昆虫学报 ›› 2022, Vol. 65 ›› Issue (10): 1314-1323.doi: 10.16380/j.kcxb.2022.10.008

• 研究论文 • 上一篇    下一篇

稻纵卷叶螟幼虫驯化产生的热适应能力的继代效应

李明珠, 刘向东*   

  1. (南京农业大学植物保护学院昆虫学系, 南京 210095)
  • 出版日期:2022-10-20 发布日期:2022-11-27

Transgenerational effect of heat adaptation induced by heat acclimation in larvae of the rice leaf folder, Cnaphalocrocis medinalis (Lepidoptera: Crambidae)

LI Ming-Zhu, LIU Xiang-Dong*   

  1.  (Department of Entomology, College of Plant Protection, Nanjing Agricultural University, Nanjing 210095, China)
  • Online:2022-10-20 Published:2022-11-27

摘要: 摘要: 【目的】在全球不断变暖背景下,昆虫受到热胁迫的频率不断增加。短期内反复受到热胁迫会使昆虫产生热适应性,但是昆虫热驯化所产生的耐热能力的传代效应还不完全清楚。稻纵卷叶螟Cnaphalocrocis medinalis是水稻上的重要害虫,对其幼虫在特定温度下进行几代热锻炼可提高其对高温的适应能力。本研究旨在摸清稻纵卷叶螟热适应的传代能力,为在全球变暖形势下以温度因子预测其种群发展趋势提供指导。【方法】将实验室内分别经39℃和41℃连续锻炼30代建立的稻纵卷叶螟热锻炼品系HA39和HA41以及非锻炼品系HA27的1-5龄期幼虫在不同温度(36℃和41℃)下进行不同时长(1~144 h)的暴露处理,调查幼虫的存活率,确定热锻炼品系幼虫的耐热能力;采用两品系间杂交实验测定HA39和HA27各交配组合的繁殖力及后代3龄幼虫的耐热能力;对HA39停止高温锻炼,并测定停止锻炼2代后3龄幼虫的耐热能力。【结果】稻纵卷叶螟3龄幼虫经历多代次短期热锻炼不仅可提高该龄幼虫的高温适应力,而且可提高其他龄期幼虫对特定高温的耐受能力,表现为HA39和HA41在36或41℃下处理特定时长的存活率显著高于HA27。锻炼高温的不同,幼虫获得的热耐受能力也有差异。39℃下锻炼可提高4龄幼虫在36℃下暴露2和4 d以及5龄幼虫在41℃下暴露5和6 h时的存活率,但41℃下锻炼则不可。HA39和HA27的自交及杂交后代的繁殖力之间均无显著差异,杂交后代3龄幼虫在41℃下处理5和6 h时的存活率与HA39自交后代的相当,并且显著高于HA27自交后代的,幼虫通过热锻炼获得的耐热能力可从亲本遗传给后代。停止热锻炼2代后,在39℃下处理4 h时HA39 3龄幼虫的存活率显著高于HA27的,但39℃下其余处理时间以及36和41℃下处理1~7 h HA39 3龄幼虫的存活率均与HA27的无显著差异,表明幼虫热锻炼产生的耐热能力在停止锻炼后2代仍可部分保持。【结论】稻纵卷叶螟幼虫的热适应能力具有继代效应。经过长期的气候变暖适应后,稻纵卷叶螟种群的热适应能力很可能在不断增强,从而夏季高温对其种群的抑制作用减弱,其种群暴发频率增加。

关键词:  稻纵卷叶螟, 热适应, 高温, 存活率, 传代效应

Abstract: Abstract: 【Aim】 The frequency of insects encountering heat stress is increasing under the situation of global warming. Insects will generate heat acclimation when repeatedly impacted by short-term high temperature. However, the transgenerational effect of heat adaptation induced by acclimation is still not very clear. The rice leaf folder, Cnaphalocrocis medinalis, is a serious pest of rice, and its larvae can adapt to high temperature when they are acclimated to a specific temperature for several generations. This study aims to illustrate the transgenerational heat adaptation of C. medinalis, so as to provide the guidance for the forecast of its population trends under global warming using the index of temperature. 【Methods】 The 1st-5th instar larvae of the heat-acclimated strains HA39 and HA41 of C. medinalis after 30 generations of acclimation to 39℃ and 41℃, respectively, and the unacclimated strain HA27 established in the laboratory were exposed to different high temperatures (36℃ and 41℃) for different time (1-144 h), and then their survival rates were examined and the heat tolerance was assessed. The hybridization experiments between HA39 and HA27 were performed to examine the fecundity of various mating combinations and the heat tolerance of the 3rd instar larvae of their offspring. The heat tolerance of the 3rd instar larvae from HA39 was also measured after stopping heat acclimation for two generations. 【Results】 The short-term heat exposure of C. medinalis at the 3rd instar larval stage for multiple generations increased the heat tolerance of not only the 3rd instar larvae but also the other instar larvae to a specific heat stress. When exposed to 36℃ and 41℃ for a specific duration, the survival rates of larvae of HA39 and HA41 were significantly higher than that of HA27. The heat tolerance of larvae was dependent on the acclimation temperature. Acclimation to 39℃ increased the survival rates of the 4th instar larvae exposed to 36℃ for 2 and 4 d and the 5th instar larvae exposed to 41℃ for 5 and 6 h, but the acclimation to 41℃ could not. The fecundity among the self-bred and crossbred offspring of HA39 and HA27 was not significantly different. The heat tolerance of the crossbred offspring showed that the survival rates of the 3rd instar larvae of the crossbred offspring exposed to 41℃ for 5 and 6 h were comparable to that of the self-bred offspring of HA39, and significantly higher than that of the self-bred offspring of HA27. The heat tolerance acquired by acclimation could be transferred into the offspring from parents. When the heat acclimation to 39℃ had stopped for two generations, the survival rate of the 3rd instar larvae of HA39 exposed to 39℃ for 4 h was significantly higher than that of HA27, but those of HA39 exposed to 39℃ for other time and exposed to 36℃ and 41℃ for 1-7 h showed no significant difference from those of HA27,indicating that the tolerant ability of the heatacclimated strain to high temperature can still be partially maintained in two generations after stopping heat acclimation. 【Conclusion】 The heat adaptation of C. medinalis larvae has the transgenerational effect. The ability of C. medinalis populations to adapt to high temperature is likely increasing under longterm global warming, and therefore the negative effect of high temperature in summer upon its populations will be weaker, and consequently its population outbreaks will be frequent.

Key words:  Cnaphalocrocis medinalis, heat acclimation, high temperature, survival rate, transgenerational effect