The Relationship between Environmental Temperature and Metabolic Rate in Endotherms and Ectotherms

Abstract

We are exploring the differences in metabolic rates in endotherms and ectotherms as the environmental temperature changes.  The key impact of our research is to help pet companies to know the temperature at which the metabolic rate is the lowest without being critical so the pet will eat the least amount of food and can be shipped most efficiently.  We are attempting to figure out whether mice, Mus musculus, or crickets, Gryllus assimilis, have a lower metabolic rate at a lower temperature in order to see at what temperature the mice and crickets would eat less food.  We predict that as the temperature decreases, the metabolic rate of the ectotherm will decrease while the metabolic rate of the endotherm will increase because ectotherms rely on environmental temperature to thermoregulate while endotherms rely on cellular respiration to thermoregulate.  Other studies have focused primarily on different sizes of either endotherms or ectotherms, while we are focusing on both endotherms and ectotherms and how temperature affects each of them.  We are measuring the oxygen consumed per gram of the mice and crickets at room temperature and 10°C to compare their metabolic rate.  We will place the mice and crickets into a respiration chamber to measure their oxygen consumption at room temperature and 10°C over a period of 5 minutes to measure their metabolic rate.  The average metabolic rate for the mice at room temperature was 0.8180 O₂/sec/g.  The average metabolic rate for the mice at 10°C was 0.7013 O₂/g/sec.  The average metabolic rate for the crickets at room temperature was 2.0518 O₂/sec/g. The average metabolic rate for the crickets at 10°C was 1.4303 O₂/sec/g.