ECOLOGY AND LIFE HISTORY OF THE 
RHYTIDOPONERA IMPRESS A GROUP 
(HYMENOPTERA:FORMICIDAE) 
I. HABITATS, NEST SITES, AND FORAGING BEHAVIOR 
By Philip S. Ward 1 
Department of Zoology, University of Sydney, 
N.S.W. 2006, Australia 
Introduction 
The ponerine ants of the genus Rhytidoponera constitute a rich 
assemblage of species, widespread throughout Australia, with lesser 
representation in Melanesia and adjacent regions (Brown, 1958; 
Wilson, 1958). On the Australian mainland they have collectively 
occupied a broad range of habitats, and often rank among the more 
abundant members of an ant community. Considerable interest 
centers on the unusual habit, apparently widespread in the genus, of 
reproduction by mated “workers” in lieu of a morphologically 
differentiated dealate queen (Brown, 1953, 1954; Whelden, 1957, 
1960; Haskins & Whelden, 1965). 
The Rhytidoponera impressa group consists of a small, distinctive 
cluster of species occurring in mesic habitats (mostly rainforest and 
wet sclerophyll) along the east coast of Australia and in New 
Guinea. Until recently, the impressa group was thought to comprise 
no more than three species, all reproducing by means of distinct 
winged queens (Brown, 1953, 1954; Haskins & Whelden, 1965). 
However, recent studies of systematic relationships and colony 
structure in the impressa group have revealed the presence of at least 
5 close^ related species and the occurrence of reproduction by both 
queens and mated workers (Ward, 1978, 1980). 
There is a notable paucity of detailed ecological studies on 
rainforest ponerines in general, and there have been no extensive 
field studies on Rhytidoponera. This paper summarizes information 
on habitat and nest site preferences, colony densities, and various 
aspects of foraging, in the impressa group. A second paper describes 
life cycle and reproductive patterns (Ward, 1981). 
'Present address: Department of Entomology, University of California, Davis, 
California 95616 
Manuscript received by the editor April 15, 1981. 
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