Small tortoiseshell butterfly fails to thrive in summer heat
NUMBERS OF one of the UK’s best known garden butterflies have plummeted this summer despite the record-breaking hot weather, a study has revealed.
The small tortoiseshell suffered its worst summer in the history of the Big Butterfly Count with sightings falling by 32 per cent compared to last year.
Just 23,000 of the butterflies were counted by participants across the UK during the threeweek recording period between July 20 and August 12, which coincided with the joint hottest summer on record.
The population of the once common and widespread small tortoiseshell has reduced by 75 per cent since the 1970s and there are growing concerns among scientists for the butterfly’s longterm future. Reasons for the decline are being investigated, with climate change, pollution and parasites all possible culprits.
The hot, dry weather experienced across the UK this summer should have helped most butterflies, but the small tortoiseshell was not the only species to suffer a slump.
Populations of red admiral and comma were well down, 73 per cent and 40 per cent respectively compared to the high numbers seen in the same period last year, and gatekeeper fell by 54 per cent. Other common species were seen in improved numbers.
Butterfly Conservation’s associate director of recording and research, Richard Fox, said: “The ongoing decline of small tortoiseshell is clearly a concern, especially given the generally good weather this summer, but it was good to see the high numbers of whites and common blue being reported across the UK.”