Phylogenetic relationships and relictualism of rock-crawlers (Grylloblattodea: Grylloblattidae) in cave and mountain habitats of Korea

Abstract

Rock-crawlers (Grylloblattodea: Grylloblattidae) in northeastern Asia are low-vagility insects that are restricted to cool temperate forests and mountainous regions. Morphologically distinguishable species are similar ecologically and show narrow endemism and a patchy distribution. As a result, grylloblattids are hypothesized to be relict species that have persisted in situ over long periods of climatic and geological change (Storozhenko and Oliger 1984). We investigate whether the diversification pattern of Asian grylloblattids reflects long-term persistence and divergence due to geological events, or more recent diversification in response to climatic change. Using multilocus genetic data, we examine the phylogenetic relationship to other Asian Grylloblattidae and the geographic pattern of diversification of Korean rock-crawlers, Galloisiana Caudell & King (1924) and Namkungia Storozhenko & Park (2002). Our analysis reveals a monophyletic grouping of Korean species, with multiple cryptic lineages and restricted geographical distributions. Based on genetic data, Korean species are closely related to Japanese Galloisiana. Using a Bayesian relaxed clock model calibrated with a mitochondrial substitution rate, the age of the most recent common ancestor of the Korean-Japanese lineage is estimated within the Miocene epoch. This provides evidence for a diversification event closely tied to the geological events separating the Japanese archipelago from the Korean peninsula. © 2011 Entomological Society of America.