The impact of herbivory on plant numbers in all life stages of Cynoglossum officinale L. and Senecio jacobaea L.

Striking differences in herbivory were found between Cynoglossum officinale and Senecio jacobaea, two common and equally apparent plants. C. officinale was only influenced by herbivores during seed stage (maximal seed predation: 31%). S. jacobaea, in contrast, suffered severely from herbivory during all life stages. Seed number was strongly reduced by seed predation (65%). Rabbit activity in winter significantly reduced the probability of flowering. In summer, larvae of Tyria jacobaeae reduced the seed production to zero. The differences in herbivory between the two plant species are discussed in relation to plant defensive characteristics.