Leading ladies

Matthew Oates, friend of Encounter and expert lepidopterist, explains why this summer might be a big one for migrant butterflies (and moths!)

We have been invaded – by insects!  In early May, a sizeable influx of migrant moths, butterflies and some other insects occurred. Further waves arrived during the half-term heatwave. Moth enthusiasts have got very excited, as a whole bevy of unusual moths from the Mediterranean or north Africa have turned up here. 

Most prominent, though, is the painted lady butterfly, which has arrived in numbers and has spread virtually all over the British Isles. This could turn out to be a great painted lady year, to rival the likes of 1996 and 2009 – but everything depends on the weather: in 1980 painted ladies arrived at the start of June, just as a fine spring ended and a rotten summer began, and subsequently failed.   

Most of these recent arrivals are faded ‘grey pilgrims’, who have lost many of their wing scales. They are hungry, and feed up avidly on the likes of Red Valerian.They have already laid a great many eggs here, mainly on thistles.  In hot weather, these eggs generate fresh butterflies within a couple of months – so watch out for home-grown painted ladies from mid-July.  Further waves of incomers may well occur, when the weather peps up. 

Meanwhile, on the moth front, look out for ‘hummers’ – hummingbird hawkmoths, hovering frenetically, probing for nectar with their long tongues.

This has the making of a great year for migrant butterflies, moths, dragonflies and perhaps hoverflies – fifty years on from the great ladybird invasion year of 1976.