The energy cost and efficiency of burrowing in the sandy-beach whelk Bullia digitalis (Dillwyn) (Nassariidae)

Abstract

The oxygen consumption of Bullia digitalis (Dillwyn) at 15°C has been measured in the laboratory under conditions which gave rise to repeated digging cycles, and compared with oxygen uptake while the same animals were stationary. The energy cost of burrowing is calculated to be about 5 × 10 −4 Joules (2.1 × 10 −3cal) per digging cycle in a whelk whose dry tissue weight is 750 mg. The overall efficiency of the burrowing process is ≈ 6%, in contrast to the 20% efficiency which has generally been assumed for locomotory activities.