Behaviour towards an unpreferred colour: can green flowers attract foraging hawkmoths?

Nave hawkmoths (Manduca sexta) learn from a single trial to approach and attempt to feed from an artificial flower of an innately unpreferred green colour even when a distractor flower with a preferred yellow colour is present. In some of the animals, the choice of the innately unpreferred colour during free-flight testing persists for several days despite not being rewarded and eventually leads to starvation. The results show that moths exhibit a very strong flower constancy that is not limited to the colours of nectar flowers.