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The brown planthopper, Nilaparvata lugens (Stål), 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. [ABSTRACT FROM AUTHOR]

Ophraella communa LeSage (Coleoptera: Chrysomelidae) is an important biological control agent of the common ragweed, Ambrosia artemisiifolia L., in China. Development and fecundity of O. communa, and hatch rate of progeny eggs were studied at five photoperiods (8:16, 10:14, 12:12, 14:10, and 16:8 [L:D] h). The highest survival rate of eggs was 92% at the photoperiod of 16:8 (L:D) h, and those of both larvae and pupae were observed at the photoperiod of 14:10 (L:D) h (85 and 96%). The shortest developmental durations of larvae and pupae were observed at photoperiods of 14:10 and 16:8 (L:D) h. Fecundity was 1,159-1,976 eggs per female from photoperiods of 8:16 to 16:8 (L:D) h. The hatch rates of progeny eggs were 67-92% from photoperiods of 8:16 to 16:8 (L:D) h, and photoperiods did not affect developmental duration of progeny eggs. The intrinsic rate for increase ( r), the net reproductive rate ( R0), and the finite rate of increase (λ) reached the maximum values at 16:8 (L:D) h (0.2219 d-1, 721 hatched eggs and 1.2484 d-1, respectively) and 14:10 (L:D) h (0.2133 d-1,605.6 hatched eggs and 1.2378 d-1, respectively). Their minimum values were observed at the photoperiod of 8:16 (L:D) h, which were 0.1731 d-1, 212.2 hatched eggs and 0.1890 d-1, respectively. The shortest T value was 29.7 d at a photoperiod of 16:8 (L:D) h and the longest was 31.4 d at a photoperiod of 12:12 (L:D) h. Our study shows that O. communa could survive and reproduce successfully at different photoperiods, thus may expand its distribution to regions with different photoperiods. [ABSTRACT FROM AUTHOR]