Locusts show rapid individual learning but no social learning about food

Socially influenced learning is important because it can drive the spread of novel behaviours among individuals within and between generations. While work on a few vertebrates suggests the conditions favouring the use of social over individual learning, we know little about the evolution of social learning. As a part of an ongoing examination of the evolutionary roots of social learning in insects, we tested for social learning in locusts, Locusta migratoria. Locusts showed rapid individual learning, preferring a diet they ate for a single meal of only 20 min over another diet of equal nutritional quality. Locusts, however, did not show stronger preference for novel food that they had previously consumed while in the presence of a conspecific experienced with that food. Furthermore, focal locusts did not learn about novel food from (1) experienced conspecifics that were observable through a screen, (2) interactions with conspecifics that had previously fed on and gave off odours from novel food and (3) cannibalizing conspecifics that had recently fed on novel food. Whereas our results extend previous work indicating excellent individual learning in locusts, they provide no evidence for socially influenced learning in a species that, in its gregarious form, has the opportunity for social learning and could benefit from such an ability.