Fitness consequences of learning and memory traits investigated by artificial selection on learning rate
07 / 2009 - 10 / 2013
Insects can learn. Our previous work showed that some parasitic wasp species have an extremely high learning rate. When they find their host caterpillars on a certain plan species, they remember the odours of that plant in long-term memory and thereafter search specifically for plants of the same species to find more hosts. Other species, however, have a low learning rate and need repeated oviposition experiences spaced in time before they store information in long-term memory. In this project we want to investigate several aspects varying from gene expression to host-distribution, that are important for adaptations of learning and memory traits. The parasitic wasp species with a high learning rate will be subjected to a selection regime in which fitness will be related to learning rate. One selection line will be selected for a high learning rate; only wasps that form long-term memory after a single experience will be allowed to reproduce. A second line will be selected for a low learning rate; only wasps that do not form long-term memory after a single experience, but do form long-term memory after three oviposition experiences spaced in time are allowed to reproduce. The effects of this selection regime on learning and memory dynamics will be determined using specific inhibitors of short-, middle- and long-term memory. Furthermore, we will investigate the relation between differences in learning and memory and expression levels of memory-activating and suppressing genes, brain morphology and fitness parameters, under laboratory as well as semi-natural conditions. With these experiments, we want to learn more about key factors that determine the evolution of learning and memory.