From the dark side of paradise: a new natural replication of cave planthopper evolution from Hawaiian lava tubes (Hemiptera: Fulgoromorpha: Cixiidae)

The Hawaiian Islands are known to harbour a rich and diverse fauna of troglobionts (obligate subterranean species). To date, 74 obligate cavernicolous arthropod species have been documented from across the main Hawaiian islands, the majority of which were from Hawaiʻi Island, and mostly from lava tubes of Kilauea volcano, the youngest volcano on the island. A recent bioinventory of the Kipuka Kanohina lava tube system on the south-western side of Mauna Loa volcano revealed the existence of previously unknown cave-adapted species. Among them is the first cave-adapted species of the planthopper genus Iolania, Iolania frankanstonei Hoch & Porter sp. nov. Morphological and molecular data suggest that the species is closely related to the epigean (i.e. surface-dwelling) species Iolania perkinsi, which occurs in surface environments on Hawaiʻi Island. Thus, parapatric speciation is assumed, further corroborating the assumption that adaptive shifts are the major evolutionary patterns underlying the evolution of troglobionts on young oceanic islands.