Colony dispersion and relationships of meat ants iridomyrmex purpureus and allies in an arid locality in southern australia
Greenslade, P.J.M.; Halliday, R.B.
Insectes Sociaux 30(1): 82-99
ISSN/ISBN: 0020-1812 DOI: 10.1007/bf02225659
The distributions of 3 forms, actually sibling species, of meat ant were studied near Morgan, southern Australia, an area with mean annual rainfall of 230 mm. Colony dispersion is described for a blue form and for form I. purpureus s.s. which occurs in this locality far beyond its normal low rainfall limit. An unusually large colony of I. purpureus had a territory covering 10 ha with more than 85 nests and over 1500 individual nest entrances. Worker interactions betweeen forms and within and between colonies within forms are described. The ant fauna of the locality as a whole and the faunas accompanying different Iridomyrmex spp. were investigated by means of hand collections and pitfall trapping. Diversity (species-richness) and the occurrence of widely adapted ant species are related to vegetation type and associated Iridomyrmex. Catches of pitfall traps suggested that the numbers of individuals and species of other taxa active on the soil surface, predominantly Collembola, were affected by numbers of ants, particularly Iridomyrmex sp. and other widely adapted ants. Iridomyrmex also influence associated fauna at an evolutionary level. The presence of zodariid spiders which are sibling species-specific color mimics and predators of meat ants is noted. Possible cases of mimicry of meat ants by ants of the genus Camponotus are recorded and discussed.