Evidence for Adaptive Variation in the Orientation of Amitermes (Isoptera, Termitinae) Mounds From Northern Australia

Abstract

Amitermes meridionalis and Amitermes laurensis construct meridional termite mounds that are endemic to northern Australia. The first comprehensive survey of the orientation of these mounds, involving 68 mound sites across northern Australia, is described. The mean mound orientations of most coastal A. meridonalis sites were significantly (P < 0.05) to the west of those of most inland A. meridionalis sites. The mean orientations of most A. laurensis sites in Cape York Peninsula were significantly (P < 0.05) to the west of those of most A. meridonalis and A. laurensis sites in the Northern Territory. Most shaded mound sites had significantly (P < 0.05) greater variance in mound orientation than nearby open sites. It is suggested that the geographic variation in mound orientation is an adaptive response to differences in local environmental conditions and that such variation provides the key to explaining the adaptive value of meridional orientation.