Darker Spotted Straw Moth Caterpillar


Darker Spotted Straw Moth Caterpillar

A year after the Cove Fire consumed over 30,000 acres of the Modoc National Forest, the site along Forest Road 40N11 that Leonard and I are monitoring is rapidly recovering. Over the last year we recorded many mammal, bird, reptile and insect species amid the blackened trees. Trees, shrubs and over forty species of wildflowers are turning the understory green again. It is very encouraging.

During a July visit I found this caterpillar devouring wallflower seedheads and flowers. Not being an entomologist, I am not absolutely certain of my identification. However, I believe this is a darker spotted straw moth caterpillar (Heliothis phloxiphaga).

The adult darker spotted straw moth is yellow-brown or tan with darker markings. The caterpillar is polymorphic and can be green, brown or yellow with mottled dorsal lines and black spots. The caterpillar feeds on the flowers and seedheads of many types of herbaceous plants and is often an agricultural pest.

Darker spotted straw moths are widely distributed in North America from southern Canada to central Mexico. They can be found at low to mid elevations in open grasslands, mountain meadows, sagebrush steppe, open forest and agricultural lands.

In 2015 Sandhya Sekar reported in “Smithsonian” that the serpentine columbine (Aquilegia eximia) has evolved an interesting strategy for protecting its flowers and seedheads against H phloxiphaga caterpillars. The serpentine columbine stems and leaves are sticky. Harmless insects are attracted to the sticky material and die when caught. The dead insects attract spiders with resistance to sticking on the stems and leaves. In addition to eating the dead insects, these spiders eat the adolescent darker spotted straw moth caterpillars feeding on the columbine flowers, buds and seedheads. This sounds like a rather convoluted way to insure the columbine’s reproductive success. But experimentation, which I will not go into here, supports this idea. Fascinating.


This entry was posted in Insects, Moths and tagged , , , . Bookmark the permalink.

2 Responses to Darker Spotted Straw Moth Caterpillar

  1. kfbenjamin says:

    It’s so good to know it is coming back to life.

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