Butterfly Biodiversity on Isla Socorro, Mexico, with Comments on the Taxonomic Status of the Endemic Hairstreak Strymon istapa socorroica (Lycaenidae)

Abstract

Lepidoptera biodiversity on Isla Socorro, a small volcanic island in the Islas Revillagigedo Archipelago located off the west coast of Mexico, is poorly known. The native flora of this island was severely degraded for more than 140 years of overgrazing by introduced feral sheep. Sheep were successfully eradicated in 2012, and the habitat is now beginning to recover. The few published records of the butterfly fauna (eight species), however, were obtained more than 30 years ago, well before sheep removal. Here we provide results of a recent survey of the Lepidoptera based on collecting and observation of adult butterflies during November, 2019. We confirmed that five of the eight previously recorded species are still present, and in addition show that Pyrisitia lisa centralis (Pieridae) has now become established. We also analyzed DNA barcodes from the endemic hairstreak Strymon istapa socorroica (Lycaenidae) that support maintaining its subspecies status. Whether the three previously recorded species not seen by us have been extirpated will require more exhaustive sampling.