Red spider mite

A species of plant-feeding mite that is generally considered a pest. It is the most widely known member of the family Tetranychidae or spider mites. Its genome was fully sequenced in 2011, and was the first genome sequence from any chelicerate.
Tetranychus urticae is extremely small, barely visible with the naked eye as reddish or greenish spots on leaves and stems; the adult females measure about 0.4 mm long The red spider mite, which can be seen in greenhouses and tropical and temperate zones, spins a fine web on and under leaves.