竹裂爪螨自然种群消长及空间格局研究

Dyanmics and Spatial Distribution Pattern of Natural Population of Schizotetranychus bambusae Reck(Acari:Tetranychidae)

本文对毛竹害螨优势种竹裂爪螨Schizotetranychus bambusae Reck自然种群在主要发生季节的消长情况进行了调查.结果表明,竹裂爪螨在林间发生的高峰期为5～6月份.发生的严重度与林份条件有密切关系,在土壤瘠薄、林相较差的林区发生重;海拔较高、人为干扰度大的林区的发生重且高峰有所延后.竹裂爪螨在林间不同年龄竹株上存在转移危害,即4～5月,3年生竹上(当年不换叶)的有螨叶率与平均每叶螨量大于2年生竹;5月下旬以后,2年生竹换叶完成、新竹开始上林,竹裂爪螨逐渐转移到新叶上为害,使得在1年生竹、2年生竹上的发生量逐渐超过3年生竹上的发生量.通过对5、6月发生高峰期的空间格局研究表明,竹裂爪螨在毛竹林间呈聚集分布,且密度越高,聚集度越大.利用Iwao的m*-m回归分析表明,竹裂爪螨是以个体群的方式存在.从空间格局的动态规律上看,5月份的聚集度大于6月份的聚集度,其中5、6月份的m*-m回归式分别为:m*=2.265+2.342 m(R=0.853,5月份)、研*=1.612+2.171m(R=0.952,6月份).

The seasonal dynamics of Schizotetranychus bambusae Reck was investigated in Changning Bamboo Area, Yibing, Sichuan, P. R. China from April to October 1998. The results showed that an obvious peak occurred between May and June was identical with the sensitive developmental period of the moso bamboo, Phyllostachys pubescens. The occurrence degree was closely related tt the geographical location and habitat. At Area I (630 m elevations with poor bamboo appearance due to infertile soil), leaf percentage with mite and average mites per leaf were 67. 64% and 6. 35 in May, 58. 06 % and 5. 02 in June, respectively. At Area III (900 m elevations with poor bamboo forest appearance as a result of man's disturbance), leaf percentage with mite and average mites per leaf were 46. 68% and 4. 29 in May, 75. 31% and 7. 40 in June, respectively. But at Area II (755 m elevations with high botanical richness and good bamboo growth. ), leaf percentage with mite and average mites per leaf in May were 29. 72% and 2. 33, respectively. Average mil es per leaf of S. bambusae were also affected bamboo age. Mites per leaf in three-year-old bamboo were more than in two-year-old bamboo before mid May. Controversially, mites per leaf in 2-year-old and 1-year-old bamboo were more than in 3-year-old bamboo after early June. The K Value of negative binomial distribution, index of clumping (I), mean crowding (m* ), and mean of patchiness (m*/m) indicated that the spatial pattern of S. bambusae was of the aggregation distribution. The basic component was clumps and aggregation increased with population density. The equations of m* -m were m* =2. 265 + 2. 342 m in May, and m* =1. 612 + 2. 171 m in June, respectively.