Are There Really 30 Million Arthropod Species?
Part of what inspired Amy’s research was a theory put forth by Terry Erwin in the early 1980s. Erwin suggested that there might be 30 million species of arthropods, implying that for every one that has already been described there are 29 that are unknown, unnamed, and unclassified. Erwin’s statement was based on the assumptions that many arthropods are very picky about where they live and lay their eggs (this is called host specificity) and that there are twice as many arthropods that live only at treetop level as there are that live on the ground. It was a provocative statement that scientists have been debating ever since. But, as Amy pointed out, “We need people to go out and make wild speculations because it focuses research on areas that have been ignored. Erwin made everybody realize that we don’t know much about the host specificity of tropical arthropods, and we don’t know whether the canopy and ground faunas are distinct, and we don’t have any idea how many species exist. In f
