Butterfly tree

I’ve had a creepy curiosity in my yard all summer that I finally took some time to examine this week. About a month ago I noticed Red Admiral (Vanessa atalanta) butterflies in the front corner of the yard along the edge of my front field and the neighbor’s soybeans. I know from childhood that they are territorial and bold around people and also that you can find them in the same place every evening. Last time I mowed I got strafed by butterflies there, so I figured I’d go look around when I had time.

When I went out in the evening, I found a group of 5-10 butterflies, mostly anglewings--Commas (Polygonia comma) and Question Marks (P. interrogationis), but also a Red Admiral and a hackberry butterfly (Asterocampa celtis) flying around a ragged, half-defoliated slippery elm (Ulmus rubra Muhl.) sapling in that corner. The butterflies would fly around in groups and then occasionally land on the tree. Elm species are host plants for the anglewing caterpillars, but not the Red Admiral. All of these species are territorial as adults and the adults feed on tree sap as well as rotting fruit and dung. As I watched, I noticed bees and flies hanging around the trunk too. A few birds flew in and out of what was left of the canopy--I think they were female indigo buntings.

Question Mark Butterfly

Hackberry Butterfly

Once I got around to the soybean side of the tree where I could get close look, it was clearly a sapfest. Butterflies swooped in and out, and around my head, a troop of horseflies swarmed on the trunk for minute, then disappeared, and a bald-faced hornet made an appearance. There was even an adult cicada in the branches. There was a lot of activity and buzzing around--there was a definite “creep factor” at work here!

Horseflies (Tabanus sp.). Only the female horsefly drinks blood, so these are probably males.

Cicada adult