Laboratory of Agrozoology, Department of Crop Protection, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, 9000 Ghent, Belgium.
J Insect Physiol. 2010 Apr;56(4):438-44. doi: 10.1016/j.jinsphys.2009.11.019. Epub 2009 Dec 9.
As an essential aspect of its invasive character in Europe, this study examined the cold hardiness of the harlequin ladybird Harmonia axyridis. This was done for field-collected populations in Belgium overwintering either in an unheated indoor or an outdoor hibernaculum. The supercooling point, lower lethal temperature and lower lethal time at 0 and -5 degrees C were determined. Possible seasonal changes were taken into account by monitoring the populations during each winter month. The supercooling point and lower lethal temperature remained relatively constant for the overwintering populations in the outdoor hibernaculum, ranging from -17.5 to -16.5 degrees C and -17.1 to -16.3 degrees C, respectively. In contrast, the supercooling point and lower lethal temperature of the population overwintering indoors clearly increased as the winter progressed, from -18.5 to -13.2 degrees C and -16.7 to -14.1 degrees C, respectively. A proportion of the individuals overwintering indoors could thus encounter problems surviving the winter due to premature activation at times when food is not available. The lower lethal time of field populations at 0 and -5 degrees C varied from 18 to 24 weeks and from 12 to 22 weeks, respectively. Morph type and sex had no influence on the cold hardiness of the overwintering adults. In addition, all cold tolerance parameters differed greatly between the laboratory population and field populations, implying that cold tolerance research based solely on laboratory populations may not be representative of field situations. We conclude from this study that the strong cold hardiness of H. axyridis in Europe may enable the species to establish in large parts of the continent.
作为其在欧洲入侵特性的一个重要方面，本研究检查了欧洲猩红红瓢虫（Harmonia axyridis）的耐寒性。这是通过对在比利时未加热的室内或室外冬眠场所越冬的野外采集种群进行的。确定了过冷却点、致死低温和在 0 和-5°C 时的致死时间。通过在每个冬季月份监测种群，考虑了可能的季节性变化。在室外冬眠场所越冬的种群的过冷却点和致死低温相对稳定，范围分别为-17.5 至-16.5°C 和-17.1 至-16.3°C。相比之下，在室内越冬的种群的过冷却点和致死低温随着冬季的进展而明显增加，范围分别为-18.5 至-13.2°C 和-16.7 至-14.1°C。由于在没有食物的情况下过早激活，因此一部分在室内越冬的个体可能会在冬季遇到生存问题。在 0 和-5°C 时，野外种群的致死时间从 18 周到 24 周不等，从 12 周到 22 周不等。形态类型和性别对越冬成虫的耐寒性没有影响。此外，所有耐寒性参数在实验室种群和野外种群之间差异很大，这意味着仅基于实验室种群的耐寒性研究可能不能代表野外情况。我们从这项研究中得出结论，欧洲猩红红瓢虫的强耐寒性可能使其能够在欧洲大陆的大部分地区建立。
