The success of a habitat specialist biological control agent in the face of disturbance

A field study was conducted in alfalfa fields in the Arlington Agricultural Research Station, Dane County, Wisconsin, USA.
Three fields were studied. Each field was divided into three sections and in each section a one of three treatments was implemented:
1.       Control – harvesting normally, once a month (medium disturbance)
2.       Insecticide – harvesting as in the control + implementing insecticide spray (permethrin insecticide Pounce 32 EC (8 oz/ac)) immediately after harvest (high disturbance)
3.       Strips – harvesting in strips (low disturbance)
In each field and each section insects were collected during the summer of 2001 (exact dates are in the files). Insects were collected with sweep nets, the number of sweeps changed in according to the number of aphids in the field, and is given in the files for each sample. Mummies of Apidius ervi were collected by visual searches of three minutes.

本研究于美国威斯康星州戴恩县阿灵顿农业研究站的苜蓿田中开展野外实地试验。
共纳入3块试验田，每块田划分为3个小区，每个小区接受下述3种处理中的一种：
1. 对照组：每月常规收割1次，属于中等干扰处理
2. 杀虫剂处理组：收割模式与对照组一致，于收割后立即喷施氯菊酯类杀虫剂Pounce 32 EC（用量8盎司/英亩），属于高干扰处理
3. 条带收割处理组：采用条带式收割方式，属于低干扰处理

2001年夏季，于每块试验田及各小区内采集昆虫样本，具体采样日期详见数据集文件。
昆虫采集采用扫网（sweep nets）法，扫网次数根据田间蚜虫（aphids）数量调整，各样本对应的扫网次数已记录于数据集文件中。
此外，通过为期3分钟的目视搜索，采集蚜茧蜂（Apidius ervi）的僵蚜样本。