Application of a high-throughput respirometry technique for assessing respiratory metabolism of terrestrial and aquatic invertebrates.

Abstract

Respiratory metabolism is one of the key ecological traits of organisms. As such, it is studied by ecologists from a wide range of disciplines, from macroecological studies to evolutionary biology, with the global changes context making the need for its understanding more pressing. Unfortunately, properly measuring respiration is a time- and cost-intensive endeavor, and gathering large datasets can be prohibitive due to the difficulty of measuring it. Here, we describe a fluorescence-based high-throughput closed-system respirometry technique for terrestrial and aquatic invertebrates, able to measure respiration for up to 240 channels in parallel in vials of 2 or 4 ml. We used a setup originally designed to continuously measure oxygen in laboratory cell cultures in liquid medium to measure arthropod respiration. Through a series of experiments, we demonstrate the reliability of the system to measure respiration of arthropods. Even very small arthropods were able to be measured, although Drosophila had to be measured in groups of 2 to 4. Further, the system's modularity makes it particularly fit for assessing full thermal performance curves of respiratory metabolism in a small amount of time. We provide helpful guidelines and R scripts to make use of this system to create thermal performance curves of insect metabolism.