Lung ventilation during treadmill locomotion in a semi‐aquatic turtle, Trachemys scripta

Abstract

It is reasonable to presume that locomotion should have a mechanical effect on breathing in turtles. The turtle shell is rigid, and when the limbs protract and retract, air in the lungs should be displaced. This expectation was met in a previous study of the green sea turtle, Chelonia mydas; breathing completely ceased during terrestrial locomotion (Jackson and Prange, 1979. J Comp Physiol 134:315-319). In contrast, another study found no direct effect of locomotion on ventilation in the terrestrial box turtle, Terrapene carolina (Landberg et al., 2003. J Exp Biol 206:3391-3404). In this study we measured lung ventilation during treadmill locomotion in a semi-aquatic turtle, the red-eared slider, Trachemys scripta. Sliders breathed almost continuously during locomotion and during brief pauses between locomotor bouts. Tidal volume was relatively small (approximately 1 mL) during locomotion and approximately doubled during pauses. Minute ventilation was, however, not significantly smaller during locomotion because breath frequency was higher than that during the pauses. We found no consistent evidence for phase coupling between breathing and locomotion indicating that sliders do not use locomotor movements to drive breathing. We also found no evidence for a buccal-pump mechanism. Sliders, like box turtles, appear to use abdominal musculature to breathe during locomotion. Thus, locomotion affects lung ventilation differently in the three turtle species studied to date: the terrestrial Te. carolina shows no measurable effect of locomotion on ventilation; the semi-aquatic Tr. scripta breathes with smaller tidal volumes during locomotion; and the highly aquatic C. mydas stops breathing completely during terrestrial locomotion.

Evolution of Air Breathing: Oxygen Homeostasis and the Transitions from Water to Land and Sky

“…At rest, limb movements aid inspiration and expiration (247,249,525). During terrestrial locomotion, ventilation is affected differently in different species: The marine Chelonia mydas stops moving to breathe (347), the semiaquatic T. scripta breathes with a smaller tidal volume while moving, (406), and the terrestrial Terrapene carolina is not affected at all (405). …”

Shoulder girdle rotation, forelimb movement, and the influence of carapace shape on locomotion inTestudo hermanni(Testudinidae)

“…The derived morphological characters of turtles have fundamental consequences for several biological functions, particularly with regards to locomotion and respiration (Friant, 1961;Gans and Hughes, 1967;Zug, 1971;Walker, 1973;Rivera et al, 2006;Landberg et al, 2003Landberg et al, , 2009. Variation in size and shape of the shell within the Testudines has been demonstrated to significantly influence the volume of the lungs, the shape of the shoulder girdle and the excursion range of the limbs (Zug, 1971;Jayes and Alexander, 1980;Depecker et al, 2006a).…”

Diving strategy of Amyda cartilaginea (Boddaert, 1770) and Cuora amboinensis (Daudin, 1802) in the perspective of respiratory structure and function

“…There are many studies about respiratory system related to the diving strategy of some turtle species. They are dominated by studies on sea turtle [8][9][10][11][12][13], while the studies on softshells turtle and terrapene only on turtles' species from America and other regions except South East Asia [14][15][16].…”