|Two different ant species preserved in combat |
in 100 million year old Burmese amber
'We have one piece of amber with as many as 21 worker ants trapped, and that's significant because at this time period, ants are very rare to find in fossils,' said Dr Phillip Barden from Rutgers University. 'They make up less than one percent of all insects in amber, so to find 20 in one piece is highly suggestive of social behaviour.'
The ants themselves belonged to a lineage which is distinct from modern ants. Their ancient nature, however, suggests that social behaviours in the group are likely to be similarly ancient. These ants were certainly well equipped to defend territories they held, possessing tusk-like jaws which may have been used to impale prey.
'There's nothing like that alive today, especially not in the ant world' said Barden. 'It seems like they probably went extinct sometime in the 10 million years or so before or after dinosaurs went out. It could have been climate. We also think it's possible that the modern lineages actually out-competed these early ants.'
|A member of the reproductive caste of Krishnatermes yoddha|
Their presence in the same deposit as the ants opens up the possibility that the two species may have engaged in warfare, at the very least in defense of their respective territories. Ants today will often strip termite colonies of valuable resources, including the grubs which are then used as a food source. Such behaviours may also have been prevalent 100 million years ago.
Our views of past ecosystems often focus on megafauna. They are certainly impressive, but it is easy to forget about the multitude of species which dwell in the undergrowth and often in far greater numbers. Ants play a vital part in ecosystems today, engaging in multiple ecological roles from scavenging to pest control. They must have played similar crucial roles in the past. Further study of the fossil record, particularly of immaculate specimens preserved in amber, will shed light on how ants evolved to become colonial and even super-organismal entities and how this impacted on past ecosystems.