Effects Of Temperature On Growth And Development Of The Brown Planthopper, Nilaparvata Lugens (Homoptera: Delphacidae)

The brown planthopper, Nilaparvata lugens (Stal), is one of the most serious and destructive pests of rice in Asia. Climate warming in tropical regions and extreme-high- or low-temperature events may become limiting factors affecting the survival and distribution of N. lugens.The effects of continuous high temperature (CHT), discontinuous high temperature (DHT), and abnormal low temperature in summer (ALT) on the growth and development of N. lugens were studied under lab conditions. High temperatures and ALT decreased the survival rate of nymphs (in fourth-instar nymphs, CHT, DHT, ALT, and control survival was 46.67% +/- 1.67, 31.67% +/- 1.67, 48.33% +/- 4.41, and 60.00% +/- 2.89, respectively, P< 0.05). ALT also prolonged the development of N. lugens nymphs (in fourth-instar nymphs, ALT and control survival was 6.09 +/- 0.193 d and 5.39 +/- 0.082 d, respectively, P< 0.05). In fifth-instar nymphs, CHT (2.36 +/- 0.064 d, P< 0.05) and DHT (2.34 +/- 0.048 d, P< 0.05) had little influence on nymphal development compared with the control (2.25 +/- 0.012 d, P < 0.05). The three temperature treatments (CHT, DHT, and ALT) decreased the number of eggs produced (61.33 +/- 0.067, 62.67 +/- 0.882, and 34.00 +/- 0.577, respectively, P< 0.05) compared with the control (68.00 +/- 1.000, P< 0.05).The female sex ratio decreased after nymphs were subjected to CHT (65.82% +/- 0.771, P< 0.05, in fifth-instar nymphs) and ALT (76.01% +/- 1.362, P< 0.05) compared with the control (81.63% +/- 1.007, P< 0.05). Adults in CHT (25.30 +/- 0.182, P< 0.05) and DHT (14.64 +/- 0.238, P< 0.05) consumed significantly more food than the control (11.54 +/- 0.181, P< 0.05), but adults in ALT (6.54 +/- 0.196, P< 0.05) fed significantly less than the control (11.54 +/- 0.181, P< 0.05). Hatching rates of eggs under the three temperature treatments (CHT, DHT, and ALT were 69.57% +/- 0.215, 71.29% +/- 0.529, and 43.13% +/- 0.508, respectively, and were significantly lower (P< 0.05) than the control (78.95% +/- 1.000, P< 0.05).These experiments revealed that extreme temperatures can influence the growth and development of N. lugens and may affect its distribution. As such, N. lugens remains a serious pest of rice.