Cultural flies: conformist social learning in fruit flies predicts long-lasting mate-choice traditions

Despite theoretical justification for the evolution of animal culture, there is still scant empirical evidence for it beyond mammals and birds, and we still know little about the process of cultural inheritance. Here, we propose a mechanism-driven definition of animal culture and test it in the fruit fly. We found that fruit flies have five cognitive capacities that enable them to transmit mating preferences culturally across generations, potentially fostering persistent traditions (the main marker of culture) in mating preference. A transmission chain experiment validates a model of the emergence of local traditions indicating that such social transmission may lead initially neutral traits to become adaptive, hence strongly selecting for copying and conformity, a situation that, although suggested decades ago, still had little empirical support.