Cutting It

The dull brown moth may be dull-looking but as noctuid cutworms they're not.

We spotted this noctuid cutworm, soon to be a dull brown moth, last week on a yarrow in the Storer Gardens at the University of California, Davis.

Noctuids belong to--guess what--the Noctuidae family, which includes moslty the dull-colored moths.

You're likely to see these moths flying around at night, attracted to your porch light.

Another place you can see these moths--as specimens--is the Bohart Museum of Entomology, 1124 Academic Surge, on the UC Davis campus. Directed by Lynn Kimsey, professor and vice chair of the department, the Bohart Museum houses some seven million insect specimens--and a few live ones, such as Madagascar hissing cockroaches. Yes, they give tours. Contact Tabatha Yang at tabyang@ucdavis.edu.

What's really interesting about the noctuids is that they have auditory organs that are capable of detecting frequencies from 3 to more than 100 kilocycles per second.  This can save them from being bat prey.

Bats, you see, emit high-pitched chirps as they fly around at night seeking prey and avoiding obstacles. The chirps bounce back or echo, enabling them to maneuver in complete darkness.

When the dull brown moths hear the chirps, they fold their wings and drop to the ground.

Three kilocycles (3000 cycles) per second is in the top octave of the piano; the average upper limit of hearing in humans is about 15 kilocycles per second. (Source: An Introduction to the Study of Insects by Donald Borror and Dwight DeLong, former entomologists at Ohio State University)