Introduction
Cave cricket (Rhaphidophoroidea Walker, 1869) as one of the oldest species of Orthoptera, are widely distributed all over the world. It considered to be the basis of the six families and one of the oldest taxa in the Tettigoniidea clade (Song et al ., 2020). They are gregarious and typical apterous groups, which includes 10 subfamilies and 87 genera (including 1 fossil subfamily and 2 fossil genera). They mainly inhabit in dry leaves, stone crevices, caves and other dark humid environments, therefore their speciation as well as population structure have relatively strong dependence on geographical isolation (Juanet al ., 2010).
Dating estimates indicated that Rhaphidophoridae originated in the Cretaceous period during the Mesozoic era with the ancestral area located both in the northern and southern hemisphere. The current distribution of Rhaphidophoridae might be explained by a combination of both dispersal and vicariance events occurred especially in the ancestral populations. The radiation of Rhaphidophoridae started within the Pangaea, where the ancestor of Rhaphidophoridae occurred throughout an ancestral area including Australia, North America, and the Mediterranean region. The opening of the Atlantic Ocean promoted the divergence of North American and Mediterranean lineages while the differentiation of the southern lineages, spread from Australia, appears to be related to the fragmentation of Gondwana land (Allegrucci & Sbordoni, 2019). The Indian subcontinent (including India and southeast Asian countries north of the Indian river) was originally part of Gondwana continent, and the initial collision between it and Eurasia probably began in the late cretaceous, and the main collision period occurred around 55–50Ma, which coincided with the isolation of the Aemodogryllinae and Rhaphidophorinae. After the collision of the Indian subcontinent and the Eurasian continent, insects from the two continents met again here, which also provided rich raw material for later Oriental insect species (Jia, 2010).
China straddles Palaearctic and Oriental realm, occupies an important biogeographical position in the world. Recent years, many papers on molecular biogeography of insects have been carried out in China. Based on the phylogenetic relation and distribution of four grasshopper genera of Catantopidae from the south of China, ten areas of endemism have been recognized (Xu et al ., 2003). The order of the formation of the 10 distribution areas of these insects was as follows: southern Yunnan and Loess Plateau, Hainan Island, eastern Mountain and Taiwan Island; The Yunnan-Guizhou plateau, northern Yunnan and Qinling-Daba mountains formed at the same time, while the southern China and jiangnan hilly region formed the last. Wang et al . (2020) determined the phylotaxonomic relationship and differentiation time of the genusSinocyrtaspis endemic to China. Based on the geographic dynamics and climatological data of its ancestors, it was concluded that the centres of origin of Sinocyrtaspis were Hunan and north-east Guangxi. Their ancestors had two dispersal routes ending in Jiangxi and Zhejiang, after the cold period of the Miocene, some of the ancestral species remained in Guizhou while others moved out. And as a response to climate change, species altered distribution areas by moving along altitude gradients in mountain regions, whereas the anthropogenic global warming trend has promoted some species moving to high-latitude areas or caused population differentiation. However, there is still a lack of biogeographic research on the widely distributed Oriental species, especially the Rhaphidophoridae in Oriental realm.
China is the main distribution area of Rhaphidophorinae Walker, 1869 and Aemodogryllinae Jacobson, 1905. Diestramima Storozhenko, 1990 is (Rhaphidophoroidea: Aemodogryllinae, Kevan, 1977) widely distributed in the Oriental realm of China (with 70% of known species) and adjacent countries. Their range is limited to the Oriental realm (tropical and subtropical mountainous hilly areas), because they usually choose wide shrub leaves as mating sites. All species of this genus has long protuberances on the seventh abdominal tergite, and the shape of the protuberances is significantly different among different species. The morphological classification system and the relationship between species are relatively clear. Therefore, Diestramima is a suitable candidate group for studying the speciation and diversity patterns of Oriental realm in China and the corresponding geological changes.