Reading: priority effect--animal species, when first settling on certain territory, makes the territory less habitable for later species. This is esp. prevailing for small and weak species.
Listening: for example, there is a type of small ants that net on ankasha trees. As the first group of settlers onto the tree, they destroy part of tree’s nectars and render it unable to produce nectars anymore. This is because another type of bigger ants, which feed on this nectar and are more aggressive than smaller ants, will no longer come to this tree for occupation. Through this small ants survive.