小蛀果斑螟幼虫空间格局及抽样技术研究

Spatial pattern and sampling technique of Assara exiguella (Caradja) Larvae in chestnut orchards

对7个板栗园小蛀果斑螟幼虫空间格局调查结果表明:小蛀果斑螟幼虫在板栗园中的分布是遵循负二项分布的聚集分布,其中Iwao的m*-m回归模型为m*=2.2825+1.0471m,Taylor幂模型为lg(v)=0.4467+1.1287lg(m)。对各聚集度指标的分析结果显示:在板栗园中的小蛀果斑螟幼虫彼此之间互相吸引,分布的基本成分是个体群,个体群为聚集分布,且在任何密度下都是聚集的,聚集强度随着密度的升高而增大。导致小蛀果斑螟幼虫在板栗园中呈聚集分布的原因是由该虫本身的习性和环境共同造成的。小蛀果斑螟幼虫虫口密度调查的最适理论抽样数公式为n=t2/D2.(3.2825/m+0.0471)。

The spatial distribution patterns of Assara exiguella （Caradja） larvae in different chestnut orchards were surveyed and analysized. The results showed that the larvae were in aggregation distribution fit for negative binomial pattern. Its Iwao＇s m^＊-m model was m^＊=2.2825＋1.0471m and Taylor＇s power model lg （v）= 0.4467＋1.12871g （m）. By analysing the aggregation index, the larva was attractive by each other in chestnut orchards and its basic component of distribution was colony which were in aggregation distribution even at low population density and more aggressive with population density increasing. The aggreggation distribution of the larvae was due to its life habit and environmental factors. In addition, the optimum theoretical sampling number of the larvae could be obtained from the formula n=t^2/D^2· （3.2825/m＋0.0471）.