Wednesday, August 28, 2013

Summer Flutters By

Common Wood Nymph (c) John Ahsley
An adult Common Wood Nymph nectars on yarrow flowers
For being such showy animals, our summer butterflies also have a few secrets that most of us are unaware of. Common Wood Nymphs (Cercyonis pegala) are a brownish butterfly of wet, grassy habitats. Here at the end of the road, they are easily the most numerous butterfly species in a nearby field of invasive knapweed that is the legacy of a logging operation many years ago.

One of the Wood Nymph's most intriguing behaviors occurs during courtship. Males pursue females in flight and, if interested, the larger female will land and remain motionless with her wings closed. The smaller male lands in front of her and demonstrates his fitness by fluttering his wings and repeatedly head-butting the object of his affection. This might cause some females to say, "Not tonight I have a headache." But if she's receptive to this behavior (i.e., she doesn't leave), he will step beside her and flutter his wings ever-so-gently while bending his abdomen to hers and passing along his head-butting genes.

Afterwards, another interesting little behavior arrives later that summer. The Wood Nymph egg hatches into a greenish caterpillar that does not eat for its first 6-8 months. Instead the slender caterpillar hibernates until spring, when it will finally begin eating and eventually pupate into an adult in early summer.

Butterfly secrets are just interesting, normal butterfly behaviors that you haven't yet noticed.