Why are there different types of mounds and nests?
Given that their nests and mounds appear to provide stable internal conditions for termites in a wide range of environments it is perhaps not surprising that many nests appear to be shaped to suit those different environments. This is seen in Amitermes laurenis: in well-drained habitats it builds small dome-shaped mounds, yet in seasonally flooded flats it constructs huge mounds aligned along a north-south axis, often hundreds of times larger. Studies on this species and A. meridionalis, which also builds oriented mounds, suggest that such mounds are an adaptation to the seasonally waterlogged conditions: the high surface-area shape oriented north-south creates a stable environment for living above the ground in flooded habitats where migrating to an underground refuge is impossible. Recent genetic studies imply this behaviour may have evolved several times and more than once within A. laurensis (references 8 and 9).
