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Psyche 
[Vol. 88 
Levings and Franks (1982) have reviewed the relevant statistical 
literature and give a suggested procedure for examining this 
problem. 
In addition to changes in the observed spatial array of any one 
species, in multi-species populations, there should be correlated 
changes in expected internest distances under different competitive 
regimes. If intra- and interspecific interactions are equally strong, 
the average internest distance within any one species should be 
longer than twice the species’ average r and the variance in between 
nest distances within any one species should be high (essentially a 
low density population, Case 2). If intraspecific interactions are 
more important than interspecific interactions, then internest dis- 
tance within any one species should be greater than twice the 
species’ average r and their variance should be relatively low. The 
exact predicted distance will be a function of the number of 
interacting species and their relative abundances. It may be possible 
to use the degree of departure from predicted intraspecific spacing 
patterns as a measure of competition between species in homog- 
enous habitats. If intranest distances within a species are 2 r, then it 
does not appear to be interacting significantly with sympatric 
species, at least not in ways which affect its spatial distribution. 
Detection of Overdispersion and Methodological Problems 
There are certain methodological difficulties in applying any sort 
of spatial analysis to previously published data on nest distribu- 
tions. In particular, the complicated structure of the nests of many 
species has confused workers, especially when many nest entrances 
are present. In Lasius neoniger, Headley (1941) assumed that the 
species was unicolonial, since he could only occasionally elicit 
aggression between adjacent nest entrances. In fact, L. neoniger 
colonies are distinct and well organized, but extensive field tests are 
required to delineate colony boundaries (Traniello 1980). Simple 
mapping of nest openings may reflect the distribution of colonies 
fairly well (as it does for many species in the ground ant community 
in Panama, Levings and Franks 1982; Levings, personal observa- 
tions), but may lead to confusion unless sufficient data on the 
species are available (see, for example, Brough 1976). Whitford et 
al. (1980) assumed that workers of Novomessor cockerelli were 
entering an alien nest because they did not return to the same nest 
