DARWINIAN METHODOLOGY AND THE THEORY OF INSECT HERBIVORE POPULATION-DYNAMICS

In his approach to the development of theory, Darwin set an example from which we can learn in our endeavors to develop a theory of insect herbivore population dynamics. Darwin was an accomplished naturalist; he relied on empirical observations and developed a factually based theory, building from the detection of pattern in nature to hypotheses on mechanisms accounting for pattern. Emulating Darwin's approach, patterns in plant, insect herbivore, and carnivore relationships, based on empirical observations, are summarized, arguing for recognition of strong influences passing up through trophic webs, from plants to herbivores to carnivores, and of pattern imposed by a landscape represented by all stages of ecological succession. Hypotheses accounting for linkage among the empirical patterns are erected in the form of flow diagrams of influence. Unanswered questions and the need for further testing of hypotheses are discussed in the hope of fostering more concentrated effort in the development of a theory on insect herbivore population dynamics.