NATAL NEST DISTRIBUTION AND PLEOMETROSIS 
IN THE DESERT LEAF-CUTTER ANT 
ACROMYRMEX VERSICOLOR (PERGANDE) 
(HYMENOPTERA: FORMICIDAE) 
By Steven W. Rissing,* Robert A. Johnson,* 
and Gregory B. Pollock** 
While most ant colonies are started by single queens, colony 
foundation by groups of queens, pleometrosis, also occurs (Wilson 
1971, Holldobler and Wilson 1977). Several extensively studied, 
highly pleometrotic species are notably similar with respect to 
important aspects of colony ontogeny and population dynamics. 
Myrmecocystus mimicus, Solenopsis invicta and Veromessor per- 
gandei queens found colonies mutualistically without respect to 
relatedness (Bartz and Holldobler 1982, Tschinkel and Howard 
1983, Pollock and Rissing 1985, Rissing and Pollock 1986). Further, 
while adult colonies of these species are highly territorial (Holl- 
dobler 1976a, 1981; Wilson et al. 1971; Went et al. 1972, Wheeler 
and Rissing 1975), natal colonies are clumped with brood raiding 
and subsequent worker defection from brood-raided colonies occur- 
ring (references cited above for M. mimicus and S. invicta, for V. 
pergandei: Rissing and Pollock, in press). Given such frequently 
deleterious natal colony interactions, adaptive value of habitat 
selection by founding queens resulting in clumping of natal nests is 
unclear. Natal nests of M. mimicus are generally clumped in areas 
devoid of adult nests (Bartz and Holldobler 1982), yet still occur 
near such nests (B. Holldobler, pers. comm.), and queens of S. 
invicta show some preference for microtopographic features 
(Tschinkel and Howard 1983). Here we present data relating habitat 
selection and clumping of natal nests of the highly pleometrotic leaf- 
cutter ant Acromyrmex versicolor (Pergande) directly to survival of 
founding queens. The only other report regarding any aspect of 
colony initiation in this species is a description of mating flights 
following summer rains in the Sonoran Desert by Wheeler (1917). 
♦Department of Zoology, Arizona State University, Tempe, AZ 85287 
♦♦School of Social Science; University of California, Irvine; Irvine, CA 92717 
Manuscript received by the editor April 6, 1986. 
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