Tolerance of Winged and Wingless Insects to Variation in Temperature and Plant Density of a Grassland Habitat at York University: How Species Abundance Varies over Time and Space

This experiment took place in the Grassland east of Stong Pond at York University between October 14 and October 22, 2014. Between 2:30PM and 5:30PM on October 14, 15, 21 and 22, three 100 foot transects were laid down in different areas. Two transects were laid westward from the east edge of the Grassland, where one of the two transects was 20 meters North of the other. The third transect was laid southward on the field directly east of the Grassland. For one of the two westward transects, experimenters used scissors to cut a random number of plants (excluding grass) from the bottom of their stems if the bottom of their stem was within 0.5 meters of the outer edge of the transect. To estimate the abundance of winged and wingless insects in a certain area, a quadrat would be centred along each transect every 5 meters. This meant that the distance between the centres of two consecutive quadrats would measure 5 meters. For each quadrat that was placed, experimenters estimated plant density within the inner edges of each quadrat. Following this, a pan trap would be placed directly adjacent to a pitfall trap in the centre of each quadrat that was placed. A pan trap consisted of a white plastic bowl that was half full with soapy water and rested on the surface of the ground. A pitfall trap consisted of a white Styrofoam cup buried and anchored into the ground with a white Styrofoam bowl suspended on top. A total of six quadrats were placed for each transect on a single day. At the end of placing all 18 pairs of traps in a day, the outdoor temperature was recorded. 24 hours after placing the traps, experimenters returned to measure the abundance of winged insects and the abundance of wingless insects in each pair of a pan trap and pitfall trap. These abundances were later taken to calculate the total insect abundance, proportion of winged insects, and the proportion of wingless insects for each replicate.