Evolutionary ecology of learning: insights from fruit flies
- 663 Downloads
Ecologically and evolutionarily oriented research on learning has traditionally been carried out on vertebrates and bees. While less sophisticated than those animals, fruit flies (Drosophila) are capable of several forms of learning, and have the advantage of a short generation time, which makes them an ideal system for experimental evolution studies. This review summarizes the insights into evolutionary questions about learning gained in the last decade from evolutionary experiments on Drosophila. These experiments demonstrate that Drosophila has the genetic potential to evolve a substantially improved learning performance in ecologically relevant learning tasks. In at least one set of selected populations, the improved learning generalized to a task other than that used to impose selection, involving a different behavior, different stimuli, and a different sensory channel for the aversive reinforcement. This improvement in learning ability was associated with reductions in other fitness-related traits, such as larval competitive ability and lifespan, pointing to evolutionary trade-offs for improved learning. These trade-offs were confirmed by other evolutionary experiments where a reduction in learning performance was observed as a correlated response to selection for tolerance to larval nutritional stress or for delayed aging. Such trade-offs could be one reason why fruit flies have not fully used up their evolutionary potential for learning. Finally, another evolutionary experiment with Drosophila provided the first direct evidence for the long-standing idea that learning can under some circumstances accelerate and in others slow down genetically based evolutionary change. These results demonstrate the usefulness of fruit flies as a model system to address evolutionary questions about learning.
KeywordsBehavior Drosophila Experimental evolution Learning Memory Trade-offs
This work reported here was supported by the Swiss National Science Foundation, the Roche Research Foundation and the Velux Foundation.
- Falconer DS, Mackay TFC (1996) Introduction to quantitative genetics, 4th edn. Longman, HarlowGoogle Scholar
- Fontanari JF, Meir R (1990) The effect of learning on the evolution of asexual populations. Complex Syst 4:401–414Google Scholar
- Hinton GE, Nowlan SJ (1987) How learning can guide evolution. Complex Syst 1:495–502Google Scholar
- Papaj DR (1994) Optimizing learning and its effect on evolutionary change in behavior. In: Real LA (ed) Behavioral mechanisms in evolutionary biology. University of Chicago Press, Chicago, pp 133–154Google Scholar
- Schlichting CD, Pigliucci M (1998) Phenotypic evolution. A reaction norm perspective. Sinauer, SunderlandGoogle Scholar
- Shettleworth SJ (1999) Cognition, evolution, and behavior. Oxford University Press, OxfordGoogle Scholar
- Stearns SC (1992) The evolution of life histories. Oxford University Press, OxfordGoogle Scholar