The defence against predators or parasitoids is a very important aspect for aphids.Many aphid species rely on ants for their defence, establishing ant-aphid societies, whilst others defend themselves. Previous studies indicated that some aphid species are able to defend their colonies by synchronous movements of the hind legs. In addi-tion, two species of aphids using this defence mechanism also displayed chemical de-fence. The two studied species were Aphis nerii (mostly found on Nerium oleander) and Uroleucon hypocheridis (found on hairy cat`s ear, Hypochoeris radicata). On the one hand the aphids use rapid movement of their hind legs to physically repel intruders, on the other hand they secrete substances which prevent the intruder from predation.This chemical defence via the cornicle secretions is especially effective against cocci-nellid larvae foraging close to the colony. If the secreted substance hits the target, it hardens within seconds, gluing the larvae. However, physical defence is more effecti-ve against smaller predators such as the parasitoid wasp Aphidius colemani, but may function also against ants. Individuals within one colony benefit from collective defence because they all are most likely clone-mates, reproduced copies of one individual.Here I describe behavioural observations on 2 species of aphids in their interaction with different predators, parasitoids and ants.