气候变暖对油松毛虫幼虫越冬及上下树发生期的影响

温度是影响害虫生长发育最重要的因素之一,为了解气温的变化趋势以及在此背景下油松毛虫Dendrolimus tabulaeformis Tsai et Liu幼虫越冬及上下树的动态变化,本文根据辽宁省建平县1988—2009年期间油松毛虫上下树发生期资料和气象资料,分析了建平县气温年变化趋势和油松毛虫上下树发生期年变化趋势,探讨了发生期与气温之间的相关性,结果表明:近22年(1988—2009)建平县气侯变暖的趋势显著,线性倾向估计分析发现年均气温、年均最低气温和年均最高气温均呈现出上升趋势,气候倾向率分别达0.50、0.59和0.36℃/10年,四季中春季气温的升幅最大,夏秋两季次之,冬季最低。在此气候变暖背景下油松毛虫幼虫上下树及越冬发生着一定的变化趋势,其中:下树总体呈现出提前发生、提前结束、下树历期缩短的变化趋势;翌年幼虫上树期则呈现出延迟发生、提前结束、上树历期缩短的变化趋势;整个越冬期长度则呈现出延长的变化趋势。相关性分析认为气候变暖对油松毛虫的下树活动具有直接影响,主要表现为下树结束期随气候变暖而显著提前,在不考虑其它因素的影响下,9—10月均气温上升1℃则下树结束期会提前约2 d,而幼虫越冬及上树发生期表现为并不受气候变暖的直接影响。研究结果为有效控制油松毛虫危害提供了理论依据。

Influence of climate warming on overwintering behaviour of the larva of Dendrolimus tabulaeformis

Temperature is one of the most important factors affecting a pest＇ s growth and development. We looked for a correlation between temperature change trends in Jianping county of Liaoning Province and the periods of occurrence of three behaviours of the larva of Dendrolimus tabulaeformis Tsai et Liu; climbing up the host tree, descending the host tree and overwintering. We compared recent temperature trends based on climate data from 1988--2009 with changes in timing of the selected behaviours of the larva of D. tabulaeformis based on observations recorded over the same period. The climate record indicates a significant warming trend in Jianping county of Liaoning Province during the 22 years from 1988 to 2009. Assuming a linear trend for temperature change we show that annual mean temperature, annum mean maximum temperature and annual mean minimum temperature all exhibit escalating trends, estimated at 0. 50℃/10 years, 0.59℃/ 10 years and 0. 36℃/10 years, respectively. Seasonally, spring shows the highest escalation in temperature, summer and autumn show medium escalation and winter the lowest. Under climate warming, the periods of occurrence of climbing up and down the host tree and overwintering displayed changing trends. The behaviour of descending the host tree tends to begin and end earlier and the duration of this behaviour decreases. The occurrence of climbing up the host tree tends to begin later and end earlier so that the duration of this behaviour decreases. The duration of overwintering tends toincrease. Analysis shows that climate warming has a direct influence on the occurrence of climbing down behaviour, with the cessation of this behaviour tending to advance significantly with temperature escalation. Excluding other factors, the end of the climbing down period would advance 2 days with 1℃ of temperature increased. However, the periods of overwintering and climbing up the host tree appear not to be directly correlated with climate warming. This research could provide a theoretical basis for practical control of this pest.