Abstract
Two of the most important factors that contribute to the success of a parasite population are (1) the ability to find hosts and (2) the ability to oviposit in hosts when found. The theories of Thompson (1922, 1924), Nicholson (1933) and Nicholson and Bailey (1935), which have commanded attention in the field of population dynamics for a number of years, emphasized the importance of these factors in quite different ways.Thompson assumed that the parasites have no difficulty in finding their hosts but have a constant egg supply whereas Nicholson assumed that the egg supply is virtually unlimited but that the parasites have a fixed and limited searching ability which he called their ‘area of discovery’.