Maternal Investment, Female Rivalry, and a Fallacy

Abstract

fitness of other individuals is reduced even more. Grazing may well result in short-term reduction of individual relative fitness, but it prolongs life to an extent that long-term fitness is increased. Our hypothesis applies mainly to large, long-lived, vegetatively reproducing, ramet-forming grasses characteristic of natural grasslands where natural grazers occur. These grasses, in our view, do not form climatically determined climax communities; rather the climax is achieved by grazing. Gardeners, whose intuitive knowledge is extensive, recognize that cutting and pruning a tree or shrub can result in more flowers and hence potentially more seed. Coppicing and pollarding can prolong the life of a tree. Of course, gardeners and trees are not co-evolved and there is unlikely to be en evolved mutualistic relationship between them. Nevertheless there may be something in the old English proverb, A wife, a dog, and a walnut tree, the more you beat them the better they be. Among the various interpretations of this proverb is the suggestion that beating was seen as a means of increasing reproduction. Breaking the branches of a tree by beating results in new growth and eventually a better crop of walnuts. We do not feel inclined to speculate about wives and dogs, but for walnut trees there are distinct possibilities, just as there are for grazed grasses.