Effects of temperature on mate location in the planthopper, Nilaparvata lugens (Homoptera: Delphacidae).

The planthopper, Nilaparvata lugens Stål (Homoptera: Delphacidae), uses acoustic signals generated by abdominal vibration and transmitted through rice (Oryza sativa L.) plants to locate mates. The influence of temperature (20, 28, and 32°C) on abdominal vibration patterns of individual females and males, proportion of mated females, and responsivity of male to female vibrational signals was investigated. When female and male adults were observed individually, temperatures of 20 and 32°C inhibited abdominal vibration by both genders in terms of proportion of vibrating insects, time spent in vibration per insect, time spent per bout of vibration, or all of these; the effects were more pronounced at 32°C than at 20°C especially in males at 32°C. Although not significantly different, male responsivity to vibrating female was relatively high at 28°C, lower at 32°C, and still lower at 20°C, and finally more males located females at 28°C than at 20°C, which contributes to the higher proportion of mated females at 28°C than at 20 or 32°C. Our results indicate that temperatures of 20 and 32°C inhibit the production of abdominal vibration and, to some extent, reduce male responsivity to female vibrational signals, which may partially explain the frequent population outbreaks in N. lugens in the years with warm autumn.