30 
Psyche 
[Vol. 88 
In some cases, especially with P. montanus, the ants would 
attempt to tunnel under the enclosure. When this occurred, the ants 
were removed from the site of the tunneling and placed near the nest 
entrance inside the enclosure. In such cases the tunneling was 
completely controlled by destroying the tunnel system and replacing 
it with soil. 
The ants were allowed to enter and exit the colony through two 2 
cm diameter vinyl tubes, 6 cm in length. Entrance of the ants to the 
colony through the “exit” tube was prevented by having a 0.5-1 cm 
distance between the end of the tube and the soil. In a similar 
manner exit via the “entrance” tube was prevented. The ants were- 
apparently not affected by this short distance, they either simply 
dropped with no hesitation or rapidly climbed down from the tube 
to the soil. The tubes were within 15 cm of each other and were 
placed on the side of the nest where most of the foraging occurred. 
A 0.448 liter glass jar could be placed under the tube by which the 
ants entered the nest, thus collecting the foragers with the food items 
they carried. The foragers were counted and the food items 
collected. The foragers were released into the nest enclosure with a 
quantity of food (native seeds) which approximated the amount of 
food removed. The nests were sampled at approximately weekly 
intervals throughout the foraging seasons, during 1978 to 1980. All 
of the foragers entering P. montanus nests were collected, 1/5 to 1/6 
of those entering P. subnitidus nests, and 1 / 60 of those entering the 
P. rugosus nests. With these proportions, one person could handle 
the activity of 5 nests during a single day. The forager populations 
were estimated by capturing all of the foragers throughout the day, 
as they returned to the nests. 
Statistical analysis. 
Unless otherwise indicated, the 5% level of significance was used 
in all comparisons. A single asterisk indicates statistical significance 
at the 5% level, double asterisks at the 1% level, triple asterisks 
indicate significance at the 0.1% level. Means are listed plus or 
minus one standard error. The percentages of the nest populations 
were used to make comparisons between the species possible. The 
data obtained were fit to least squares polynomial regressions 
(Snedecor and Cochran 1967). The curves were constructed from 
the equations. 
