Ants evolved far earlier than previously believed, as far back as
140 million to 168 million years ago — and they have plants to thank
for their diversity, U.S. researchers reported on Thursday.

A
team at Harvard University who used a genetic clock to reconstruct the
history of ants found the ant family first arose more than 40 million
years earlier than previously thought, but did not diversify into
different genera and species until flowering plants came onto the scene.

The study sheds light on one of the most important and numerous animals, which includes hundreds of different species.

"We
estimate that ant diversification took off approximately 100 million
years ago, along with the rise of flowering plants, the angiosperms,"
Naomi Pierce, a professor of biology who led the study, said in a
statement.

"These plants provided ants with new habitats both in
the forest canopy and in the more complex leaf litter on the forest
floor, and the herbivorous insects that evolved alongside flowering
plants provided food for ants."

Writing in the journal Science,
the researchers said they reconstructed the ant family tree using DNA
sequencing of six genes from 139 ant genera, encompassing 19 of 20 ant
subfamilies around the world.

Such "molecular clocks" are widely
used, alongside fossil and other evidence, to determine how old species
are. They work on the basis that DNA mutates at a steady and calculable
rate.

"Ants are a dominant feature of nearly all terrestrial
ecosystems, and yet we know surprisingly little about their
evolutionary history: the major groupings of ants, how they are related
to each other, and when and how they arose," said graduate student
Corrie Moreau.

reuters.com