Abstract: 【Aim】 There are long-winged and short-winged morphs in populations of the small brown planthopper (SBPH), Laodelphax striatellus. The wing morphs of SBPHs are affected by the genetic and environmental factors. The aim of this study is to illustrate the adaptability of the long-winged and short-winged strains of SBPHs to high and low temperatures. 【Methods】 The selection of long-winged and short-winged strains in SBPHs was performed under a constant condition, and the strains with long and short wings were set up after 63 and 65 generations of selection, respectively. The fecundity, survival rates and developmental duration of populations of the long-winged and short-winged strains and a wild population collected from rice filed in Nanjing were measured at 25, 30 and 35℃. The survival rates of nymphs of these three populations were measured after exposure to 5℃ and -20℃. The supercooling points of nymphs and adults of these three populations were also measured. The adaptability of long-winged and short-winged strains to high and low temperatures was analyzed by comparing the survival rate, developmental duration, fecundity and supercooling point. 【Results】 The fecundity of the female adults of the long-winged and short-winged strains of SBPH was significantly lower than that of the wild population at 25, 30 and 35℃, and there was no significant difference in the fecundity between the short-winged and long-winged strains. The fecundity of the female adults of the short-winged or long-winged strain at 25℃ was not significantly different than that at 30℃, but the fecundity of the female adults of the wild population at 25℃ was significantly higher than that at 30℃. At 35℃, the short-winged and long-winged strains hardly produce nymphs. The nymphal survival rate at 25℃ was similar among the short-winged strain, long-winged strain and wild population. But at 30℃, the nymphal survival rate of the short-winged strain was significantly lower than that of the wild population, and there was no significant difference in the nymphal survival rate between the short-winged and long-winged strains. At 35℃, the nymphs of the short-winged and long-winged strains only survived to the 3rd instar, but the nymphs of the wild population could survive to the 5th instar. The nymphal duration of the short-winged strain at 25℃ was significantly shorter than that of the wild population, but did not differ from that of the long-winged strain. At 30℃, however, the nymphal duration of the short-winged strain was significantly longer than those of the long-winged strain and the wild population. The survival days of the 3rd-4th instar nymphs of the long-winged strain were not different from those of the short-winged strain and the wild population at 5℃. The mortality rates of nymphs of the long-winged strain and the short-winged strain after exposure to -20℃ for 10 min showed no significant difference, but were significantly higher than that of the wild population. The supercooling points of adults were not significantly different among the short-winged strain, long-winged strain and wild population. However, the supercooling point of the 5th instar nymphs of the short-winged strain was significantly higher than that of the wild population, but showed no significant difference from that of the long-winged strain. 【Conclusion】 The adaptability of the long-winged and short-winged strains of SBPH to high and low temperatures is similar but lower than that of the wild population. The nymphal development of the short-winged strain of SBPH is slower than that of the long-winged strain under conditions of high temperature.

Key words: Laodelphax striatellus, wing morph, temperature, survival rate, developmental duration, fecundity, cold tolerance