Figure 3.

Quantitative changes of the tracheal system during metamorphosis. (A) Differences in diameter of major longitudinal tracheae across different type of modules and developmental stages. Data are mean ± SD. Measurements were taken directly at the midpoint between neighbouring spiracles, except tracheae heading anteriorly from ts1, where diameter was measured just before the entrance of dorsal and ventral longitudinal trunks to head. Different letters indicate significant differences across particular stadium (Tukey's HSD test, P < 0.05). (B) Modifications of spiracles and tracheal vestibules. Relative size of tracheal vestibules presented as the ratio between volume of given tracheal vestibule and total body volume. (C) Relative distance of spiracles of same body segment presented as the ratio between distance between given pair of spiracles divided by maximum width head capsule. (D) Number of tracheal ramifications corresponds to number of tracheae originating directly in given tracheal vestibule. (E) Relative distance along longitudinal body axis (length) between spiracles corresponds to ratio of distance between neighbouring spiracles and total body length. Data are mean ± SD. as1–as8, abdominal spiracles 1–8; ts1, mesothoracic spiracle; ts2, metathoracic spiracle; dlt, dorsal longitudinal trunk; vlt, ventral longitudinal trunk.