The effects of temperature on oxygen consumption in the lizard Pseudocordylus melanotus from Suikerbosrand Nature Reserve

Abstract

In reptiles, metabolic rate (MR) is affected by many different factors, including temperature, sex, body size and digestive state. Standard MR was measured for the lizard Pseudocordylus melanotus over a range of temperatures (20, 22, 25, 30 and 32°C). I measured oxygen consumption using a closed respirometry system and tested for the effects of body mass and temperature. Body mass and total MR were significantly related at 20, 22, 25 and 32°C. Body mass and mass-specific MR were significantly related at 20°C. MR increases significantly with increasing temperature for both total and mass-specific MR. Both mass exponents and temperature quotients (Q₁₀) were similar to those reported for other lizards and snakes. Field measures of body temperature were used to estimate energy expenditure for a standard 40 g lizard. Daily energy expenditures during summer and winter were 3074.32 J/day and 1537.46 J/day, respectively. A 40 g lizard, therefore, requires the equivalent of two to three mealworms per day to cover the costs of maintenance metabolism. Any additional energy assimilated can be allocated to growth, reproduction and storage.