Andreadis S S, Vryzas Z, Papadopoulou-Mourkidou E, Savopoulou-Soultani M
Department of Plant Protection, Aristotle University of Thessaloniki, Thessaloniki, Greece.
Cryo Letters. 2011 Jul-Aug;32(4):297-307.
Sesamia nonagrioides Lefébvre (Lepidoptera: Noctuidae) is considered one of the most destructive pests of corn in the Mediterranean region. The purpose of the present study was to investigate some aspects of the cold tolerance of non-diapausing and diapausing laboratory reared larvae of S. nonagrioides, as well as of field-collected larvae, taking into consideration various parameters, such as supercooling ability, mean lethal temperature and accumulation of cryoprotectant substances, in relation to diapause. Our results provide evidence that S. nonagrioides has limited cold tolerance as it displays a low ability of supercooling. This is strongly supported by the fact that mortality of the individuals occurred after extended exposure to subzero temperatures, equivalent or slightly lower to their mean supercooling point. However, lethal temperatures of diapausing larvae were significantly lower in relation to that of non-diapausing larvae, indicating the existence of a direct link between diapause and cold tolerance. Regarding the role of cryoprotectant substances, accumulation of glycerol seems to be closely related to diapause, in contrast to accumulation of trehalose, which is more related to exposure to low temperatures slightly higher than 0 degree C. Finally, non-diapausing larvae of different instars displayed a similar ability of supercooling and tolerance to low temperatures as well as accumulation of cryoprotectant substances. The ecological significance of our findings on cold tolerance of this species is being discussed with particular reference to the microclimate observed in northern Greece.
地中海粉螟（Sesamia nonagrioides Lefébvre，鳞翅目：夜蛾科）被认为是地中海地区对玉米危害最大的害虫之一。本研究的目的是调查实验室饲养的非滞育和滞育地中海粉螟幼虫以及田间采集幼虫的耐寒性的某些方面，同时考虑各种参数，如过冷却能力、平均致死温度和抗冻保护物质的积累与滞育的关系。我们的结果表明，地中海粉螟的耐寒性有限，因为它的过冷却能力较低。这一点得到有力支持，即个体在长时间暴露于低于其平均过冷却点的零下温度后死亡。然而，滞育幼虫的致死温度明显低于非滞育幼虫，表明滞育与耐寒性之间存在直接联系。关于抗冻保护物质的作用，甘油的积累似乎与滞育密切相关，而海藻糖的积累则更多地与暴露于略高于0摄氏度的低温有关。最后，不同龄期的非滞育幼虫表现出相似的过冷却能力、对低温的耐受性以及抗冻保护物质的积累。我们对该物种耐寒性的研究结果的生态意义将结合希腊北部观察到的小气候进行特别讨论。
