Insect Abundance in Grasslands and Woodlands at York University

The abundance of insects attracted to bright colours in different habitats was measured in the Saywell Woodlot and the Grassland east of Stong Pond at York University on September 30, 2014 between 2:30 PM and 5:30 PM. At this time, the temperature averaged 18ᵒC and the sky was dark due to a small amount of precipitation earlier in the day. A 100 foot transect was laid westward from the east edge of the Grassland and 3 sets of bowls were placed 5 meters apart along the transect, starting 10m west of the east edge. Each set of bowls consisted of 3 different coloured bowls (1 yellow, 1 blue, and 1 white) that were each half full with soapy water. Each bowl was directly adjacent to the other bowls of the set, forming a triangular formation. After placing the bowls in the Grassland, a 100 foot transect was laid northward from the north edge of the main path in the Woodlot. 3 sets of 3 bowls (1 yellow, 1 blue, and 1 white) half filled with soapy water were placed 5 meters apart along this transect, starting 10m north of the main path’s north edge. Each set of bowls was given 90 minutes before being examined for insects. Each set of bowls was treated as a single replicate, and counted for total abundance of insects, different RTUs, and abundance of Diptera, Hymenoptera, Orthoptera, and Hemiptera. Each independent insect was counted if it was submerged in the soapy water (dead or living) and had distinguishable features visible to the naked human eye. The experimenter determined the order of each individual insect through visual inspection and use of a dichotomous key.

2014年9月30日14:30至17:30期间，研究人员于约克大学（York University）的塞韦尔林地（Saywell Woodlot）与斯通塘东侧草地，开展了不同生境中趋亮色昆虫丰度的测定实验。当日前期出现少量降水，致使天空阴沉，实验时段平均气温为18℃。在该草地东侧边缘向西布设一条长100英尺的样带（transect），自东侧边缘以西10米处起始，沿样带每隔5米放置3组诱集碗；每组诱集碗包含黄色、蓝色、白色各1只，每碗盛有半量肥皂水，且组内各碗彼此紧邻，呈三角形排布。在塞韦尔林地主步道北侧边缘向北布设一条长100英尺的样带，自主步道北侧边缘以北10米处起始，沿样带每隔5米放置3组诱集碗，每组同样包含黄、蓝、白三色碗各1只，每碗盛有半量肥皂水。每组诱集碗放置90分钟后，开展昆虫采集与计数工作。每组诱集碗视为一个生物学重复单元，分别统计昆虫总丰度、不同可操作分类单元（RTUs）的数量，以及双翅目（Diptera）、膜翅目（Hymenoptera）、直翅目（Orthoptera）与半翅目（Hemiptera）的昆虫丰度。凡浸没于肥皂水中（无论存活与否）、且肉眼可辨识形态特征的独立昆虫个体，均纳入统计范畴。研究人员通过目视观察并借助二歧检索表（dichotomous key），对每只昆虫进行分类鉴定。