With the temperature in the high 80s yesterday, I may have overdone it on my mountain bike. I climbed hill after hill giddy with the adrenaline of the previous downhill thrill. Today, my legs feel like they are filled with lead. Athletics have a way of showing your age, but I was heartened to learn that I wasn’t alone. It turns out that butterflies have the same age old problem.
In 2009 scientists in Sweden reported that the flight endurance of a small butterfly called the Green-veined White decreased with age. The Green-veined White (Pieris napi) is found across Europe and Asia, including the Indian subcontinent. Some scientists believe that the Mustard White, a woodland dependent species found here in the Northeast, is a subspecies of Pieris napi while most now align it as its own species, Pieris oleracea. Either way, they are very closely related and look quite alike.
How do you test endurance in a butterfly? The scientists released individual butterflies 6 feet in the air and when they landed, they were prodded to fly again and again, and yet again until they were too exhausted to fly. A simple stopwatch yielded the total flight time. They tested three age groups that were raised in captivity. One group was kept in cages for 10 days and another was kept in the cages for 5 days. The third group was 1-day-old butterflies newly emerged from the chrysalis and roaring to go. These butterflies probably only have an average adult life span of about two weeks.
It didn’t matter if they were male or female, young and middle-aged butterflies performed about the same. But by the time the butterflies were 10 days old they were over the athletic hill. I guess I must be about 8 in butterfly age. I just can’t keep up with the newly emerged anymore. I’ll just have to ride more wisely.