J. Oberman, CCA, 11/25/00



Effects of crowding crickets on cellular respiration


We examined the effects of overcrowding of animals and its effects on stress.

Since one common response to overcrowding in people is increased stress we hypothesized that overcrowding would also increase stress in crickets as well.   A typical response to overcrowding in people is also increased heart rates and blood pressure.  Therefore we predicted that – If overcrowding increases stress in crickets, we would see a higher rate of respiration per gram of cricket in an overcrowded chamber compared to a chamber that was not overcrowded.  In the our first treatment, we had 10 crickets in a closed area and the slope of their CO2 level was 35.27 ppm/min. and a respiration rate of 30.07 ppm/min/gram. Then we increased the number of crickets to 50 to test if the crowding of the crickets affected their respiration rate. We found the slope of the CO2 level to be 412.09 ppm/min. and the respiration rate to be 65.09 ppm/min/gram. Evaluating our results led us to fail to reject our hypothesis and conclude that the increased density of the crickets does increase the respiration rate.   Our study and interpretation has several potential flaws.  First we had a small sample size and we did not replicate our experiment.  Second, in the container with 50 crickets we noticed an increase in activity levels.  Battiglea, Perchocs, and Young in another student project showed that activity levels may increase respiration rates.