Among the factors which have significant roles in determining the success of plants, herbivory is known to affect both viability and fertility components of fitness. Herbivory is also known to influence the relative allocation of biomass production to leaves, roots, storage tissue, and to reproductive tissue. While the effects of herbivory can be lethal to individual plants, the more likely effects are to reduce the realized fitness of damaged plants to below that of plants which escape herbivory. Although it has been proposed that adaptation in response to the pressure of herbivory might select for genotypes which can tolerate or even flourish under a regime of herbivory, supportive data are scant and the idea remains controversial. This simple study examines, under controlled conditions, the effect of simulated minor early foliage herbivory on Raphanus sativus. The study measures (1) the accumulation of biomass, (2) the allocation of biomass to above-ground biomass versus below-ground (storage) biomass, and (3) the production of flowers and seeds. As expected, treated plants were consistently smaller at every stage; treated plants consistently allocated a larger fraction of their production to above-ground biomass, affecting the root/shoot ratio. In terms of reproductive performance, however, effects were less clear.

Key words: fitness, herbivory, Raphanus