1981] 
Mac Kay — Nest Phenologies of Pogonomyrmex 
61 
Table 4. A comparison of the investments in production in three species of 
Pogonomyrmex harvester ants. 
Species 
Group 
Number of 
Individuals 
Dry wt 
(g) 
kcals 
Percent Total 
Production 
montanus 
Workers 
1516+ 95 
2.4 
12.7 
51.8 
Females 
187+ 30 
1.2 
7.8 
31.8 
Males 
239+ 41 
0.8 
4.0 
16.3 
24.5 
subnitidus 
Workers 
3988+438 
11.6 
87.4 
91.5 
Females 
111+ 65 
0.9 
5.4 
5.7 
Males 
251+ 87 
0.6 
2.7 
2.8 
95.5 
rugosus 
Workers 
5298+763 
30.3 
208.2 
86.6 
Females 
118+100 
2.7 
18.9 
7.9 
Males 
312+ 73 
2.5 
13.4 
5.6 
240.5 
Discussion 
Comparison with other species in the genus Pogonomyrmex. 
The genus Pogonomyrmex belongs to the tribe Myrmicini, one of 
the most primitive tribes in the subfamily Myrmicinae. The genus 
has existed at least since the Oligocene (Burnham 1978), and is 
distributed throughout North and South America from Canada to 
Patagonia, from sea level to at least 4500 meters in altitude. At the 
present time there are 24 valid species in North America and about 
33 in Central and South America. The genus may have originated in 
South America and migrated northward (Kusnezov 1951) or 
originated in North America and migrated southward (Wheeler 
1914; Creighton 1952). 
Considerable work has been done on nest densities, populations, 
and biomasses of ants of various species of the genus Pogono- 
myrmex (Table 3). Examples of biomasses from other genera would 
include the following (expressed as mg dry weight/ m 2 ), Tetramori- 
um caespitum at 200 (Brian et al. 1967) and 1480 (Nielsen 1974), 
Lasius niger at 60 (Odum and Pontin 1961) and 1060 (Nielsen 1974), 
L. alienus at 2090 (Nielsen 1974), L. flavus at 1400 (Odum and 
Pontin 1961) and 15,000 (Waloff and Blackith 1962), Leptothorax 
acervorum at 3000 (Brian 1956), and Formica rufa at 12,000 
