低温胁迫对灰飞虱种群生长发育与繁殖的影响

为了探讨低温在灰飞虱Laodelphax striatellus(Fallén)种群发生发展中的作用,本文以南京冬季的旬平均最低温为依据,设定出-6～2℃的低温,研究了用该低温处理3～4龄若虫不同时间后,灰飞虱的存活、生长与繁殖特性。结果表明,灰飞虱3～4龄若虫有较强的耐低温能力,-6～2℃的温度下,其半致迷和半致死时间分别为1.22和20.49d。低温抑制了若虫的生长发育,发育历期明显延长。低温处理后成虫的性比有所提高,并且短翅率显著增加。3～4龄若虫低温处理1～7d后羽化的成虫有产卵前期缩短、寿命延长的趋势,但对繁殖力没有显著影响,并且低温处理2d后的产卵量要稍高于没有处理的对照。由此可见,-6～2℃低温的短期胁迫对灰飞虱种群的发生发展不会产生抑制作用。

Effect of low temperature shock on the development and fecundity of Laodelphax striatellus (Fallén)

In order to explore the effect of low temperature on the development of the small brown planthopper（SBPH）,the survival,development and fecundity of SBPH were studied in the laboratory at a temperature similar to the average winter temperature in Nanjing（-6-2℃）.The results indicate that 3rd and 4th instar nymphs were relatively cold resistant with median knockdown and lethal times of 1.22 and 20.49 days,respectively.Cold shock inhibited nymphs＇ development.There was a significant difference in the sex ratio of SBPH exposed to cold temperatures for 4 days and the control group.The rate of adult brachyptery increased significantly with duration of exposure to cold temperatures whereas the preoviposition period tended to decline and adult longevity tended to increase.However,the subsequent fecundity of 3-4th instar nymphs was not affected by duration of exposure to cold.Furthermore,the number of eggs produced by nymphs subject to two days at cold temperature slightly exceeded that of the control group.The results suggest that short-term exposure to cold temperatures do not significantly retard the population development of SBPH.