Subject: Big Moth
Geographic location of the bug: Carlsbad, California
Date: 08/13/2019
Time: 11:22 PM EDT
Your letter to the bugman: I found this large moth outside my workplace. It made me think of the peppered moths I read about in high school, but I don’t know if they’d be found in Southern California
How you want your letter signed: Thomas
Dear Thomas,
We don’t know what “peppered moths” are, but this is a Rustic Sphinx.
The peppered moth, Biston butalria, is an species found in England that provided an early test of natural selection. It has two color forms. The dark colored form increased in frequency during the industrial revolution when pollution made it harder to see on sooty bark. As pollution was abated, the light form made a comeback. I expect Thomas had read about this species.
Thanks Jim,
You jogged Daniel’s memory as he recalls reading about this moth in the 1960s. Ask a Biologist has a nice explanation.