Painted Lady a sum­mer vis­i­tor all the way from Africa

Wicklow People (West Edition) - - LIFESTYLE -

The Painted Lady is a large and beau­ti­ful but­ter­fly and it’s on the wing to be en­joyed at present. It is not a lo­cal; it’s a mi­grant. It is a sum­mer vis­i­tor to our shores, and it comes all the way from north Africa.

Nei­ther the adults nor their eggs, cater­pil­lars or pu­pae are ca­pa­ble of sur­viv­ing an Ir­ish win­ter. It used to be be­lieved that these warmth-lov­ing an­nual sum­mer vis­i­tors to Ire­land died with the first frosts of au­tumn. It is now known that they don’t die but head back to north Africa when the first au­tumn chills kick in. Ver­ti­cal radar spot­ted swarms of them mi­grat­ing south at an al­ti­tude of some 500m well be­yond the limit of de­tec­tion by our un­aided eyes.

Al­beit that it is a fast and pow­er­ful flier, it is amaz­ing that a but­ter­fly could fly from Africa to Ire­land and turn around and go back again. It is now known that no in­di­vid­ual Painted Lady is ca­pa­ble of achiev­ing that re­mark­able feat; the jour­ney is ac­com­plished over some six gen­er­a­tions.

Painted Ladies in places like Morocco in north Africa set off north on migration and, favourable winds per­mit­ting, cross the Mediter­ranean into Spain. They breed there and the in­di­vid­u­als of the next gen­er­a­tion take up where their par­ents left off and jour­ney north to France. They blindly head north driven by some in­built genetic programmin­g that is still poorly un­der­stood.

The adults of French gen­er­a­tion breed and their off­spring re­sume the jour­ney of their par­ents and grand­par­ents re­lent­lessly fol­low­ing the urge to fly north. They cross the sea and ar­rive in Ire­land to grace our green coun­try­side. The jour­ney is haz­ardous, so num­bers vary from year to year. In a good year, the main in­flux usu­ally oc­curs in May and June.

The adults feed by suck­ing nec­tar from a wide range of gar­den and wild flow­ers. If we have a fine sum­mer the insects breed suc­cess­fully. The cater­pil­lars feed on Com­mon Net­tle, Bur­dock, mal­lows and this­tles and give rise to an Ir­ish gen­er­a­tion of adults in late sum­mer. These in­di­vid­u­als start the long trek back to Africa.

Some­how, prob­a­bly tem­per­a­ture-induced, the in­built genetic programmin­g that com­pelled the but­ter­flies to fly north flips and the Painted Ladies are driven to head south. Suc­ces­sive gen­er­a­tions keep go­ing south un­til they ar­rive back in Morocco. Once back in Africa, their programmin­g flips again and the cycle of migration is per­pet­u­ated.

The Painted Lady is one of our largest and most beau­ti­ful but­ter­flies.

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