Components of environment: mates

Abstract

Andrewartha and Birch (1954) recognized a component of environment ‘other animals of the same kind’ which they discussed under two major headings ‘underpopulation’ and ‘crowding’. The disadvantages of living in a sparse population were discussed in relation to (1) the risk of not finding a mate and (2) the risk that some other component of environment might be less favourable for individuals in a sparse population. The disadvantages of living in a dense population were discussed in relation to (3) the risk of generating a shortage of resources, (4) the risk of stimulating the multiplication of predators by providing them with an abundance of food and (5) the risk that intraspecific aggression might adversely influence the physiological condition of animals living in a dense population thereby reducing their chance to survive and reproduce.