Comparative Anatomy of the Insect Tracheal System Part 1: Introduction, Apterygotes, Paleoptera, Polyneoptera

ABSTRACT A broad comparative study of insect respiratory morphology is presented. Tracheae, epidermal invaginations extending into the body in branching networks of tubes, supply tissues with direct access to air for gas exchange. While previous tracheal studies focused on a handful of taxa and lacked in consistency, here a unified system of tracheal nomenclature is established using visualizations from micro-CT scanning of representatives from apterygotes, Paleoptera, and Polyneoptera, totaling 29 species, 29 genera, and 26 families in 13 insect orders. Three-dimensional visualizations of named tracheal branches establish robust assessments of homology and provide a framework for further studies across class Insecta. Patterns in respiratory architecture are presented along with a discussion of future investigations into phylogenetic and physiological questions.