I am a huge fan of the American novelist Barbara Kingsolver who effortlessly melds natural science and fiction in visionary novels like Unsheltered.
In Flight Behaviour, the mysterious apparition of mass kaleidoscopes of orange monarch butterflies choosing to overwinter in the cool climes of the Appalachians instead of the warm south conjures up the omnipresent spectre of climate change.
In real life, this plucky butterfly’s annual migration, incredibly, is surpassed by that of the painted lady which flies almost double the length of the monarch in “an extraordinary 7500-mile round trip from tropical Africa to the Arctic Circle every year.”
We are, apparently, in the midst of a ‘painted lady summer’. Unusually high numbers were seen across Europe over the spring. Large swarms were then spotted over the UK and Ireland in July, touching down wherever there are thistles to sustain the next generation of caterpillars.
Painted ladies can travel up to 100 miles a day when they migrate. Their annual pilgrimage starts in Africa in April when they head north and, with a life cycle of just 5-8 weeks, it can take up to six generations to complete migration.
Sometimes known in North America as the cosmopolitan, this orange, white and black butterfly is thought to benefit from a baby boomer effect once every ten years. So, before this year, 2009 was the last time millions arrived in the UK en masse – around 11 million in total. According to the charity Butterfly Conservation, more than half of all sightings across a ten year period came in 2009 alone.
Survival of the f(l)ittest
Other UK butterflies are also thriving. Last year’s extended hot summer saw the common blue population increase by 104% in comparison with the previous year. Don’t celebrate just yet though as the stately red admiral – always my favourite flutterby as a child – dropped by a whopping 75% in 2018.
Butterflies – the most ethereal of our winged creatures – exhibit astonishing ferocity in their quest to survive. The male purple emperor – the doyen of Lepidoptera in this country – likes to flitter high up in the canopy of oak woods but behaves so aggressively when attempting to mate that it has been known to chase off buzzards.
Then there’s the mind-blowing fact that the butterfly actually arranges its life cycle to avoid timetable clashes! Each species depends on a narrow range of plants as fodder for their caterpillars. In the case of the chalkhill blue, for example, it hatches out six weeks after its close relative the Adonis blue as both depend on the horseshoe vetch for survival.
By this point the Adonis blue is a chrysalis and the chalkhill blue is free to perform its very best impression of the very hungry caterpillar… Evolution in all its glory.