Abstract

The insect respiratory system is a network of air-filled tubes permeating the animal body, supplying oxygen for metabolic activity and removing waste carbon dioxide. The majority of gas exchange occurs in the finest regions of the tracheal system, the terminal cells. These cells have a unique and highly specialized tree-like structure with long thin branches, reminiscent of neuronal arbors. While many aspects of the terminal cell are understood on a molecular level, including the mechanisms that guide branch extension and lumen formation, the macroscopic network features that allow for proper oxygen distribution remain mysterious. We use the terminal cell as a model system for several developmental problems, utilizing an imaging data set that fully maps the structure of hundreds of individual cells. The benefits of our investigations are insights into properties of mammalian capillary networks, which have different structural features and delivery mechanisms from terminal cells but are believed to be guided by similar developmental principles. Understanding the salient features that govern the structure of these biological networks is essential to designing synthetic vasculature, a major step in the manufacture of artificial organs.