Luminous yellow caterpillar sparks interest
An unfamiliar luminous yellow caterpillar nudging across a garden path brought us to our feet from our patio chairs to investigate.
We hadn’t seen many caterpillars this season. Our family of Texas spiny lizards and a horde of hungry birds have pretty much taken care of our insect population.
This striking 3-inch yellow fellow with green stripes throughout was worthy of further study.
We lifted the visitor and placed him in a small box for close inspection. I ran inside to get the butterfly field guide because we couldn’t identify him.
Of course, the guide was nowhere to be found. Finally, I ran outside with the guide in hand to identify his family and hopefully, his host plant on which he had been feeding. We couldn’t find a match either because the pictures were not clear or none looked exactly like our specimen.
Placed back on the path, the caterpillar made a bee-line to and up the Mexican mint marigold.
Our first thought was that this sweet-smelling sun herb was its host plant. We knew that its fall golden blossoms were a good nectar source for butterflies, but was it also a host plant?
Each butterfly species has one to several larval food plants on which it lays eggs. The larvae will then consume that plant before developing a chrysalis from where the adult will eventually emerge.
Some examples of larval food plants include dill for black swallowtails, pipevines for pipevine swallowtails, mistletoe for great purple hairstreaks, passion vines for gulf fritillaries, Texas thistle for painted ladies and hackberry trees for snouts.
One of the more interesting is the yucca giant-skipper that lays its eggs on the tip of yucca plants. The eggs hatch within a few days and the larvae build a silk “nest” among the leaf tips where the larvae thrives.
Eventually, they tunnel into the yucca roots and construct a dung-covered silk chimney-like tube near the yucca base where they hibernate.
In spring they emerge from the silken tube as an adult giant-skipper. These large skippers fly only during springtime but never feed on nectar; males obtain nutrients by sipping mud.
Our yellow caterpillar wasn’t munching on the Mexican mint marigold and all the leaves seemed intact.
His behavior gave us all the indications that he was ready to attach himself to a branch and begin his final metamorphosis into a butterfly.
So, what was the identity of this butterfly and what was his host plant? Over the years, we have noticed that several butterflies are attracted to plants that have like-colored flowers. It’s not anything scientific mind you, just an observation.
We started to survey all the surrounding plants with similar-colored blooms; although we have noted that some caterpillars do travel more than 40 feet from their host plant to affix themselves for their final stage.
However, we didn’t have to go far in our plant survey. Less than nine feet away from the Mexican mint marigold was a flowering senna plant with its bright-yellow clusters of five-petal flowers. The flowering senna, also called Argentine senna, makes a great shrub or mini-tree reaching 6-8 feet tall and wide; although, it is not very cold tolerant.
Sennas, formerly included with the cassia family, are a large genus that includes over 250 species of flowering plants native throughout the tropics, with a small number of species reaching into southern regions of the country.
Among the most-readily known sennas in this region is the candlestick tree, an old-fashioned, easily grown plant which can reach 15 feet in height, the two-leaved senna, and Lindheimer’s senna, a native of the Edwards Plateau and the Trans-Pecos that grows to 4 feet and blooms in part shade from August to September.
With the host plant identified, the mystery was solved. The wandering caterpillar was one of the cloudless sulphurs, golden yellow butterflies.
Delgado is a Texas Master Naturalist. She and Scott are members of the Highland Lakes Birding and Wildflower Society and the National Audubon Society. E-mail them at viva.dana@yahoo.com.