Search Nature Watch

Wednesday, May 14, 2014

Butterfly Buffet

Crimson Patch ovipositing on Flame Acanthus

The very nature of a healthy ecosystem is defined by the interrelationships and dependencies one species has on another, and nowhere is this depicted better than in the world of butterflies and their host plants.

Gulf Fritillary caterpillar on Purple Passionflower

For butterflies, life begins as a tiny round, oval, or cylindrical egg laid on the stem or leaf of a plant. From the egg, a caterpillar or larva emerges, feeding at a steady pace, often shedding its skin several times from its rapidly growing body.  The mature caterpillar then pupates, or encloses its body by forming a chrysalis, in which its tissues are broken down and the adult insect’s structures are formed, transforming itself into a butterfly.

Pipevine Swallowtail chrysalis

While most butterflies nectar or feed on a wide variety of blooming plants, when in their larval stage they are much more restricted.  They are considered to be ‘oligophagous’, or feeding on an especially limited range of typically related food plants, sometimes only one particular species.  Often called host plants, these plants are sought out by female butterflies needing to lay their eggs on or near the plant.  

Giant Swallowtail ovipositing on Wafer Ash

While scientists are still learning how butterflies locate their host plants, many believe it is a combination of chemical smells and taste cues that determine a plant’s appeal to an insect. Butterflies have chemoreceptors at the ends of their antennae and on the bottoms of their feet, which enable them to taste or smell.  They use this sense to locate both nectar and host plants, find mates, identify rivals, and avoid predators.

The dependency of butterflies on specific host plants is among the key factors in restricting the range or distribution of a particular butterfly species, although many species are widespread.  In fact, host plants of certain species may vary across different geographical butterfly populations, and there is still much to learn about these relationships.
In Texas, the astounding diversity of ecological habitats and associated native plants support a wide variety of butterfly species, more than any other state.  In addition, regional specialties can occur, where a species is very limited in range and not typically found in other parts of Texas or sometimes not even elsewhere in the United States.

Malachite, Siproeta stelenes, found in South Texas

Taking the time to learn about host and nectar plants and the butterflies that love them gives us yet another glimpse into the fascinating, ever changing web of life.  It transcends the information we have gathered at the species level and raises it to the inter-species level, providing us with a more connected view of the inner workings of a functional ecosystem.  By applying this knowledge, not only can we more fully appreciate the intricacies of nature, we can create, restore, and nourish the very places where they take place.