Energetics of Concertina Locomotion in Bipes biporus (Reptilia: Amphisbaenia)

Abstract

Rates of oxygen consumption and whole-body lactate concentrations were measured in adult Bipes biporus (x SVL = 171.6 mm; x mass = 5.19 g; x body temperature = 25 C) during: 1) minimal activity (standard metabolic rate); 2) 30 min of voluntary, concertina locomotion; and 3) 2 min of intense, forced exercise. Mean rate of oxygen consumption during concertina locomotion (Vo2 conc = 0.214 ml 02/g'h) was significantly greater than mean standard metabolic rate (Vo2 stan = 0.035 ml 02/g h), and was 36% of that during forced exercise (Vo2 exer = 0.601 ml O2/g h). Mean lactate concentration during concertina locomotion (0.115 mg lactate/g body mass) did not differ significantly from that during minimal activity (0.129 mg/g). However, forced exercise resulted in a significant increase in mean lactate content (0.442 mg/g). Mean locomotor speed during constant, voluntary concertina locomotion was 0.1 km/h. The total cost of transport (=TCT) for B. biporus at 0.1 km/h and 25 C was 2.1-2.2 ml O2/ g km and is estimated to be, at similar speed and temperature, approximately as energetically efficient as lateral undulation in the snake, Thamnophis sirtalis (TCT = 2.2 ml O2/gkm), and from 58-67% as expensive as quadrupedal lomotion in two species of lizards (Cnemidophorus murinus: TCT = 3.2 ml 02/g km; Dipsosaurus dorsalis: TCT = 3.7 ml 02/g km).