Can flies learn?

The fruitfly Drosophila melanogaster has boosted our understanding of genetics and developmental biology throughout the 1900s, culminating in the Nobel Prize award to Edward Lewis, Christiane Nüsslein-Volhard and Eric Wieschaus in 1995 "for their discoveries concerning the genetic control of early embryonic development". Its ability to learn is less well known.
In 1991 Martin Heisenberg and Reinhard Wolf published a study in which they used the Drosophila flight simulator to analyze operant conditioning. This work has spawned a variety of subfields, including pattern recognition, the biological substrate of memory and a behavioural analysis of the learning processes involved at the flight simulator. The flight simulator design allows to train and test the animals in several different basic operant and classical learning tasks. Starting from this general framework, I performed a thorough analysis of the learning tasks in my PhD thesis. This analysis was based on a comparative study of classical and operant pattern learning in Drosophila, my Diploma (Master's) thesis. All the experiments described in those two theses are presented together with extensive background information in the overview document "Fly Psychology?". Since then, we have found out that clkassical and operant learning processes indeed require different learning genes. This short article reviews the different genetic experiments and how they can be interpreted in our modern understanding of complex learning processes.

A fly strain mutant in one of the learning genes involved in the classical learning process, radish, even exhibits symptoms reminiscent of attention deficit and hyperactivity disorder (ADHD) in humans.