Isometric spiracular scaling in scarab beetles-implications for diffusive and advective oxygen transport.

ABSTRACT: The scaling of respiratory structures has been hypothesized to be a major driving factor in the evolution of many aspects of animal physiology. Here, we provide the first assessment of the scaling of the spiracles in insects using 10 scarab beetle species differing 180× in mass, including some of the most massive extant insect species. Using X-ray microtomography, we measured the cross-sectional area and depth of all eight spiracles, enabling the calculation of their diffusive and advective capacities. Each of these metrics scaled with geometric isometry. Because diffusive capacities scale with lower slopes than metabolic rates, the largest beetles measured require 10-fold higher P_O2 gradients across the spiracles to sustain metabolism by diffusion compared to the smalles

SUBMITTER: Wagner JM 

PROVIDER: S-EPMC9522208 | biostudies-literature | 2022 Sep

REPOSITORIES: biostudies-literature