A COMPARISON OF THE NEST PHENOLOGIES OF 
THREE SPECIES OF POGONOMYRMEX HARVESTER 
ANTS (HYMENOPTERA: FORMICIDAE)* 
By William P. MacKay 
Departamento de Entomologia 
Colegio de Graduados 
Escuela Superior de Agricultura 
Ciudad Juarez, Chih. Mexico 
Introduction 
Ants are among the most abundant animals in most habitats 
(Petal 1967) and may even be the dominant insects in many 
ecosystems (Nielsen 1972; Nielsen and Jensen 1975). Harvester ants 
of the genus Pogonomyrme x are a major component of the energy 
flux through ecosystems (Golley and Gentry 1964). Ants of this 
genus have become increasingly important in ecological studies, 
including mutualism (O’Dowd and Hay 1980), competition (Mares 
and Rosenzweig 1978; Reichman 1979; Davidson 1980), predation 
(Whitford and Bryant 1979), foraging (Whitford and Ettershank 
1975; Holldobler 1976a; Whitford 1976, 1978a; Davidson 1977a, b; 
Taylor 1977), community structure (Davidson 1977a, b; Whitford 
1978b), and impact on ecosystems (Clark and Comanor 1975; 
Reichman 1979). It is difficult to investigate harvester ants as 
seasonal processes occurring inside the nest are generally unknown 
and the nest populations are usually underestimated. 
This investigation compares the nest phenologies of three species 
of Pogonomyrmex harvester ants: P. montanus MacKay, P. 
subnitidus Emery, and P. rugosits* Emery, which occur at high, mid, 
and low altitudes respectively. These data form the basis for a 
comparison of the ecological energetics of the three species 
(MacKay 1981). 
Materials and Methods 
The species investigated. 
The altitudinal comparison is based on three species of harvester 
*This research constitutes Chapter 3 of a dissertaion submitted to the faculty of the 
University of California, Riverside, in partial fulfillment of the requirements for the 
Degree of Ph.D. in Population Biology. 
Manuscript received by the editor May 28, 1981. 
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