A Different Kind of Hosting at CNC by Bill Ward

If you’ve visited the Cibolo Nature Center (CNC), you undoubtedly have met the friendly hosts. These people will direct you to the trails through the four different ecological habitats on the property and point out the other features that draw so many visitors to this special jewel in Boerne’s crown.

Within the new Lende Learning Center at the CNC there is a botanical-garden courtyard, which features woody plants that are native to the upper Cibolo Creek drainage basin. It is an educational display to acquaint the visitor with the surprisingly large variety of shrubs and trees that are locally native.

In that courtyard there is a different kind of hosting going on. Some of the native plants in the botanical garden are hosting certain larvae of butterflies and moths.

It is widely known that the monarch butterfly depends solely on milkweeds to feed its larvae (caterpillars). Perhaps not so well known is that many other butterflies and moths also lay their eggs only on specific host plants. This week in the CNC native-plant garden there are at least three different plants hosting larvae.

The wafer ash or hoptree (Ptelea trifoliata) has caterpillars of the giant swallowtail. This is the largest butterfly seen locally, the big black-and-yellow one. Larvae of this butterfly feed on citrus plants, and wafer ash is a member of the citrus family. In my yard giant swallowtails lay their eggs on another member of the citrus family, prickly ash or toothache tree (Zanthoxylum clava-herculis).

The caterpillar of the giant swallowtail has an interesting protective appearance. Its color pattern makes it look like bird poop. If that is not enough, at some stages the markings on the caterpillar make it appear to have a snake head with well-defined eyes and mouth. When all that fails to deter a possible predator, the caterpillar extrudes orange-red “horns” to frighten off the enemy.

Also in the CNC garden, the spicebush (Lindera benzoin) is hosting larvae of the spicebush swallowtail. This butterfly is a black-and-blue swallowtail with pale-yellow to blue-gray spots along the back margin of the top surface of the wings. It might be mistaken for our common pipevine swallowtail or the black swallowtail. The spicebush butterfly is in the Boerne area because the eastern to southern Edwards Plateau is a western outpost of its spicebush host plant, otherwise a shrub of the Eastern US.

The caterpillar of the spicebush swallowtail hides itself in the protection of a curled leaf, held folded by silky threads the larva secretes. Apparently the spicebush caterpillar sticks out its head occasionally to feed on nearby leaves.

A third larva that is attracting a lot of attention at the CNC lately is the caterpillar of the cecropia moth. This is the largest moth in the US. It has big round spots on the hind wings. On summer nights when we were children in San Antonio, it was common to find those big beautiful moths clinging to a wall When the moth turned with its hind wings upward, we blocked the forewings from view with our hand, and imagined we were looking at an owl face with big peering eyes.

Cecropia moths at the CNC laid their eggs on several Mexican plums (Prunus mexicana), a native of the eastern half of Texas and the Edwards Plateau. Other native trees which host the cecropia moth in this area include willow and big-tooth maple. As the larvae grow, they turn from small yellow caterpillars to giant green ones.

Which native plants you use in your landscaping, determines which butterflies and moths will visit your yard.