dividing of niches among species so as to avoid interspecific competition.
Because interspecific competition is a between species, no gain from the interaction. It therefore can pay for organisms to on the exploitation of specific such that they can avoid interspecific competition.
Such specialization can result in resource partitioning, particularly if the specialization by different species is on different resources.
Resource partitioning is basically an issue of . When supply is low or demand is high, then the cost of obtaining a given item can be high. One way to maximize how many resources one can obtain therefore is to not seek out those things that others also are seeking out. The result of this approach can be a more complete utilization of available resources, with individuals avoiding competing over the same items by seeking out especially those things that are not in high demand by other individuals.
Another way of looking at this is that the one becomes then the less choosy one tends to be. In addition, the more one specializes on specific things then often the more effective one becomes at doing that specific thing (assuming in this case that some form of learning is possible).
One also can (arguably) view resource partitioning as being the consequence of a frequency dependent selection acting across multiple species. Those alleles that give rise to a tendency to exploit a more abundant resource will tend to be selected for within a community. The more alleles within a community that give rise to a tendency to exploit a given resource, however, then the more that resource will be depleted. Selection, therefore, should favor those rarer alleles that give rise to propensities to exploit resources that are not yet over exploited by a community.