Each year painted lady butterflies migrate thousands of miles from north Africa, the Middle East and central Asia to recolonise Europe, reaching the UK in late summer.
But every ten years they appear in huge quantities.
More than 11 million were recorded during a mass influx in 2009, thought to be one of the biggest ever.
But experts believe there could be even greater numbers appearing this year.
Weather and food sources are providing ideal conditions for the species to thrive.
A number of sightings have already been recorded across Scotland.
Conservationists at the National Trust for Scotland (NTS) are enthusiastic about the latest “mass emergence”.
Kevin Frediani, operations manager at the NTS’s Inverewe Gardens in Wester Ross, said: “The science behind their migration is fascinating.
“Painted lady butterflies are a normal sight in Britain during the summer months and are frequently seen here at Inverewe in July and August.
“But once every decade the UK experiences a huge influx from Europe, and this year looks like one of those years.”
Gavin Smith, first gardener at Hill House in Helensburgh, said: “It’s an amazing thing to see – you can just turn around and be surrounded by these wonderful butterflies.
“Here at the Hill House the painted ladies have loved the wildflower area as well as the buddleia bushes and herbaceous borders.
“There’s just so many more than usual in summertime – it’s spectacular to see.”
Sarah Watts, ecologist at Ben Lawers, said: “There have been hundreds of painted lady butterflies on Ben Lawers this summer, given our florally rich hillside.
“We are renowned for our diverse wildflowers – including several species of thistles, which the painted lady feeds on.”
Although it is small and has seemingly flimsy wings, the painted lady can cover up to 100 miles on each day of its epic northward journey.
Its caterpillars feed on various plants, particularly thistles, but also mallows, nettles and some cultivated plants.