26 
Psyche 
[Vol. 88 
ants: Pogonomyrmex montanus MacKay, P. subnitidus Emery, and 
P. rugosus Emery. All three belong to the subgenus Pogonomyrmex. 
Pogonomyrmex subnitidus and P. montanus are very closely 
related, both belong to the occidentalis complex (MacKay 1980). 
Pogonomyrmex rugosus belongs to the barbatus complex (Cole 
1968). Pogonomyrmex montanus is unusual for the genus in being a 
high mountain species occurring in pine forests in the mountains of 
southern California. Pogonomyrmex subnitidus is a mid-altitude 
species in the San Jacinto Mountains. Pogonomyrmex subnitidus is 
distributed throughout southern and south central California and 
Baja California, occurring at lower elevations throughout much of 
its range. Pogonomyrmex subnitidus is sympatric with P. rugosus in 
parts of Riverside County, but is uncommon in such areas. 
Pogonomyrmex rugosus is a low altitude species near Riverside and 
occurs at lower elevations throughout much of southwestern United 
States. It rarely occurs at higher elevations. For example, in the 
Joshua Tree National Monument it is present up to 1350 meters, in 
New Mexico it occurs at over 2100 meters. 
Study areas. 
Populations of all three species were studied in southern Cali- 
fornia: P. montanus — in a yellow pine forest community between 
Fawnskin and Big Pine Flat at 2100 meters elevation in the San 
Bernardino Mountains of San Bernardino Co., P. subnitidus — in 
the chaparral near the Vista Grande Ranger Station at 1500 meters 
in the San Jacinto Mountains of Riverside Co., P. rugosus — in the 
coastal sage scrub community at Box Springs at 300 meters near 
Riverside, Riverside Co. The three species occur in clearings within 
these different plant communities. 
Estimation of nest populations. 
Two primary methods are used in the estimation of ant nest 
populations: mark-recapture methods and nest excavation. Mark- 
recapture methods are used to compare a population before and 
after seasonal production. This method has been criticized as one of 
the assumptions is that workers mix randomly in the nest. The 
workers of all three species are stratified within the nests and there is 
strong evidence that other species are stratified as well (MacKay 
1981). Also I could find no reliable way to mark the individuals such 
that the marks were permanent, could not be passed on to other 
individuals, and would not disrupt normal activities. In any case, 
