((Z)11-14:Ac). Continuous 60 min pre-exposure of male and female C. rosaceana and A. velutinana to successively higher concentrations of a mixture of the nine plant volatiles in Teflon chambers with continuous air exchange caused a dosage-dependent increase in subsequent responsiveness (sensitization) to green leaf volatiles, as measured by EAGs. In addition, 60 min of pre-exposure of male C. rosaceana to certain individual volatiles ((+)-limonene, geraniol, benzaldehyde) increased EAGs nearly as much as did the mixture of nine volatiles. Pre-exposures to the nine plant-volatile mixture at concentrations achieved by 100 microg and 1 mg loading dosages in 100 microl of mineral oil significantly increased EAG depolarization to pheromone (cross-sensitization) in males but not females of both moth species. Antennae of male C. rosaceana pre-injected with 100 microg of octopamine (OA) without volatile pre-exposure exhibited sensitization nearly identical to that induced by pre-exposing moths to sensitizing concentrations of the plant-volatile mixture. Moreover, injection of the OA antagonist chlorpromazine (CP) blocked sensitization by the plant-volatile pre-exposure. Collectively, these findings suggest that exposures of tortricid moths to certain host-plant related volatiles may modulate subsequent olfactory sensitivity to behaviorally relevant chemical cues and that plant-volatile induced sensitization may be octopamine mediated" |
Keywords: | "Adrenergic alpha-Agonists/pharmacology Animals Chlorpromazine/pharmacology Dopamine Antagonists/pharmacology Dose-Response Relationship, Drug Female Male Moths/*drug effects/*physiology Octopamine/*pharmacology Plant Extracts/*administration & dosage/chem;" |
Notes: | "MedlineStelinski, Lukasz L Miller, James R Ressa, Noah E Gut, Larry J eng Research Support, Non-U.S. Gov't England 2005/11/01 J Insect Physiol. 2003 Sep; 49(9):845-56. doi: 10.1016/S0022-1910(03)00136-7" |