The Nature Writers of Texas

The best nature writing from the newspaper, magazine, blog and book authors of the Lone Star State . . .

Thursday, September 18, 2008

Snout Butterflies are Flying Once Again
by Ro Wauer

On a recent trip from Big Bend National Park, we encountered thousands of snouts flying across the highway, especially between Del Rio and San Antonio. The vehicle was plastered with snouts, almost so many on our window that it made it dangerous to see ahead. It was necessary to take our vehicle into town to get it washed before those bugs damaged the paint. And now the snouts are beginning to increase in our area, flying every which way.

Snout butterflies occur throughout Texas as well as west to southern California, east to central New England, and south into Mexico. They normally frequent woodland edges and stream courses and utilize hackberry plants to lay their pale green eggs. The tiny larvae, or caterpillars, which are dark green with yellow stripes, feed on hackberry leaves. They pupate before overwintering as adults in protected areas.

Some years they become super abundant. Raymond Neck, author of the 1996 book, “The Field Guide to Butterflies of Texas,” explains: “Certain climatic conditions, such as severe drought followed by heavy rains over a large area is southern Texas, produce massive amounts of leaves of foodplants. The leaf production allows a major buildup in population numbers of larvae and, subsequently, adults. The new generation of adults emerges at a time when the foodplants have been stripped of most of their leaves. The lack of leaves and the dense concentrations of adults trigger a migration involving masses of butterflies that easily number in the hundreds of thousands and even in the millions of individuals.” September 2008 is one of those periods.

Snout butterflies, more appropriately known as American snouts (Libytheana carinenta), are little butterflies, about one inch in length and with a wingspan of almost two inches. In flight they appear to be multicolored with brown, black and cream-colored wings. When perched with open wings their colors are obvious, as well as their distinct shape, including a long snout and square-tipped wings. Most often they perch with folded wings, perpendicular on a branch or on another surface, showing their gray to black to brown undersides. Their long snout is obvious. This unique feature makes them look very much like a leaf or twig and is said to have evolved in this butterfly family to provide them with wonderful camouflage.

Snouts truly are remarkable creatures, part of our native wildlife. However, there are times when they become so numerous along our roadways that they are less marvelous and become more of a pest.

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