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[Vol. 92 
Table 1. Reproductive status of inseminated and non-inseminated ants from a 
mature colony in terms of the number of ovarioles per ant which lacked oocytes. 
Ants were further classifiable into those collected before the nest was dug up (by 
“fishing”) and those collected during excavation. 
Number of empty ovarioles 
0 12 3 4 5 6 Total 
Non-inseminated 
fished 1 1 1 
excavated 68 
7 2 3 7 53 191 
0 1 0 0 15 85 
Inseminated 
fished 
excavated 
10 0 0 0 0 
3 1 10 6 1 1 
0 
0 
1 
22 
ants collected from it were packed tightly into the limited gallery 
space available. We dissected 230 ants from the incipient colony; 
about 30 more died before they could be dissected. None of the ants 
dissected were inseminated. The distribution of empty ovarioles for 
these individuals is shown in Table 2; it resembles that of the unin- 
seminated ants collected by digging from the mature colony (Table 
1), although it should be remembered that these two nests were 
collected almost two months apart. We found no eggs or larvae in 
the incipient colony, although partial excavations of mature colo- 
nies at that time yielded small larvae. 
Foraging interactions 
The nests in the study area are overdispersed (Crozier et al., 
1984), suggesting that there is foraging competition (Levings and 
Traniello, 1981). Given the relatedness between neighboring nests, 
and this a priori evidence for competition, investigation of various 
aspects of foraging behavior that pertain to these factors was carried 
out. 
We studied the foraging characteristics of one nest (number 54 in 
our system) in both September and November. The vegetation in 
the study area, chiefly herbaceous, was considerably more abundant 
in September than in November, with plants of Tetragonia tetrago- 
nioides (New Zealand Spinnache) being numerous in September but 
largely absent in November. This plant appeared to be particularly 
significant as a food plant for caterpillars, a major prey item. Even 
in September, however, the overall cover was not thick, with 33.7% 
of the ground bare, 58.1% covered by sparse herbs, 6.7% with a 
