Butterfly master of camouflage suffers worst year as numbers fall

● Population of Grayling drops 61 per cent north of the Border

One of Scotland’s best hidden butterflies suffered its worst year on record last year, according to a major scientific survey published today.

The Grayling - a master of camouflage against a background of rocks or tree trunks - dropped by 61 per cent north of the Border last year.

The largest of the brown butterflies, with a wingspan of up to 60mm, the Grayling has now declined by 82 per cent since 1990, making it a priority species for conservation.

Thelargewhite,alsoknown as the “cabbage white”, also suffered its worst ever year in Scotland after the population fell by 13 per cent compared to 2015 - a decline of 25 per cent since 1979.

The dramatic declines are highlighted in the annual UK Butterfly Monitoring Scheme (UKBMS), which reveals species across the UK suffered their fourth worst year on record in 2016.

Some 40 of the 57 species studied - over two thirds - suffered declines according to the scheme led by the charity Butterfly Conservation (BC) and the Centre for Ecology & Hydrology (CEH).

A mild winter followed by a cold spring are thought to have contributed to adverse conditions that saw both rare and widespread species struggle

0 The decline in the Grayling could be partly because of a mild winter and cold spring despite a warm and dry summer in many parts of the UK that would usually be expected to help the insects thrive.

Across the UK, six species had their worst year on record, including the already extremely rare Heath Fritillary - which does not occur at all in Scotland - for the second year in a row. The Grizzled Skipper, Wall, Grayling, White-letter Hairstreak and White Admiral also recorded their worst ever year.

Research suggests that the UK’S increasingly mild winters are having a negative effect on butterflies as they may lead to increased disease, predation or disruption of overwintering behaviour.

Cold springs can also cause problems by reducing or delaying emergence leading to shortened lifespans.

Some species bucked the trend, however. In Scotland, the Small Pearl-bordered Fritillary recorded its best year on record, with numbers up by 109 per cent compared to 2015.