Meeting Abstract
Oxygen availability and temperature are two of the most important environmental factors affecting all of animal life. However, the two are not independent of each other and may exert similar selective pressures on animals. Animals should be most susceptible to high temperatures and oxygen variation during times of high performance and during early developmental stages. Through a series of experiments on lizards and insects, we have begun to examine the interactive effect of oxygen and temperature on terrestrial animals exposed to hypoxia, high temperatures, and a combination of both during flight and embryonic development in the egg. The results of these experiments have been mixed in their support for the concept of an effect of oxygen during periods of thermal stress. We have shown that oxygen does limit thermal tolerance during embryonic development in lizards. However, while both hypoxia and high temperature have a detrimental effect on insect flight, there was no interactive effect between temperature and acute oxygen exposure or rearing oxygen. Additionally, while it has been shown before that extreme hypoxia does limit thermal tolerance in lizards, we have shown that ecologically relevant oxygen levels have no effect on voluntary maximum temperature. Lastly, we have been looking for a genetic correlation between flight performance during hypoxia and flight performance during high temperatures. Based on these experiments, there is limited support for the concept of oxygen limitation on thermal tolerance in terrestrial animals, however, more experiments under ecologically relevant conditions and behaviorally relevant activities need to be done.
