Typically, these interactions are classified based on whether they are beneficial to one or both of the species involved or whether they are detrimental to one of the species involved. The niche of each species is a little different to avoid competition. Different species, even closely-related ones, will have different food preferences, seasonality, daily feeding rhythms, and location within the habitat. For some species of katydids within the same genus, the difference may be as subtle as a preference for perching on the top vs the middle of a stem on a grass plant. This is a general term which includes predation, parasitism, commensalism, mutualism, etc., but often is used to mean mutualism.
Lions eat antelope, and wolves eat deer.
Spiders, like this orbweaver, capture and eat insects. Commensalism A relationship between two species that is beneficial to one but of neutral benefit to the other. Cattle egrets follow cattle to feed on the insects stirred up by the grazing cattle. Mutualism A relationship between two species where both benefit. Many plants and their pollinators have evolved mutualistic relationships.