1981] 
Levings & Traniello — Territoriality in Ants 
271 
entrance from which they departed. However, Holldobler et al. 
(1978) and Davidson (1980) documented that this species has nests 
with multiple entrances. 
Although there are several methods for the detection of over- 
dispersion (Pielou 1977), we have chosen to apply Clark and Evans’ 
(1954) nearest neighbor (NN) technique wherever possible. It is 
based upon the ratio between the observed mean nearest neighbor 
distance and the expected distance when a population is distribution 
at random. The index R can range from 0 (perfect aggregation) to 
2.1491 (perfect hexagonal overdispersion). A value of 1 indicates a 
random dispersion pattern. The significance of R is tested using the 
z transformation. In an overdispersed population, the observed 
mean nearest neighbor distance is larger and the variance in nest to 
nest distance is lower than it would be in a randomly distributed 
population. Thus a population which is significantly overdispersed 
using this measure confirms 2 of our predictions (overdispersion 
and low variance in NN distance). Other methods do not have this 
property. 
In our evaluation of spacing information in the literature, if we 
were unable to apply nearest neighbor methods, but complete 
quadrat counts were published, we calculated variance/ mean ratios 
and tested them for significance using X 2 statistics (Pielou 1977). A 
V/M ratio of less than 1 indicates overdispersion while values 
greater than 1 indicate clumping. Cases are included in which data 
are not sufficient to test for statistical overdispersion, but informa- 
tion on partitioning of resources or area was published. We have 
organized the available data by geographic region, habitat and food 
types (Table 1). Methods used in gathering previously unpublished 
data will be described with the specific set of data. In testing our 
model and spatial predictions from the literature, we are limited by 
the previous interests and focus of other authors. We are able to test 
the spatial predictions far more thoroughly than the hypotheses 
about the actual expected distances between nests, but there is no 
empirical reason that they cannot be experimentally verified in the 
field (see discussion). 
Data are discussed by subdividing reported cases into groups 
according to foraging type: (1) species which do not defend re- 
sources although they may or may not recruit to food, (2) species 
which defend randomly and unpredictably distributed resources 
(e.g., dead insects, which are patchy in both space and time), (3) 
