Fig. 8

Ixodes ricinus, scanning electron micrographs of convective tracheae from fasting (left image column, figures a, c, e) and fully engorged (right image column, figures b, d, f) females. a Low power micrograph of a trachea of a fasting tick. The distance between the taenidiae is minimal. b Low power micrograph of a trachea of a fully engorged tick. Same magnification as in (a). The distance between the taenidiae has greatly extended (black arrow). c Trachea of a fasting tick at intermediate magnification. d Trachea of a fully engorged tick at intermediate magnification. The distance between taenidia has more than tripled, indicating the expansion of the tracheae associated with the volume increase of the body. e High power magnification of a trachea of a fasting tick. In this position the internal surface of the tracheae is densely covered with microstructures. f High power magnification of a trachea of a fully engorged tick. Same magnification as in (e). Double headed arrows indicate distance between two neighboring taenidia in fasting (left) and digesting (right) ticks