高温对共存种棉蚜与棉长管蚜死亡及繁殖的影响

棉蚜和棉长管蚜是棉花上的共存种,为探索其年内及年际间优势地位的不同是否与两者对高温的不同响应有关,室内研究了高温胁迫(32、34、36和38℃)对棉蚜和棉长管蚜死亡及繁殖的影响.结果表明:随着温度的升高和高温持续天数的延长,棉蚜和棉长管蚜累计死亡率均升高,棉长管蚜累计死亡率高于棉蚜;两种蚜虫的每日死亡率可用互补重对数模型较好地拟合,模型估计的棉蚜和棉长管蚜半数致死温度值随高温持续天数的延长而降低,棉蚜半数致死温度高于棉长管蚜;在32 ～ 38℃范围内,两种蚜虫的繁殖率随温度的升高而降低,棉蚜繁殖率显著高于棉长管蚜,表明在32℃以上高温条件下,棉蚜比棉长管蚜更具有竞争力.随着全球气候变暖,由于棉蚜比棉长管蚜更耐高温,推测未来棉蚜比棉长管蚜竞争优势更加明显.

Effects of high temperature on the mortality and fecundity of two co-existing cotton aphid species Aphis gossypii Glover and Acyrthosiphon gossypii Mordvilko

Aphis gossypii and Acyrthosiphon gossypii are the coexisting species on cotton plant, with their abundance differed within and among years. To explore whether the abundance difference was related to the different responses of the two aphid species to high temperature, a laboratory experiment was conducted to assess the mortality and reproduction of the two aphid species at high temperatures 32, 34, 36 and 38 degrees C. With the increasing temperature and prolonged exposure period, the cumulative mortality of the two aphid species increased, and Acyrthosiphon gossypii had a higher cumulative mortality than Aphis gossypii. The daily mortality of the aphids could be well simulated by complementary log-log (CLL) model. The median lethal temperature of the two aphid species estimated by CLL model decreased with prolonged exposure period. Under the same exposure period, the median lethal temperature of Aphis gossypii was higher than that of Acyrthosiphon gossypii. Within the range of 32-38 degrees C, the reproduction rate of the two aphid species decreased with increasing temperature, but Aphis gossypii had a significantly higher reproduction rate than Acyrthosiphon gossypii, indicating that at the temperature higher than 32 degrees C, Aphis gossypi had higher tolerance against high temperature than Acyrthosiphon gossypii, and consequently, had more competitive advantage under global warming.