Before revision:  For example, a pollination interaction may be particularly likely if the proportions of a bee's tongue match flower shapein a beneficial way. Empirical evidence for trait matching , however, varies significantly in strength among different types of ecological networks.
After revision:  For example, a pollination interaction may be particularly likely if the proportions of a bee's tongue fit a plant's flower shape. Empirical estimates of the importance of trait-matching for determining species interactions , however, varies significantly in strength among different types of ecological networks.