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This cathedral mound could be more than 100 years old—and so
could the queen termite within it Photo: David Curl
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How old are the anthills or termite mounds that dominate some
landscapes in the tropical savannas? The short answer is that it's
difficult to tell. Unlike trees and corals termite mounds don't
seem to have regular growth rings, so they can't be aged simply by
looking at the finished product.
You can of course keep an eye on a particular mound over the years
and this shows that some mounds must be pretty old.
A 'cathedral' mound (these are the large buttressed mounds that are
often more than 5 metres tall) of the spinifex termite Nasutitermes
triodiae had to be "topped" when the Overland Telegraph was
constructed in the 1880s because it interfered with the wires. It
was still a thriving colony around 50 years later in 1936 and by
the 1950s it was in a state of advanced decay.
As it was over 3 metres high when it was topped it was probably at
least a few decades old then, giving a total age of around 100
years.
The remarkable thing about this record is that the spinifex termite
is thought to have colonies dependent upon a single queen, in other
words when she dies she is not replaced and the colony no longer
produces eggs and will start to decline.
This implies that the queens of the spinifex termite live for many
decades making them among the oldest insects in the world.
By Peter Jacklyn
