Electrophysiological responses of the rice leaffolder, Cnaphalocrocis medinalis, to rice plant volatiles.

Xiao Sun,Hai-Bo Dong,Zhuang Liu,Yongmo Wang,Fang-Fang Zeng,Aijun Zhang,Xiang-Yu Pan,Man-Qun Wang,Jurgen Ziesmann

doi:10.1093/jis/14.1.70

Abstract

The rice leaffolder, Cnaphalocrocis medinalis Guenée (Lepidoptera: Pyralidae), is one of the most destructive pests of rice. Electrophysiological responses of this species to 38 synthetic volatiles known to be released from rice plants (Poaceae: Oryza spp.) were studied using the electroantennogram (EAG) method. Compounds that elicited the strongest EAG responses for each physiological condition were selected for EAG dose-response tests at five concentrations. These compounds included: methyl salicylate, heptanol, linalool, cyclohexanol, and 2-heptanone for one-day-old male moths; heptanol, hexanal, (Z)-2-hexen-1-ol, and nonadecane for one-day- old females; methyl salicylate, heptanol, (E)-2-hexen-1-ol, and (Z)-2-hexen-1-ol for three-day- old males; linalool, heptanol, (E)-2-hexen-1-ol, 2-heptanone, and hexanal for three-day-old females; 2-heptanone, cyclohexanol, linalool, heptanol, and methyl salicylate for five-day-old virgin females; and methyl benzoate, (Z)-2-hexen-1-ol, heptanol, linalool, and hexanal for five- day-old mated females. Female and male C. medinalis exhibited broad overlap in their EAG responses, and there was no clear difference between male and female EAG responses to different compounds. Statistical analyses revealed that both volatile compound chemical structure and C. medinalis physiological condition (age, sex, and mating condition) had an effect on EAG response.

Highlights

The rice leaffolder, Cnaphalocrocis medinalis Guenée (Lepidoptera: Pyralidae), is a migratory rice pest that is widely distributed in humid tropical and temperate regions of Asia, Oceania, Australia, and Africa (Khan et al 1988; Kawazu et al 2001)
This study investigates the EAG responses of C. medinalis to volatile compounds known to be released from intact rice plants (Lou et al 2005; Wechgama et al 2008; Lu et al 2010; Yan et al 2010) based on the age of males and females and the mating condition of females
For one-day-old moths, the highest EAG responses of virgin males were elicited by methyl salicylate, heptanol, linalool, cyclohexanol, and 2-heptanone

Summary

Introduction

The rice leaffolder, Cnaphalocrocis medinalis Guenée (Lepidoptera: Pyralidae), is a migratory rice pest that is widely distributed in humid tropical and temperate regions of Asia, Oceania, Australia, and Africa (Khan et al 1988; Kawazu et al 2001). It has recently become widespread throughout the major rice-growing regions of Asia and is one of the most damaging pests of rice (Poaceae: Oryza spp.) (Sogawa and Kiyota 1995; Inoue et al 2004). It is necessary to investigate the EAG responses of C. medinalis to volatile compounds known to be released from rice plants based on their physiological condition

Methods

Results

Conclusion