Bon Voyage indeed when we consider some of Ed's Lincolnshire Painted Ladies' reverse migration challenges : - using a solar compass, to navigate South initially to the UK coast, flying at high altitude by day or night
-to cross the English Channel
- to traverse France/Spain
- to cross the Mediterranean
- to arrive at the final destination of the desert fringe areas of North Africa to breed.
All of this to be achieved by an insect weighing less than a gram with a brain the size of a pinhead. As it has no hibernating stage in its life cycle and its caterpillar perishes at temperatures lower than about 5C, there is probably no place in Europe where the species is permanently resident. Consequently, in the UK, we depend on immigrant PLs to replenish stocks every spring.
The Painted Lady's transition cycle usually lasts about 4 weeks : egg - caterpillar - chrysalis into adult. The butterflies arriving back in North Africa in the autumn will be several generations removed from their ancestors which left in early spring to fly North. Some Painted Ladies reach the Arctic Circle and the successive generations achieve a round trip from tropical Africa of many thousands of miles and one that is almost double the length of the famous migrations undertaken by Monarch butterflies in their USA/Canada - Mexico - Canada/USA round trip.
Let's hope 2017 will be a 'Painted Lady year' with literally many millions of immigrant butterflies arriving in the UK (as in 1996 and 2009).
Freddy
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