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【目的】二点委夜蛾Athetis lepigone(Mschler)是我国夏玉米苗期的新害虫,随着耕作制度的改变,二点委夜蛾的发生危害区域和面积逐渐扩大。本研究探讨二点委夜蛾的抗寒能力,为揭示抗寒机理提供理论基础。【方法】分别在越冬期的3个不同阶段,即越冬初期(2012年11月7日)、越冬期(2012年1月20日)和越冬末期(2013年3月5日),对二点委夜蛾老熟幼虫的体重、过冷却点(supercooling point,SCP)、结冰点(freezing point,FP)、含水量、脂肪和糖原含量进行测定。【结果】过冷却点在这3个时期有显著差异,最低值(-23.16±0.38℃)出现在1月份,最高值(-16.24±1.24℃)出现在越冬初期,结冰点变化趋势与过冷却点一致。通过定量检测发现,虫体鲜重与过冷却点无相关性(r=0.17,P=0.12);脂肪含量在越冬初期含量最高,而在越冬末期最低;糖原含量在越冬期含量最低;自由水的含量随着过冷却能力升高而降低,随其降低而升高,而结合水含量恰好相反。【结论】二点委夜蛾的抗寒性在越冬期不同阶段出现明显的变化,即随着冬季低温的到来,其抗寒能力逐渐增强,冬季过后又随气温的回升,其抗寒力逐渐减弱。
【Objective】 Athetis lepigone (Mschler) is a new pest of summer maize seedling stage in China. With the change of tillage system, the area and area harbored by Spodoptera litura increased gradually. In this study, we investigated the cold resistance of the second instar Spodoptera litura and provided a theoretical basis for revealing the mechanism of cold resistance. 【Method】 During the early wintering period (November 7, 2012), overwintering period (January 20, 2012) and late wintering period (March 5, 2013) The body weight, supercooling point (SCP), freezing point (FP), water content, fat and glycogen content of the larvae of larvae were measured. 【Result】 The results showed that the subcooling point was significantly different in these three periods. The lowest value (-23.16 ± 0.38 ℃) appeared in January and the highest value (-16.24 ± 1.24 ℃) appeared in the early winter. The trend of freezing point The same cooling point. The results showed that there was no correlation between fresh weight and supercooling point (r = 0.17, P = 0.12). The content of fat was the highest in the early winter and the lowest in the late winter; the content of glycogen was the lowest during the winter; Water content decreases with increasing supercooling capacity, increasing as it decreases, and the combined water content is just the opposite. 【Conclusion】 The cold resistance of the second instar larvae showed obvious changes in different stages of overwintering period, that is, with the arrival of cold in winter, the ability of cold resistance gradually increased, and gradually increased with the temperature rise after winter Weakened.