Metabolic Rates of Gromphadorhina portentosa (Madagascar Hissing Cockroaches) Based Off Of Body Mass

Abstract

In this lab we tested the metabolic rates of different sized Gromphadorhina portentosa (Madagascar Hissing cockroaches) in order to determine if body size affects the metabolic rate of different sized organisms. The metabolic rate of an organism is defined as the chemical processes that are being carried out inside to sustain life (Bear, 2016). Metabolism rates correspond to whether an organism is an ectotherm or an endotherm, as well as their surface area to volume ratio (Clarke, 2002). In order to test the metabolic rate we measured the difference of  CO2 levels between various sizes of Madagascar Hissing cockroaches. We accomplished this experiment by placing a single cockroach in a small respirator chamber and used the CO2 probes to measure their output, which could determine their metabolic rate. The carbon dioxide output was then used to determine if the smaller the mass of the cockroach, the greater the metabolic rate would be. We discovered that the largest cockroach had the highest metabolic rate instead of the smallest. We concluded this because of the results from the metabolic rates we found. We did not allow a set amount of CO2 to build up in the chamber, so that the initial CO2 readings for each cockroach would be relatively the same. Another factor may have led to these results was the stress that the cockroaches were under. Our hypothesis was not proven correct through our experiment; however our results are similar to those found from crickets in the study conducted by Gin, 2019 (Gin, 2019).