Aphids (Aphidoidea) belong to the plant lice with 3000 known species, of which about 850 live in Central Europe in many colours and sizes. All of them feed on plant sap. Many of them are specialised on very specific plants - for example, probably the most dangerous species in viticulture - the phylloxera, which exclusively attacks the vine. They also change their appearance in the course of the year, the life cycle is very complex. The winged aphids are responsible for dispersal, the next, unwinged generations are relatively stationary and form dense colonies very quickly. As plant suckers, the animals are equipped with a stinging proboscis. The aphids feed by piercing and then sucking out juices from leaves and also roots. As a defensive reaction of the plants, galls (growths) form on leaves or roots.