Distribution of Two Forms of the Meat Ant Iridomyrmex Purpureus (Hymenoptera: Formicidae) on Kangaroo Island and in the Yorke Peninsula.

Abstract

The geographical distributions of the meat ants Iridomyrmex purpureus, s.s., and a blue form of uncertain specific status were surveyed on Kangaroo I. and the Yorke Peninsula. The climate is mediterranean with dry summers, moderated in the south-west of land masses by maritime influences. The blue form occurs in areas of low rainfall; purpureus, s.s., is found in more humid areas but reaches a wet limit in western Kangaroo I. In the Yorke Peninsula, annual and summer rainfall determine three climatic zones. Only the blue form was found in the zone of lowest rainfal1, purpureus predominated in the high-rainfall zone, and both forms occurred in the intermediate zone where their relative frequency depended on soil properties, especially depth and texture.