|Bruce Spanworm - Operophtera bruceata|
This is the third species of moth to show up on the garage at Westwood Hills Nature Center late in the fall. It's another cold weather specialist, like the Fall Cankerworm Moth and the Linden Looper Moth, both featured in previous posts. And like those other two species of moth, the females of the Bruce Spanworm are flightless. Presumably the reason for flightless females is a trade off; being able to fly in cold weather for an insect takes a lot of energy and producing eggs takes a lot of energy, so something had to give, so to speak.
By the way the counts were anywhere from 30 moths to 100 (total of all three species). I think there were probably about 60 moths, the most yet this fall.