1981] 
Levings & Traniello — Territoriality in Ants 
281 
queen species like Oecophylla may be at a disadvantage. Resistance 
to invasion or persistance of the nest may be limited by the female’s 
egg production under some conditions, although this does not 
usually seem to be the case (Holldobler and Wilson 1977c; Holl- 
dobler and Lumsden 1980). We must emphasize that in populations 
with complex or variable structure it may be very difficult to 
determine the factors which are controlling distributions. Spacing 
may reflect foraging ecology as well as being an aspect of territorial- 
ity. More data are needed before good generalizations can be made. 
Behavioral and Ecological Aspects of Spacing 
For the cases we have been able to examine statistically, 67 out of 
80 show overdispersed nest distributions or tend toward overdisper- 
sed nest distributions. The other 80 cases, which cannot be treated 
statistically, mainly have either overdispersed nest distributions or 
tend toward overdispersed nest distributions. Thus the majority of 
species studied tend to have regular nest arrays. This pattern holds 
despite the large number of species, food types and habitats 
considered. Species which defend only their nests are too rare to 
consider in our sample. 
Our basic assumption is that no colony can become established or 
forage within some radius r of another colony. There is a biological 
basis for this assumption in the patterns of interference with colony 
establishment and foraging patterns. Therefore, to understand nest 
spacing it is important to understand the different levels of competi- 
tion in ant communities. Fertilized females or incipient colonies are 
usually destroyed when they are encountered by foragers from 
established colonies (Wilson 1971). The specificity of this behavior 
varies between species depending in part on population structure 
(Holldobler and Wilson 1977c, DeVroey 1979). There is some 
evidence that workers are more likely to attack females from 
conspecific nests or closely related species, especially in monogy- 
nous, queenright colonies, as has been shown in Pogonomyrmex 
(Holldobler 1976a) and Myrmecocystus (Holldobler, personal com- 
munication). The studies of Pontin (1960) and others (reviewed in 
Wilson 1971) suggest that such behavior is more often directed 
toward queens of the same species as the attacking workers. 
Another factor which may operate during this period is resource 
depletion mediated by either direct interference or exploitation. 
