Evolutionary Dynamics of Behavioral Divergence among Populations of the Hawaiian Cave-dwelling Planthopper Oliarus polyphemus (Homoptera: Fulgoroidea: Cixiidae)

摘要

The cixiid genus Oliarus has undergone extensive adaptive radiationon the Hawaiian Islands, with 80 described endemic species descendingfrom an initial successful colonization by a single ancestral species. In HawaiianOliarus, however, adaptive radiation is not restricted to surface habitats. Severalevolutionary lines have invaded lava tubes independently on the islands ofMolokai, Maui, and Hawaii. Populations of one of the cave invasions onthe island of Hawaii, the blind, flightless, and pigmentless species Oliaruspolyphemus Fennah, have been found in numerous lava tubes within four ofthe five volcanoes on the island. Recent investigations on mating behavior,especially the analysis of the substrate-borne courtship signals of several O. polyphemus populations, revealed a high degree of divergence: the signals of allseven cave populations studied differ significantly. Because these signals serveformate recognition within species of planthoppers, we regard the O.polyphemuspopulations studied to be reproductively isolated (i.e., representing separatebiological species). Hypotheses to explain this high degree of divergence amongO. polyphemus populations are discussed.