This competition occurs when the first group of species increases in number. This, in turn, results in the increase in number of predators in the area. With the increase in the number of predators, this also means that there are more predators hunting for the other group of species in the area.
An example of this competition is the competition between nettle aphids (prey A) and grass aphids (prey B) in the area. Both of these organisms are prey to Coccinellidae (predator). The increase in the population of grass aphids (prey B) attracted more Coccinellidae (predator) in the area, resulting in increased predation of Coccinellidae of nettle aphids (prey A)1.
Types of competitions based on the mechanism used are:
Reference: 1 Muller, C. and Godfray, H. (1997). Apparent competition between two aphid species. Journal of Animal Ecology 66(1): 57-64.