Mouthparts

The stylets are set tightly close to each other throughout the length of the rostrum. They slide to and fro against each other so delimiting two specific channels: the salivary and food canals. The stylets enable the aphids to penetrate the plants, reaching the phloem and the criblo-vascular bundles that transport the sap they have produced.

In general the stylets are thrust into the tissue taking an intercellular path, although sometimes they do penetrate inside the cells. As the insect pushes its stylets further into the plant, it injects saliva which dries out in the zone around them to form a setal sheath, a stiff covering of hair like a scabbard enabling the aphid to operate its stylets, take them out again if disturbed, or make a fresh attack on the plant, ...