Double-ambient CO2 concentration affects the growth, development and sucking behavior of non-target brown plant hopper Nilaparvata lugens fed on transgenic Bt rice.

Abstract

In recent years, the two issues of climate change including elevated CO2 etc., and resistance of transgenic Bt crops against non-target insect pests have received widespread attention. Elevated CO2 can affect the herbivorous insects. To date, there is no consensus about the effect of elevated CO2 on the suck-feeding insect pests (non-target insect pests of transgenic Bt crops). Its effects on the suck-feeding behavior have rarely been reported. In this study, CO2 levels were set up in artificial climate chamber to examined the effects of ambient (400 μL·L-1) and double-ambient (800 μL·L-1) CO2 levels on the suck-feeding behavior, growth, development, and reproduction of the non-target insect pest of transgenic Bt rice, brown planthopper, Nilaparvata lugens. The results showed that CO2 level significantly affected the egg and nymph duration, longevity and body mass of adults, and feeding behavior of the 4th and 5th instar nymphs, while had no effect on the fecundity of N. lugens. The duration of eggs and nymphs, and the longevity of female adults were significantly shortened by 4.0%, 4.2% and 6.6% respectively, the proportion of the macropterous adults was significantly increased by 11.6%, and the body mass of newly hatched female adults was significantly decreased by 2.2% by elevated CO2. In addition, elevated CO2 significantly enhanced the stylet puncturing efficiency of the 4th and 5th instar nymphs of N. lugens. The duration ofphloem ingestion of the N4b waveform was significantly prolonged by 60.0% and 50.1%, and the frequency significantly was increased by 230.0% and 155.9% for the 4th and 5th instar nymphs of N. lugens by elevated CO2, respectively. It was concluded that double-ambient CO2 could promote the growth and development of N. lugens through enhancing its suck-feeding, shorten the generation life-span and increase the macropertous adults' proportion of N. lugens. Thus, it could result in the occurrence of non-target rice planthopper N. lugens and make the transgenic Bt crops face with harm risk due to migration and diffusion of N. lugens under elevated CO2.