So it was without a lot of hope that I decided to recover — after one particularly grueling hike day into the heart of the Chisos Mountains tracking the Colima Warbler — by driving down the following day to the relatively flat desert along the Rio Grande in search of one of North America’s most recently described butterflies. I was after Big Bend Scrub-hairstreak, named by Nick Grishin and Christopher Durden in 2012 from an area near Rio Grande Village called Boquillas Canyon in the far western reach of the national park [Grishin, N.V. & C.J. Durden. 2012. New bromeliad-feeding Strymon species from Big Bend National Park, Texas USA and its vicinity (Lycaenicdae: Theclinae). Journal of the Lepidopterists’ Society 66(2): 81–110.] This new species, Strymon solitario, the Big Bend Scrub-hairstreak, has a limited distribution in exceptionally arid, rocky habitats where one can find its food plant, Texas false agave, Hechtia texensis.
Imagine my surprise, then, when after walking out the nature trail at Rio Grande Village and climbing up to the top of a limestone promontory overlooking the river, that I encountered veritable swarms of hairstreaks hill-topping on the summit. I’d seen few lycaenids at all in Big Bend to this point, and none of them hairstreaks, so I was pleasantly surprised to find them landing on my cap, my hand, my camera — and on the fading stalks of Hechtia that were all around! Sure enough, when I got back to the computer that night and compared the photos with the illustrations in Grishin & Durden and elsewhere online, looks like this is another population of Big Bend Scrub-hairstreak.
The species epithet solitario, by the way, doesn’t have anything to do with its gregariousness or lack thereof. It’s named after El Solitario, a geologic formation looming over the landscape in the neighboring Big Bend Ranch State Park, where specimens also were collected.