PMC

Mechanism of felting shrinkage of wool.

Clistopyga sp. in action. With its ovipositor, it searches for the host, stings, clings to and paralyses it, lays an egg and finally seals any opening in the silken spider nest by using it as a minute felting needle. (Online version in colour.)

A felting needle and the ovipositor of Clistopyga sp. with a similar function. (a) The tip of a felting needle with procurved notches that entangle fibres during the downstroke. Scale bar, 1 mm. (b) Stacked image of the apically upcurved ovipositor. Scale bar, 0.2 mm. (c) SEM image of the ovipositor tip in lateral view showing six recurved apical teeth of the left lower valve, which are diminishing in size towards the apex of the ovipositor. When used as a felting needle, the tips of the movable lower valves need to be held beyond the tip of the upper valve in order to expose the teeth. Because the teeth are recurved, the ovipositor entangles spider silk only during the upstroke. (d) The same tip in ventral view showing how the teeth can be enclosed by the broader upper valve when not in use. Uv, upper valve; Lvl, left lower valve; Lvr, right lower valve. (Online version in colour.)

Different symptoms observed on the sampled symptomatic weed species. Symptoms were identified in different groups as follows: black necrosis (blN), brown felting (brF), brown necrosis (brN), chlorosis (C), orange pustule (oP), pink necrosis (pN), powdery mildew (pM), rust (R), and white pustule (wP).