Minimum Cost of Transport and Ventilatory Patterns in Three African Beetles

Minimum cost of pedestrian transport (Mrun) was determined by treadmill running and flow-through oxygen respirometry in three species of flightless beetles, Psammodes striatus, Pachysoma hippocrates, and Anthia fabricii. Mrun was 1.67, 4.76, and 2.15 ml O₂/(g · km) (where g · km = ml O₂/[kg · m]), respectively, in these three species, which have typical masses of 2.9, 3.1, and 2.2 g, respectively. Extrapolations of vertebrate-based regressions of Mrun on mass predict similar values of Mrun given these masses. When combined with those for mammals and birds <1,000 g, all published Mrun data on insects are related to mass by the equation Mrun = 0.530M−0.325, where M is in kg and Mrun is in ml O₂/(g · km). All species ventilated discontinuously while at rest.