The lady fruit flies that inhabit your banana bowl may find green-colored mates with curly wings simply irresistible -- conforming to the "local dating culture" of generations of female flies before them, a new study finds. It reveals how female fruit flies get their cues for choosing a mate based on the partners they see other female fruit flies choose. The study's results suggest that culture, once thought to be exclusive to humans and a small, but growing collection of birds and mammals, might be far more widespread throughout all the branches of the family tree of life. The ability for local traditions to develop and persist has been described as a hallmark of culture. While it is theoretically suggested that the social transmission of cultural traditions can exist outside of the non-human animals in which it is known, including less-cognitively advanced species, there is little empirical evidence for this. In addition, the processes underlying cultural inheritance is not well understood. Here, Etienne Danchin and colleagues propose a mechanistic definition of animal culture -- namely, some inherited traits be socially learned and spread to others -- and apply it to the mating routines of Drosophila melanogaster. Through a series of experiments in which female fruit flies were allowed to observe other females mating with various partners, Danchin et al. show that fruit fly females express a strong tendency to rapidly learn mating preferences from others and to copy them when choosing their own mate. Furthermore, a model based on the study's observations confirmed that these types of social learning and conforming can produce and maintain local traditions for potentially thousands of generations, with considerable evolutionary implications, according to the authors.
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Journal
Science