North Simpson Farm Restoration Site: Halloween Caterpillars

By Kendall Kroesen, Habitats Program Manager

For the month of October—leading up to Halloween—the current work area at the North Simpson Farm habitat restoration site has been a ghoulish place!

There has been an impressive infestation by salt marsh caterpillars. In some areas, particularly among the weeds they were eating, there were an estimated 5 caterpillars per square foot. There must have been tens of thousands of them or more across the site.

These insects come in a variety of colors—most notably black and bright orange! They are fuzzy and actually pretty cute for a caterpillar.

As the temperature went up in the morning they would seek shade and sometimes become quite concentrated under our vehicles.

They would also fall into the planting holes we dug. So many were ambling across the ground and falling into the holes that at one point I scooped them up and Rodd Lancaster took this photo.

Salt marsh caterpillars are crop pests, so perhaps it’s not surprising that we have seen this in the Avra Valley in an agricultural area.

As November started the number of caterpillars is way down and we imagine they are pupating. One of these days we’re expecting to see a lot of white moths—the adult form of the salt marsh caterpillar.

More about salt marsh caterpillars can be found at http://entnemdept.ufl.edu/creatures/veg/leaf/saltmarsh_caterpillar.htm.