Monday, May 21, 2012
THE AMERICAN EMPIRE
Asterocampa celtis, the Hackberry Emperor and Asterocampa clyton, the Tawny Emperor are just as interesting as the European Apaturas and thus it’s possible to waste an equal amount of time sitting around watching them. In general they are smaller and faster. You get the impression that they are tougher too, dashing around all over the place, the males aggressively defending their patch against allcomers. Magic. Their hostplants are Celtis sp. the hackberries and the larvae are similar to Apatura larvae but are smaller and brown in colour. If you find a Hackberry tree, chances are you’ll see one or other of these little brutes. They must have a complicated parasite relationship because they can become over populated and defoliate an isolated stand of Hackberry.
A. celtis is double brooded in the north and A. clyton has a single flight, so it’s rare to find them on the wing at the same time, but it can happen. It’s the females that are a rare sight. Always larger than the males, they hide away in the tree tops, decending rarely to damp earth for moisture but vary seldom anywhere where you can see them. The males can be attracted to fruit, pee or damp soil. In fact a blue shirt seems to be an equal draw and if it’s a hot day (And chances are, it is!) a sweaty blue shirt will bring them down fearlessly. I’ve seen them chase Blue Jays, even a Goshawk, but to see these little butterflies aggresively chase a full size American pickup truck off a bridge is quite something.
I used to take part in the North American Butterfly Association butterfly counts, a sort of one day manic competitive butterfly census within a limited 25 mile radius. Well, one year we were getting close to a record number of species and so the magic pee under a hackberry tree was employed to a nice fresh Tawny Emperor to the list!