Lasius niger ants discriminate aphids based on their cuticular hydrocarbons

Mutualistic interactions between organisms depend on the ability of each partner to recognize the other. In ant–aphid mutualisms, ants have to recognize whether an aphid colony is worth tending. Many aphid species can live in mutualistic associations with ants (trophobiosis), whereas others are never tended and are frequently preyed upon by ants. Since aphids often produce low amounts of honeydew when not tended by ants, the ants should be able to recognize potential trophobionts based on signals other than honeydew. Conversely, aphids should signal if they are potential trophobionts. We investigated whether ants recognize potential trophobiont aphids based on their behaviour, morphological…