新疆同域亚洲玉米螟和欧洲玉米螟对温度的适应性差异

Difference in the temperature adaptability between the sympatric Ostrinia furnacalis and O.nubilalis(Lepidoptera:Crambidae)in Xinjiang,northwest China

【目的】通过明确当前世界唯一一处亚洲玉米螟Ostrinia furnacalis和欧洲玉米螟O.nubilalis同域混生区内伴有激烈种间竞争关系的两个近缘种玉米螟主要生物学特性对温度的适应性差异水平,揭示新疆混生区欧洲玉米螟种群被亚洲玉米螟快速取代的生物学驱动机制。【方法】在15, 20, 25, 30和35℃下测定比较了新疆同域环境下分离获得的两个近缘种亚洲玉米螟和欧洲玉米螟种群的卵历期、卵块孵化率、单块卵粒孵化率和卵块死亡率及20, 25, 30和35℃下成虫寿命、产卵前期、产卵期、单雌产卵量、幼虫和蛹历期、幼虫重和蛹重等参数。【结果】欧洲玉米螟在15, 20, 25和35℃下的卵块死亡率均显著高于亚洲玉米螟的,在20, 25, 30和35℃下的平均单块卵粒孵化率则显著低于亚洲玉米螟的;随温度的升高,欧洲玉米螟卵块孵化能力显著降低,至35℃时,卵块死亡率最大(73.42%±2.28%),平均单块卵粒孵化率最低(48.46%±2.64%),而亚洲玉米螟卵块死亡率和平均单块卵粒孵化率分别为41.88%±4.33%和67.99%±2.52%。在20, 25, 30和35℃下同域亚洲玉米螟和欧洲玉米螟间的产卵前期、雌成虫寿命、雄成虫寿命和产卵期均无显著差异,但欧洲玉米螟的单雌产卵块数、单雌所产单个卵块平均卵粒数以及平均单雌产卵量等主要繁殖力指标均显著低于亚洲玉米螟的。较低温度(20和25℃)下,欧洲玉米螟相比于亚洲玉米螟具有较大的1-4龄幼虫重,但随着温度的升高,至30和35℃时欧洲玉米螟2和3龄幼虫重显著小于亚洲玉米螟的,20, 25和35℃下欧洲玉米螟各幼虫历期和蛹历期与亚洲玉米螟的无显著差异。【结论】亚洲玉米螟较欧洲玉米螟具有更好的温度适应能力,尤其是高温(30和35℃)下,亚洲玉米螟卵块存活率更高,孵化能力更好,繁殖力和体重相比更大,竞争力相对更强。

【Aim】By clarifying the difference in the temperature adaptability of the main biological characters between two closely related species of corn borers,the Asian corn borer(Ostrinia furnacalis)and European corn borer(O.nubilalis),living in the only one sympatric region in the world and accompanied by fierce interspecific competition,this study aims to reveal the biological driving mechanism of the rapid replacement of O.nubilalis population by O.furnacalis in the sympatric region in Xinjiang,Northwest China.【Methods】At 15,20,25,30 and 35℃,the egg duration,egg mass hatching rates,egg hatching rates per egg mass and mortalities of egg masses of the O.furnacalis and O.nubilalis populations isolated from the same region in Xinjiang,and at 20,25,30 and 35℃,their adult longevity,pre-oviposition period,oviposition period,numbers of eggs laid per female,larval and pupal duration,larval and pupal weight etc.were measured and compared.【Results】The results showed that the mortalities of egg masses of O.nubilalis were significantly higher than those of O.furnacalis at 15,20,25 and 35℃,and the average egg hatching rates per egg mass of O.nubilalis were significantly lower than those of O.furnacalis at 20,25,30 and 35℃.Furthermore,the hatching ability of egg masses of O.nubilalis decreased significantly with the increase of temperature,until the temperature increased to 35℃,the mortality of egg masses was the highest(73.42%±2.28%)and the average egg hatching rate per egg mass was the lowest(48.46%±2.64%),while those of O.furnacalis were 41.88%±4.33%and 67.99%±2.52%,respectively.At the same temperature,there was no significant difference in the pre-oviposition period,female adult longevity,male adult longevity and oviposition period between sympatric O.furnacalis and O.nubilalis.However,the main fecundity indexes of O.nubilalis,such as the number of egg masses laid per female,average number of eggs per egg mass laid by a single female and average number of eggs laid per female,were significantly lower than those of O.furnacalis.Compared with O.furnacalis,O.nubilalis had significantly heavier 1st-4th instar larval weight at the low temperature of 20℃.However,at higher temperatures(30 and 35℃),the 2nd and 3rd instar larval weight of O.nubilalis was significantly lighter than that of O.furnacalis and the duration of various instar larvale and pupal duration of O.nubilalis showed no significant difference from those of O.furnacalis.【Conclusion】Compared with O.nubilalis,O.furnacalis has better temperature adaptability.Especially at high temperatures(30 and 35℃),O.furnacalis has higher survival rate of egg masses,better hatching ability,higher fecundity and heavier body weight,showing stronger competitiveness.