1979] McCluskey & Soong — Rhythm Variables in Ants 101 
Summary 
In the field the time of day of certain types of behavior distin¬ 
guishes various species and genera. Would the same be true if their 
habitats were made identical? And could rhythm-related variables in 
general be regarded as taxonomic characters? Groups of workers of 
Pogonomyrmex californicus, P. rugosus, Veromessor andrei, V. 
pergandei, Formica pilicornis, and Myrmecocystus mimicus were 
studied simultaneously in constant temperature and alternating 
light and dark. A hot dry area and a dark humid area were available 
in each nest for choice at all hours. This permitted different types of 
position or activity assays and the calculation of several cosine- 
fitted rhythm parameters for each. These as well as simple hourly 
values served as variables. For most of the variables tested there was 
a significant species difference. With multidiscriminant analysis it 
was possible to go beyond this general species difference and segre¬ 
gate the replicates of each species from those of other species; either 
the hourly or the more highly processed variables were adequate 
here. This study suggests a variety of rhythm-related characters that 
might be observed in laboratory or field. 
Acknowledgments 
The data on which this report is based are largely from the second 
author’s M.A. thesis research (Loma Linda University, 1975). We 
thank Andre Francoeur for determining F. pilicornis and Roy Snel- 
ling, M. mimicus; Glen McCluskey and Duane Zimmerman for 
programming; Paul Yahiku and Richard Pimentel for statistical 
help; and Leonard Brand, Conrad Clausen, David Kissinger, Gerald 
Scherba and Paul Yahiku for reading earlier drafts of the manus¬ 
cript. Computer time was supported in part by NIH, Grant RR- 
00276. Also used were BMDP programs developed at UCLA with 
NIH support. 
Literature Cited 
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Cole, A. C. 
1932. Notes on the ant Pogonomyrmex californicus, Buckley (Hym.: Formici- 
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