Formosan Giant Stag Beetle
Dorcus formosanus Miwa,1929
The individual body size varies greatly. The male can range between 2.4-7.8 cm and the female between 3.3-4.7 cm. The anterior head has large mandibles with a protrusion at the base. Such robust large mandibles are the main feature of this species. The anterior thorax is dented like an arc and the elytra have vertical lines. The foreleg tibias have saw-like protrusions and the hindlegs are thornless.
The adults generally appear between April and August, feeding on tree juices. Nocturnally, they are strongly photokinetic, often gathering under the street lights. The larvae feed on the dead wood of Fagaceae plants, which are commonly called grub worms. It is an endemic species of Taiwan, extensively distributed over the broadleaf forests and mixed conifer-broadleaf forests in the mountains of 200-2000 meters. It has been discovered and recorded over Wulai, Lalashan, North Cross-Island Highway, Jianshan and Guanwu in the northern region; Anmashan, Songgang, Wushe, Aowanda and Sun Moon Lake in the central region; Liugui, Tengchi, Kenting and South Cross-Island Highway in the southern region.
Due to its larger size than other stag beetles, it has been very popular in the pet market. Despite being a protected animal, it is often illegally traded. This species is critically endangered because of its small number and overhunting.