Oxygen concentration affects upper thermal tolerance in a terrestrial vertebrate

详细信息    查看全文

• 作者：Tanner K. Shea ^{tkshea@calpoly.edu" class="auth_mail" title="E-mail the corresponding author} ; P. Mason DuBois ^{pmdubois@calpoly.edu" class="auth_mail" title="E-mail the corresponding author} ; Natalie M. Claunch ^{nclaunch@calpoly.edu" class="auth_mail" title="E-mail the corresponding author} ; Nicolette E. Murphey ^{nicolettemurphey@gmail.com" class="auth_mail" title="E-mail the corresponding author} ; Kiley A. Rucker ^{karucker@calpoly.edu" class="auth_mail" title="E-mail the corresponding author} ; Robert A. Brewster ^{rabrewst@calpoly.edu" class="auth_mail" title="E-mail the corresponding author} ; Emily N. Taylor ; ^{etaylor@calpoly.edu" class="auth_mail" title="E-mail the corresponding author}
• 关键词：Gaping ; Panting ; Loss of righting response ; Critical thermal maximum ; Thermal tolerance ; Oxygen ; Lizard ; Sceloporus occidentalis
• 刊名：Comparative Biochemistry and Physiology - Part A: Molecular & Integrative Physiology
• 出版年：2016
• 出版时间：September 2016
• 年：2016
• 卷：199
• 期：Complete
• 页码：87-94
• 全文大小：626 K

文摘

We tested the oxygen limitation hypothesis, which states that animals decline in performance and reach the upper limits of their thermal tolerance when the metabolic demand for oxygen at high temperatures exceeds the circulatory system's ability to supply adequate oxygen, in air-breathing lizards exposed to air with different oxygen concentrations. Lizards exposed to hypoxic air (6% O₂) gaped, panted, and lost their righting response at significantly lower temperatures than lizards exposed to normoxic (21% O₂) or hyperoxic (35% O₂) air. A greater proportion of lizards in the hyperoxic treatment were able to withstand body temperatures above 44 °C than in the normoxic treatment. We also found that female lizards had a higher panting threshold than male lizards, while sex had no effect on gaping threshold and loss of righting response. Body size affected the temperature at which lizards lost the righting response, with larger lizards losing the response at lower temperatures than smaller lizards when exposed to hypoxic conditions. These data suggest that oxygen limitation plays a mechanistic role in the thermal tolerance of lizards.