Energetics of Pedestrian Locomotion in Adult Male Blowflies, Protophormia terraenovae (Diptera: Calliphoridae)

Abstract

We describe the metabolic cost of voluntary pedestrian locomotion in adult male blowflies, Protophormia terraenovae (Diptera: Calliphoridae) from measurements made in a running tube. The minimum cost of transport (MCOT) based on interindividual comparisons for male blowflies is 254 J kg⁻¹ m⁻¹ (SE = 41). This value was similar to the MCOT based on intraindividual comparisons (208 J kg⁻¹ m⁻¹, SE = 72). These estimates are very near the predicted MCOT for limbed arthropods of the same size, despite the fact that, unlike insects that rely exclusively on pedestrian locomotion, blowflies must carry a substantial mass of flight muscle while walking. The cost of transport for walking adult flies is almost an order of magnitude lower than the cost of crawling by larval flies. We also used ANCOVA to estimate the MCOT for individual flies tested at three temperatures: 28°, 32°, and 37° C. There was no detectable temperature-by-individual interaction or temperature effect on the MCOT, and the MCOT estimated by this procedure (319 J kg⁻¹ m⁻¹, SE = 83) was statistically indistinguishable from the estimates based on intra- and interindividual comparisons at a single temperature.