TY - JOUR
T1 - Water storage compromises walking endurance in an active forager
T2 - Evidence of a trade-off between osmoregulation and locomotor performance
AU - Davis, Jon R.
AU - Denardo, Dale
N1 - Funding Information:
Acknowledgments This manuscript beneWted from reviews by the DeNardo laboratory, the Physiology Reading Group at ASU, G. Wals-berg, B. Sullivan, D. Beck, and two anonymous reviewers. This research was funded by the School of Life Sciences at ASU, a National Science Foundation Graduate Research Fellowship to JRD, and private donations to the ASU Foundation. Research was conducted in accordance with Arizona State University’s Institutional Animal Care and Use Committee policies (IACUC protocol No. 05-792R) as required legally by the USA and the experiments comply with the “Principles of animal care”, publication No. 86-23, revised 1985 of the National Institute of Health.
PY - 2008/8
Y1 - 2008/8
N2 - Trade-offs between locomotor performance and load-carrying in animals are well-established and often result from requisite life processes including reproduction and feeding. Osmoregulation, another necessary process, may involve storage of fluid in the urinary bladder of some species. The purpose of this study was to determine whether storage of urine in the urinary bladder reduces walking endurance in an actively foraging lizard. The results of our paired-design study indicate that the volume of fluid stored in the urinary bladder (36.5 ± 1.6 ml) contributed a significant load (9.2% of body mass) to the lizards. This load resulted in a disproportionate 24.5 ± 2.8% decrement in walking endurance. Specifically, Gila monsters walked at a fixed pace for a significantly shorter duration when the urinary bladder contained fluid (26 ± 2.0 min) compared to when the bladder was empty (34.3 ± 2.3 min). Since fluid stored in the bladder contributes to osmoregulation in this species, our results indicate the presence of a trade-off between osmoregulation and endurance in Gila monsters. Bearing other loads (e.g., a clutch or meal) influences the evolution of life-history traits and foraging strategy; thus the negative effect of fluid storage on endurance may also have evolutionary implications.
AB - Trade-offs between locomotor performance and load-carrying in animals are well-established and often result from requisite life processes including reproduction and feeding. Osmoregulation, another necessary process, may involve storage of fluid in the urinary bladder of some species. The purpose of this study was to determine whether storage of urine in the urinary bladder reduces walking endurance in an actively foraging lizard. The results of our paired-design study indicate that the volume of fluid stored in the urinary bladder (36.5 ± 1.6 ml) contributed a significant load (9.2% of body mass) to the lizards. This load resulted in a disproportionate 24.5 ± 2.8% decrement in walking endurance. Specifically, Gila monsters walked at a fixed pace for a significantly shorter duration when the urinary bladder contained fluid (26 ± 2.0 min) compared to when the bladder was empty (34.3 ± 2.3 min). Since fluid stored in the bladder contributes to osmoregulation in this species, our results indicate the presence of a trade-off between osmoregulation and endurance in Gila monsters. Bearing other loads (e.g., a clutch or meal) influences the evolution of life-history traits and foraging strategy; thus the negative effect of fluid storage on endurance may also have evolutionary implications.
KW - Foraging
KW - Heloderma
KW - Physiological reservoir
KW - Water balance
UR - http://www.scopus.com/inward/record.url?scp=48749088295&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=48749088295&partnerID=8YFLogxK
U2 - 10.1007/s00359-008-0342-2
DO - 10.1007/s00359-008-0342-2
M3 - Article
C2 - 18478235
AN - SCOPUS:48749088295
SN - 0340-7594
VL - 194
SP - 713
EP - 718
JO - Journal of Comparative Physiology A: Neuroethology, Sensory, Neural, and Behavioral Physiology
JF - Journal of Comparative Physiology A: Neuroethology, Sensory, Neural, and Behavioral Physiology
IS - 8
ER -