When cabbage plants are nibbled by insects, they form bitter substances (mustard oils). As insects do not like the taste of these, they usually look for another plant. The caterpillars of the cabbage butterfly (Pieris brassicae) however are adapted to the cabbage plants’ bitter substances and continue eating.
In order to deter the caterpillars despite this, the cabbage plants exude fragrances. These chemical signals attract white butterfly parasites (Cotesia glomerata) that lay their eggs into the caterpillars of the cabbage butterfly, thus killing them — good for the cabbage plants!
iDiv scientists are conducting experiments to show how plants try to fend off natural enemies. The results are used in agriculture and plant breeding. An experiment to study the bitter substances is set up in the exhibits.