Effect of Crowding and Plant Height on Insect Abundance

This experiment was done at the grasslands at york university, Toronto Canada over the course of two days between the hours of 2:30 PM and 5:30 PM. On day one the weather was approximately 13 Degrees C and mostly sunny and day 2 was partly cloudy and approximately 10 Degrees C. In this experiment 40 plastic bowls (each day totaling 80 bowls), all of the same colour were placed randomly within the grasslands and filled at least one quarter the way full with soapy water. After all bowls were placed a 1m by 1m quadrat was placed around each bowl and the crowding of living or dead plant matter within the quadrat was estimated from 0-4 (0 meaning no plant biomass 4 meaning no ground could be seen through the plants). Afterwards, the average plant height was estimated with the use of a transect. The tallest and shortest plants were measured, the estimation was made based upon how much area the talest and shortest plants took up within the quadrat and the measurement was recorded in inches. after all measurements had been taken, the bowls were left for 2 hours. When the 2 hours were up the bowls were collected and the number of insects caught in the bowls were counted and recorded. This experiment was conducted to see how the abundance of insects were effected by plant height and plant crowding. This data can be useful to see which, crowding or height, effects insect abundance more. It is also interesting to note that even though the temperatures for both days of the experiment were close, only 3 degree difference, there were significantly fewer insects on the second day of testing.