林间花斑花绒寄甲幼虫种群动态及空间分布格局

花绒寄甲Dastarcus helophoroides Fairmaire以幼虫寄生松褐天牛Monochamus alternatus等天牛类害虫，掌握其幼虫时空动态和空间分布格局，有助于制定花绒寄甲的生物防治利用策略。通过对江西马尾松林花绒寄甲幼虫种群数量的调查，应用聚集度指标和回归分析等，对林间花绒寄甲幼虫种群动态、水平分布和垂直分布进行了研究。结果表明，林间花绒寄甲幼虫种群动态呈现极明显的波动性，全年数量动态有2个高峰期，其中主高峰期是4月份，占全年幼虫总数量的30%左右，是幼虫的主要寄生期，次高峰期是8月份。花绒寄甲幼虫水平空间分布为聚集分布，分布的基本成分是个体群，聚集的原因可能是花绒寄甲自身习性或与寄主天牛、环境因素共同作用所致。不同时间段，花绒寄甲幼虫的垂直分布情况不同，3-7月，花绒寄甲幼虫主要分布在枯死木的中上部，其中上段幼虫数占总数的50%以上，而在8-12月，花绒寄甲幼虫主要分布在枯死木的中段，占总数的50%左右。另外，调查显示，花绒寄甲幼虫寄生数量在释放过该天敌的松林要远高于未释放过的松林，特别是在马尾松纯林，其幼虫种群数量更高，这说明通过人工释放（江西在3月释放成虫），能增加林间天敌花绒寄甲种群数量、降低松褐天牛种群数量，有助于松材线虫病的控制。花绒寄甲幼虫种群时空、水平、垂直三维空间分布结果可为该天敌的保护、人工释放和有效利用提供科学依据。

Population dynamics and spatial distribution pattern of Dastarcus helophoroides larvae in forest

Dastarcus helophoroides Fairmaire parasitizes longicorn pests such as Monochamus alternatus with larvae. Mastering the temporal and spatial dynamics and spatial distribution pattern of its larvae is helpful to formulate the biological control and utilization strategy of D. helophoroides. The population dynamics, horizontal distribution and vertical distribution of D. helophoroides larvae in Pinus massoniana Forests in Jiangxi Province were studied by using aggregation index and regression analysis. The results showed that the population dynamics of D. helophoroides larvae in the forest showed very obvious fluctuation. There were two peaks in the annual quantitative dynamics. The main peak was in April, accounting for about 30% of the total number of larvae in the whole year, and it was the main parasitic period of the larvae. And the second peak was in August. The horizontal spatial distribution of D. helophoroides larvae was aggregation distribution, and the basic component of distribution was individual group. The aggregation may be caused by its own habits or the interaction with host and environmental factors. In different time periods of the year, the vertical distribution of the larvae was different. From March to July, the larvae were mainly distributed in the middle and upper parts of the dead wood, of which the upper part accounts for more than 50% of the total. From August to December, the larvae were mainly distributed in the middle part of the dead wood, accounting for about 50% of the total. In addition, the survey showed that the parasitic number of D. helophoroides larvae in the pine forest that had released the natural enemy was much higher than that in the pine forest that had not released the natural enemy. Especially in the pure forest of P. massoniana, the larval population was higher, which showed that the number of D. helophoroides species can be increased and the population of M. alternatus can be reduced through artificial release (Jiangxi released adults in March). It was helpful to control Bursaphelenchus xylophilus. The results that spatial-temporal, horizontal and vertical three-dimensional spatial distribution of D. helophoroides larvae can provide a scientific basis for the protection, artificial release and effective utilization of the natural enemy.