Analyzing the Effect of Body Mass on the Metabolic Rate of Ectotherms

Endothermic research has consistently correlated an increase in body mass with a decrease in metabolic rate; however, there is limited research addressing this relationship within the field of ectotherms due to their environmentally dependent physiology. This research project is focused on determining the relationship between body mass and metabolic rate within ectotherms through analyzing the carbon dioxide production of Madagascar hissing cockroaches ( Gromphadorhina portentosa ) and house crickets ( Acheta domestica). It is hypothesized that within ectotherms, the metabolic rate will decrease as the body mass increases because the smaller surface area to volume ratio of larger ectotherms will decrease the rate of heat loss. This research question is being tested by massing three randomly selected groups for each species and averaging their carbon dioxide production in three experimental trials of five minute intervals. The experimental results indicate an inverse relationship between body mass and metabolic rate, which supports this hypothesized relationship between ectothermic species.