Rare Butterfly At Hagerman

Text and photos by Laurie Sheppard

One of the ongoing projects of the Butterfly Garden Docents is to identify every species of butterfly that lives on or visits Hagerman National Wildlife Refuge. The Butterfly Garden is commonly visited by a wide variety of butterfly species. Some previously rarely seen butterflies have become common sightings because of their attraction to the garden’s nectar and host plants. However, volunteers frequently find new species in places other than the garden. This is the story of a butterfly that is unlikely to ever visit the Butterfly Garden. It favors a specific habitat and rarely travels far from its “birthplace”.

Driving down Sandy Point Road last spring, I saw many yellow flowers along the roadside and in the open fields around the oil pumpers. There were several different types of butterflies hovering around, so I stopped to check what species were there. When I looked closely, I found a butterfly I had never seen before clinging to the stalk of the plant. It was a Frosted Elfin and we logged it as a new species on the refuge. In November, when we were reviewing the new species for the year, we discovered this little butterfly is the subject of great concern due to its diminishing numbers and actual disappearance from large parts of its historic range.

Frosted Elfin

Historical records show that the Frosted Elfin was found throughout the eastern half of Texas. However, in the past decade, only three sightings, including the one at Hagerman had been made public, adding to the uncertainty over the butterfly’s status. It is speculated that loss of habitat is the greatest threat to this species. The North American Butterfly Association received a Texas Conservation License Plate Wildlife Diversity Grant to create a “state status assessment of the Frosted Elfin”. Volunteer Texas Master Naturalists are participating in this effort with the cooperation and assistance of the Butterfly Garden Docents and refuge staff.

The host plant for the Frosted Elfin in Texas is any of three varieties of Wild Indigo. Yellow Wild Indigo (Baptisia sphaerocarpa) grows abundantly in the Sandy Unit of the refuge, so that was our target area for investigation. The plants began to emerge in early March but were obscured by last year’s grasses and refuse. We checked the area frequently and eventually, could see how widespread the plants are. They are now forming buds and will soon be blooming. Finally, on March 21, we saw our first Frosted Elfins of 2018.

The Frosted Elfins are currently mating and placing their eggs on or near the plants’ flower buds. As the plants develop and bloom, the eggs will hatch and tiny Frosted Elfin caterpillars will feed and grow. The caterpillars will be less than half an inch long when they pupate. Each of this year’s caterpillars will begin metamorphosis but remain in its chrysalis until emerging as an adult butterfly next spring. Frosted Elfins have only one brood per year.

So far this year, we’ve identified at least fifteen adult butterflies while looking only at the edges of the fields of Wild Indigo. It’s likely there are more that haven’t been seen. These butterflies may have escaped notice at Hagerman because of their small size (a closed wingspan of 1/2"), secretive low-flying behavior, and similarity to other dark butterflies also emerging in early spring. Now that we know where they are, though, the habitat can be protected to secure these threatened butterflies.