25 March 2012

Spring Caterpillars

Spring is the time for many things. It's a real big time for caterpillars, especially those that host on trees and other woody plants. A quiet walk through the neighborhood or the woods this time of year in Central Texas reveals the pitter-patter of caterpillar droppings (frass) falling all over the place.

Gross? No way. I think it's amazing.

It's a good time for caterpillars because leaves are young, tender and just emerging. Most mature leaves are full of defenses, such as waxy coats and chemicals. For an example, just think of the difference between a newly emerging live oak leaf, all bright green and floppy, and one that is about 2 months old, which is dark green and waxy.

Tiny first instar caterpillars have small mouthparts and can't yet handle thick, heavily defended leaves. So many butterflies and moths time their egg-laying to coincide in various ways with the emergence of the new leaves in spring.

Part of having a garden for wildlife is accepting that said wildlife will be eating your garden. For example, I've discovered a new caterpillar that is munching its way through our beautiful stand of heartleaf skullcap (Scutellaria ovata).

I haven't been able to figure out what this one is yet.

These beautiful caterpillars are also new to me this year. They are munching away on our grapevine and all over the Virginia creeper. I've never seen them before.

A couple of weeks ago I kept seeing this beautiful black, day-flying moth with white and orange spots. I tried my damnedest to snap a photo of it, but it flitted away every time.

With a bit of research, I discovered that these caterpillars likely belong to that moth. I think they are  the eight-spotted forester, Alypia octomaculata, and they are having a banner year. (It's possible it is another species of Alypia, but I'll go with this one for now). The caterpillars are all over our grape and Virginia creeper. Since I want the grape, I'm transplanting the moth caterpillars onto the Virginia creeper, which we have plenty of. The adult moths are beautiful, and I'm happy to have them around.

I was ├╝ber-excited on a hike this weekend at the Barton Creek Greenbelt to discover these forest tent caterpillars, Malacosoma disstria. Most people consider these pests, but I think they are completely fascinating, particularly their group foraging behavior.

It's possible these are hosting on a blackgum, Nyssa sylvatica. (I don't know my trees super well and should've collected leaves for later identification.)

These caterpillars move in lines down branches to eat young leaves during the day. Unlike the eastern tent caterpillars, they don't form huge communal tents from silk. Instead, they may rest on a group-built silky mat on a branch at night.

In northern Wisconsin, these caterpillars have enormous outbreaks and drive people crazy. Here in Central Texas, they seem less of a big deal. I didn't even know we had any Malacosoma species here until I found these.


Anonymous said...

The caterpillars in the 2nd photo are all over my grapevine too! There are dozens upon dozens. I've never seen anything like it.

Anonymous said...

The one in the first photo looks like an inch worm.