Khodayari S, Colinet H, Moharramipour S, Renault D
Department of Entomology, Faculty of Agriculture, Tarbiat Modares University, P.O. Box 14115-336, Tehran, Iran.
Environ Entomol. 2013 Dec;42(6):1415-21. doi: 10.1603/EN13086. Epub 2013 Nov 18.
The twospotted spider mite Tetranychus urticae Koch (Acari: Tetranychidae) is an important agricultural pest. Population dynamics and pest outbreaks highly depend on the overwintering success of the mite specimens; therefore, it is necessary to assess winter survival dynamics of this pest. Seasonal changes in supercooling point (SCP) and acute cold tolerance (2-h exposure at -5, -10, -15, -20, -23, or -25°C) were assessed in field-collected females during the winter in 2010-2011 in Iran. The SCP values varied from a minimum of -30.5°C (January 2011) to a maximum of -12.6°C (April 2011). Significant differences were recorded in the SCP distribution patterns between autumn- and winter-sampled females, depicting the acquisition of cold hardiness over the winter. The mean ambient air temperature was the lowest in January (4°C), when the females showed the highest supercooling ability. Correlated patterns between monthly temperatures and acute cold tolerance also were found. At -20°C, the survival of the mites was very low (10%) when they were sampled in October 2010; whereas it was high (97.5%) in January 2011, before decreasing to 5% in April 2011. The present data show that T. urticae females are chill tolerant and capable of adjusting their cold tolerance over the winter season. Acute cold tolerance (-15 and -20°C) and SCP represent valuable metrics that can be used for predicting the seasonal changes of the cold hardiness of T. urticae females.
二斑叶螨Tetranychus urticae Koch（蜱螨亚纲：叶螨科）是一种重要的农业害虫。种群动态和害虫爆发高度依赖于螨类样本的越冬成功率；因此，有必要评估这种害虫的冬季存活动态。2010 - 2011年冬季，对在伊朗田间采集的雌性二斑叶螨进行了过冷却点（SCP）和急性耐寒性（在-5、-10、-15、-20、-23或-25°C下暴露2小时）的季节性变化评估。SCP值最低为-30.5°C（2011年1月），最高为-12.6°C（2011年4月）。秋季和冬季采样的雌性二斑叶螨在SCP分布模式上存在显著差异，表明其在冬季获得了耐寒性。1月份平均环境气温最低（4°C），此时雌性二斑叶螨表现出最高的过冷却能力。还发现了月温度与急性耐寒性之间的相关模式。在-20°C时，2010年10月采样的螨类存活率非常低（10%）；而在2011年1月存活率很高（97.5%），到2011年4月降至5%。目前的数据表明，二斑叶螨雌性具有耐寒性，并且能够在冬季调节其耐寒能力。急性耐寒性（-15和-20°C）和SCP是可用于预测二斑叶螨雌性耐寒性季节性变化的有价值指标。
