352 
Psyche 
[Vol. 89 
their co-occurrences with other species is given in Table 1. Pseudo- 
myrmex pallida is by far the most frequent ant, found in 57 culms or 
48% of the total. Tapinoma littorale (Wheeler) and Solenopsis picta 
are each found in approximately 10% of the total. 
The co-occurrence of series are also given in Table 1. Solenopsis 
picta is found frequently with other species including P. pallida, 
Zacryptocerus varians (F. Smith), and Camponotus planatus 
(Roger). No other ant species co-occur with P. pallida. T. littorale is 
the only species frequent enough to examine statistically. If P. pallida 
and T. littorale assorted into culms independently of one another, the 
expected number of co-occurrences would be 5.75. T. littorale never 
co-occurs with P. pallida, a difference that is statistically significant 
(X 2 = 11.0, p< 0.001). 
It is possible to calculate the probability that S. picta should be the 
only species that co-occurs with P. pallida. This calculation can be 
done independently of our knowledge that T. littorale is negatively 
associated with P. pallida (p = 0.002) or contingent on our knowledge 
of this relationship (p = 0.02). In either case, it is shown that if any 
species occurs with P. pallida it is likely to be S. picta. It is not 
possible to statistically demonstrate the stronger statement that S. 
picta is positively associated with P. pallida. Indeed, this seems not to 
be the case due to co-occurrence of 5. picta and other species. 
If one combines the data of Z. varians, C. planatus, Leptothorax 
allardvcei (Mann) and Pseudomyrmex elongatus (Mayr), one can 
also demonstrate that this aggregate is negatively associated with P. 
pallida (X 2 = 12.0 p < 0.001). Due to the relative rarity of these 
species, one cannot test each species individually. This result must 
be considered tentative. 
Table 2 gives some characteristics of the nests of the guild of 
sawgrass inhabiting ants. The average inside diameter and standard 
deviation of internodes occupied by P. pallida is calculated sepa- 
rately for that subset of the colonies that occupy a single internode 
and for that subset that occupy more than one internode. Nests of P. 
pallida that occupy a single internode have an inside diameter of 
2.38 mm. The inside diameter of internodes occupied by P. pallida 
that are found in two internodes are 2.45 and 2.03 for the lower and 
upper chamber respectively. The diameter of the single nest chamber 
does not differ from that of the lower nest chamber of a P. pallida 
colony that occupies two chambers (t s = 0.53, p > 0.5). 
