A new-found colony of hairy ants could be the most northerly on the west coast of Scotland, the National Trust for Scotland (NTS) has said.
The population was recorded in a survey of the trust's Balmacara Estate in Ross-shire by Murdo Macdonald of the Highland Biological Recording Group.
The colony has been described as "isolated" but NTS said further surveys may uncover more nests in the area.
Hairy ants are larger than more common Scottish wood ants.
NTS said the nearest population to Balmacara was in Glen Affric, 24 miles (40km) away.
Mr Macdonald said wood ants were key to the biodiversity of forests and their numbers have been in decline through loss of woodland.
He added: "Finding hairy wood ants at Balmacara is very significant, because we've located a pocket of survivors that were previously undiscovered.
"It's also the most northerly colony known on the west coast, and a very isolated group. That could suggest that there may be other, as yet, unknown populations out there in the north west."
NTS conservation officer Barbara Macritchie said: "We'll be making sure that our plans to manage the estate protect these important insects, ensuring that their habitat is conserved and they can continue to survive in this area for years to come."