Application of plant life-history theory to strategies for breeding crop plants for sustainable agriculture remains relatively unexplored. We determined the relative tolerance of wild and domesticated tomatoes to simulated herbivory and evaluated plant characteristics that may contribute to tolerance. Wild and domesticated tomatoes were subjected to different levels of defoliation ranging from 0 to 70%. Single defoliation events at lower levels (15-30%) did not significantly affect total fruit mass produced in either wild or domesticated tomatoes. Increased defoliation resulted in significant reductions in total fruit mass per plant and mean mass per fruit. Reduction in fruit output by the cultivar was °3 times greater than the wild tomato for the first 8 wk of fruit production, whereas the loss in seasonal fruit production by the cultivar was 1.7 times greater than the wild tomato. We concluded that domestication of tomatoes may have decreased their relative tolerance to herbivory. Possible mechanisms for decreased tolerance include differences in leaf area index, light capture curves, and the relative allocation pattern to vegetative growth vs. reproductive structures. Optimization of potential life-history trade-offs between tolerance to herbivory and maximum fruiting abilities are proposed for cultivars of sustainable agriculture.
© 1993 by the Ecological Society of America.