New dung beetle species closely related to Russian beetle reveals complicated components of Taiwanese insect fauna
A new species of dung beetle was the first to be given a scientific name in honor of Taiwan's highest mountain peak after its discovery by an NTU researcher in the NTU Experimental Forest near Mount Jade. Named Sinodiapterna yushana after the mountain's Mandarin name, Yushan, the newly classified beetle was presented to the world for the first time in the prestigious international journal Zootaxa in late 2017.
Assistant Research Fellow Chun-Lin Li of the NTU Experimental Forest captured two pairs of adult specimens of the beetle as part of an Experimental Forest research project surveying altitudinal patterns of the species richness and abundance of dung beetles in forest areas managed by the Experimental Forest near Mount Jade. Li conducted his survey by setting up fixed, time-controlled specimen collection devices along elevation gradients ranging from 800 to 2,800 m, and the study sites were located within the primeval forests located in the Heshe Forest area of the Shalihsien River Valley.
While inspecting one of his traps established in a mid-elevation (1,600 m) forest, Li found several dung beetles that he had never seen before and noticed that the scutellum of this species was especially long. He then realized that this feature, in combination with other features, could be used to identify the beetle species. Li teamed up with Professor Ping-Shih Yang of the Department of Entomology to perform a detailed comparison against available information and specimens. Based on their work, the researchers concluded that the beetle was indeed a member of the subfamily Aphodiinae within the scarab beetle family Scarabaeidae and that it was nearly unknown to science.
Further comparisons with known Asian aphodiine dung beetles led Li and his coauthors to conclude that the unusual species should belong to the genus Sinodiapterna Dellacasa, 1986, whose distribution is restricted to the eastern Palaearctic Region (Japan, Korea, Northeast China and the Russian Far East). Referring to the five known species in the genus, Li and his coauthors found that the species most closely related to Li's Yushan dung beetle is an extremely rare beetle within the genus (i.e., Sinodiapterna gorodinskiyi) that is represented by a single female specimen. Accordingly, both species constitute a particular species group within the genus. However, while S. yushana is found in hardwood forests, S. gorodinskiyi inhabits coniferous forests 2,000 km to the north of Taiwan in Primorskiy Kray in the Russian Far East. This enormous geographical distance is all the more remarkable because it spans vast differences in climate ranging from subtropical latitudes to a cold northern temperate zone.
Based on scientific data accumulated for over a century, the insect fauna in Taiwan's mid-elevation mountain areas are generally considered to share a much higher zoogeographical association with insect species in southern and western China, the northern areas of the Southeast Asian mainland, and the eastern Himalayas. Along with its Russian cousin, S. yushana occupies a rather unique position among Taiwan's insect fauna.
Reference
Li, C., Yang, P., and Wang, C. (2017). The genus Sinodiapterna Dellacasa (Coleoptera: Scarabaeidae: Aphodiinae) in Taiwan. Zootaxa, 4320(1), 68–80. DOI:10.11646/zootaxa.4320.1.4.
Chun-Lin Li
Assistant Research Fellow, Experimental Forest, College of Bio-Resources and Agriculture