Institut für Pharmazeutische Biologie der Technischen Universität, Mendelssohnstrasse 1, 3106 Braunschweig, Germany.
Senecio jacobaea produces different pyrrolizidine alkaloids (PAs) of the senecionine type, which are used for defence against herbivores. In evolutionary processes some insects, however, evolved detoxifying mechanisms. They can feed on S. jacobaea without beeing deterred by PAs. There are even adapted insects (e.g. Tyria jacobaeae) that can feed on S. jacobaea and store plant derived PAs against insectivores. The damage on S. jacobaea caused by T. jacobaeae can be considerable. Populations and individual plants are known to differ quantitatively and qualitatively in their PA content. The ability of populations to create great chemical variability is interpreted as a defence strategy against herbivores.To obtain deeper insight into the evolutionary dynamics of quantitative and qualitative variability of PA production in S. jacobaea, different studies were performed. The studies concern genetic variation and ontogenetic aspects of PA-synthesis in S. jacobaea.