THE Population Biology OF THE Meat ANT

Abstract

AbstractData on the populations of the meat ant Iridomyrmex purpureus in the Canberra area, which were collected mainly over the period 1949 to 54, are analysed and discussed in relation to what is now known of the ecology of the species. The size of the oval mound nests of this ant is not always a good guide to the number of individuals in the colony, but the number of entrance holes seems to be proportional to the population of the nest. On a 65 ha study area the density of nests fell during the present study from 4.3 to 3.0 per ha, but the population of ants remained relatively stable as a result of two apparently regulatory processes. The numerical increase within each colony varied inversely with its initial size whereas the probability that the colony survived varied directly with the same parameter.The territories of colonies which died out were taken over, either by nearby colonies, some of the satellite nests of which then became independent, or by the founding of new colonies by young queens after their nuptial flights. Where colony budding is possible, the process appears to be a more effective method of colony foundation than for a single queen to attempt to start a new colony on her own.