Washington, May 22 (IANS) Ants fend off competing plant species by marking their host tree with chemical signals in the depths of tropical rainforests."The ants inhabit hollow channels inside the tree and aggressively fight off any invaders, including other plants. Yet how these ants recognise their host tree compared to other plants has not been studied," said lead author Tiffany Weir from Colorado State University.

"We found that the ants distinguish between their host trees and encroaching species through recognition of the plant's surface waxes," Weir said, according to a report in the journal Biotropica.

From the Tambopata National Reserve in Peru, Weir and Jorge Vivanco, the team's leader, used a creative set of experiments to show how ants inhabiting the branches of T. Americana trees recognise species-specific chemical signals embedded in the leaf surface.

Species of grass and fern were harvested from the area and replanted around several T. Americana trees which hosted ants. The team then monitored ant pruning behaviour of these competing species for five weeks, according to a Colorado statement.

Detached leaves from several trees, including T. Americana, were then attached to host trees with a sewing pin. Daily records revealed that more leaves belonging to non-host plants were removed by the ants.

The team also found that even during rainy periods when ant activity was minimal, they still defended their host tree if disturbed. This included attacking ants from a neighbouring nest if they ventured too close to the tree.