Abstract

Herreid II, C.F., R.J. Full and D.A. Prawel. 1981. Energetics of cockroach locomotion. J. exp. Bio. 94: 189-202.

Cockroaches, Gromphadorhina portentosa, were run at different speeds for 20 min on a miniature treadmill enclosed in a lucite respirometer while oxygen consumption V(O2) was continuously monitored. The data collected. on these 5 g insects are remarkably similar to those obtained on vertebrates. V(O2) rises rapidly with the onset of exercise; the t(1/2) on-response was about 1 min with steady-state reached within 4 min at the fastest speed, 0.12 km/h. Recovery was rapid; the t(1/2) off-response was 4-6 min, with total recovery achieved in less than 1 h. The tracheal system appears to be a highly efficient mode of O2 conductance in contrast to the crustacean method of delivery involving gills and circulation. V(O2) (ml 02/g*h) at steady-state running varies directly with velocity (V). The regression equation at 24 °C is V(O2)=0.45+4.92V. The Y-intercent, at zero velocity, is 2.4 times the actual resting V(02) rate of 0.19 ml O2/g*h. Temperature does not change the slope of the regression line but shifts it up or down in accordance with a simple Q(10) effect. Incline running produces no changes compared to level running. The minimum cost of transport, the lowest V(02) necessary to transport a given mass a specific distance, is high in cockroaches (4.92ml O2/g*km) and comparable to that expected for a small quadrupedal or bipedal pedestrian vertebrate.