两种切梢小蠹危害云南松的时空生态位

Temporal and spatial niches of two sympatric Tomicus species pests of Pinus yunnanensis Faranch.

【目的】云南切梢小蠹Tomicus yunnanensis Kirkendall&Faccoli和横坑切梢小蠹Tomicus minor(Hartig)是中国云南地区两种危害松属Pinus L.植物的钻蛀性害虫,常在云南松Pinus yunnanensis Faranch.上共同危害,通过蛀梢和蛀干为害造成树木衰弱死亡,生态破坏,带来经济损失。【方法】通过样地调查和树木解析,对两种小蠹在"梢转干"及"干转梢"时期的时间和空间生态位进行了研究。【结果】"梢转干"时期之后,横坑切梢小蠹主要分布在主干中下部,云南切梢小蠹分布在主干中上部;侧枝上主要分布着云南切梢小蠹,而横坑切梢小蠹数量很少;5月中旬进入"干转梢"阶段,两种小蠹同时进入羽化期,云南切梢小蠹在6月1日左右到达羽化高峰期,横坑切梢小蠹则比其晚10 d左右到达羽化高峰期;两种小蠹成虫转梢危害后随机分布。两种小蠹的时间和空间生态位宽度均较大,发生期较长,在云南松上分布范围较广。两种小蠹空间生态位重叠较小,在云南松上的分布趋于分离,对空间资源的需求具有较大差异;而时间生态位重叠较大,在云南松的生长季节能同时危害,且发生期较一致,危害期长。【结论】两种小蠹在空间生态位上的种间竞争强度较小,而在时间生态位上的竞争较大。通过研究比较两种切梢小蠹时间及空间生态位的特性及差异,为遥感监测云南松林的生物灾害提供了支撑依据。

[Objectives] Tomicus yunnanensis Kirkendall ＆ Faccoli and Tomicus minor Hartig are two wood boring pests that endanger pine species of the genus Pinus L. in southwest China. These species are often both found on Pinus yunnanensis Faranch where they feed on the shoots and bore into the trunk, causing tree death, ecological damage and economic loss. [Methods] We investigated the temporal and spatial niches of these two species during the ＂branch to trunk＂ and ＂trunk to branch＂ periods by conducting sampling at different field sites, stem dissection and analysis. [Results] After the ＂branch to trunk＂ period, T. minor is mainly distributed in the mid to bottom sections of trunks, whereas T. yunnanensis is mainly found on the upper trunk. T. yunnanensis was mainly found in branches but T. minor was predominantly found in trunks. The ＂trunk to branch＂ period began in mid-May, at which time the two species begin to emerge simultaneously. The peak of T. yunnanensis emergence occurred around June 1st and the peak of T. minor emergence was about ten days later. The two species were randomly distributed during the ＂trunk to branch＂ period. The temporal and spatial niche widths of the two species were broad, indicating that both species are active for a relatively long period and can therefore inflict damage on P. yunnanensis over a relatively long period of time. Spatial niche overlap between the two species was small, indicating that their distribution on P. yunnanensis differed, reducing interspecific competition. However, the temporal niche overlap of the two species was large, which indicates that they both damage to P. yunnanensis during the growing season, and they have almost the same emergence period. [Conclusion] Although the temporal overlap between the two species was high, their spatial overlap within individual P. yunnanensis trees was low. These results clarify the spatial and temporal niches of these two Tomicus species and provide important information to support remote sensing monitoring of outbreaks of these pests in P. yunnanensis forests.