Oligophagy and absence of food‐aversion learning in tobacco hornworms, Manduca sexta

Temporary illness can be induced in tobacco hornworms, Manduca sexta , by feeding them on Atropa belladonna or Nerium oleander that have been sprayed with insecticides, or by feeding them on unsprayed Petunia. Behavioural preference tests showed that recovered larvae did not avoid the plants that induced illness. Thus, these larvae did not exhibit food‐aversion learning of the kind demonstrated in phytophagous terrestrial slugs and in vertebrates. The ecological significance of these results is discussed.