Researchers combined results from sophisticated
radar with thousands of sightings reported by volunteers across Europe.
The results revealed that as the summer ends, millions of painted lady
butterflies migrate south, mostly flying at an altitude of more than
1,600 feet (500 m) —therefore hardly ever seen by humans. The
butterflies wait for favorable winds, which they ride at an average
speed of 28 miles per hour (45 km/ h) on the long trip to Africa.
Their annual migration is up to 9,300 miles (15,000 km) long, beginning
from as far north as the fringes of the Arctic and terminating as far
south as tropical West Africa. The trip is almost double that of the
North American monarch butterfly. It takes six successive generations of
painted ladies to complete the round-trip.
“This tiny creature weighing less than a gram
[0.04 oz] with a brain the size of a pin head and no opportunity to
learn from older, experienced individuals, undertakes an epic
intercontinental migration,” states Richard Fox, surveys manager at
Butterfly Conservation. This insect was “once thought to be blindly led,
at the mercy of the wind, into an evolutionary dead end in the lethal
British winter,” Fox adds.
Yet this study “has shown Painted Ladies to
be sophisticated travellers.”...:-)