English: Island Gigantism: This diagram displays the change of the weta species in two different ecosystems. The physical size and the population size of the weta is affected by the predation rate. A species of rat was introduced on the mainland. The rats then began to take over and prey on wetas. The high amount of a foreign predators decreases the amount of wetas drastically. As shown on the diagram, the weta shrinks in size, representing the drop in population and health of the species. The bottom diagram displays island gigantism. Island gigantism is the principle that species on an island isolated from predation will thrive due to more resources and less predation. The wetas are an example of this because on Little Barrier Island they have grown to a massive size for their species and have a high population. The Little Barrier Island wetas do not have rats preying on them, unlike those on the mainland. This has enabled them to grow to their great size. The giant weta species on islands are the only ones not facing extinction due to their geological advantage of being separated from the introduced rats. The diagram shows the growth of the weta as time goes on while also displaying how the birds begin to prey on them less due to their size.