Predator–prey interaction between individuals: 1. The role of predators in natural selection

Abstract

Interactions in food chains are analyzed in terms of hunt success and selective elimination of prey by predators. This problem is important to understand the selective effect of predation. The examination of remains of the prey of wild predators does not reveal the reasons for elimination of particular individuals. A model of wild canids hunt was developed with the help of windhound dogs, which made it possible to analyze the procedure of pursuit and inspect the entire the prey but not only its parts. Was proved that the predator’s coursing speed is not the major factor in prey capture. The windhound’s hunt success was found to be 27% for saiga antelope and 12% for brown hare (of the number of pursuits). Hunt success in wild predators (large felids and canids) is usually less than 50% but sometimes may reach this value. The low efficiency of windhound hunt is the result of selection by chasing any prey without a preliminary estimation of pursuit perspectives, which is typical for wild predators. The use of windhounds for hunting wild animals revealed that only unhealthy animals were eliminated by the dogs: the saiga antelopes had some pathology of internal organs, and the brown hares caught by dogs were in a poorer condition than those killed by hunters. The abnormalities established in saiga antelopes could not be found when examining the remains of wild predator prey. The low hunt success is combined with a very high selectivity. Thus, the preliminary assessment of the accessibility of prey by predators is unreliable; however, the elimination of any deviations that decrease the adaptability of prey is effective. A predator is a universal breeder that removes adverse deviations from the populations of consumers of the first level, thereby preserving the adaptability of phenotypes and the population norm.