Electrical penetration graph (EPG) waveforms in relation to feeding behavior of Laodelphax striatellus

Key Words：Laodelphax striatellus; Electrical penetration graph; feeding behavior; instar; sex

Abstract：The relationship between EPG waveforms and the stylet penetration behavior of Laodelphax striatellus was evaluated through the use of an technique. The EPG parameters of different instars and sex L. striatellus were also compared. The results showed that the EPG signals of the small brown planthopper were classified into seven different waveforms, NP, N1, N2-a，N2-b，N3, N4, and N5. They were almost similar to those in Nilaparvata lugens according to their shapes, amplitude, and frequencies. A new special waveform was first identified in the salivation phase of N2. It can be divided into two parts, including N2-a and N2-b. N2-a means salivation and stylet movement, and N2-b means sustained salivation. EPG waveforms of L. striatellus were similar among different instars and sex. However, their EPG parameters were different. Females showed higher probe frequency than that of males and young nymphs. The periods of extracellular movement of adults’ stylets near the phloem regionwere longerthan that of nymph.