Endemic Insects in Pongso No Tao (Lan Yu)
Troides Magellanus and Xylotrupes gideon
Magellan birdwing butterfly (Troides magellanus(C. & R. Felder)) is one of the largest butterflies in Taiwan, the Kingdom of Butterflies. Wingspan of a female Magellan birdwing butterfly is as long as 15 center meters and as wide as 10 center meters. This species is found only in Lanyu (Orchid Island) of Taiwan. Its fore wings are black while the hind wings are golden. Hind wings of a male reveal red, green, and blue iridescence when viewed from certain angles. Magellan birdwing butterfly goes through complete metamorphosis. Its larva is colorful and feeds on Zollinger Dutchmanspipe. Its pupa is pupa adhaerena which hangs from a branch. Magellan birdwing butterfly is most active from March to April and from September to October. Its major nectar plant is Odollam Erberus tree. Comparing with other butterfly species, it flies relatively slow with a speed of four to five kilometers an hour. Due to depopulation of Zollinger Dutchmanspipe caused by farm land reclamation and over-collecting for its beautiful wings, the number of Magellan birdwing butterfly is in steep decline.  
Above Picture: Troides Magellanus
Xylotrupes Gideon is a type of rhinoceros beetle and an endemic species in Taiwan. It is mainly distributed in Lanyu, Green Island, and some regions in Taitung, Taiwan. A male has a cranial horn while a female has none. The major difference between Xylotrupes Gideon and ordinary rhinoceros beetles is its cranial horn and pronotom. The cranial horn of Xylotrupes Gideon is shorter and its pronotom has bifurcate prominence. It has one generation a year. An adult starts eclosion after spring and summer and is active from April to July. An adult feeds on resin of Fraxinus griffithi Hay. It performs a positive phototaxis response, so many Xylotrupes Gideon adults can be seen around street lamps during summer nights. It goes through complete metamorphosis. An egg of Xylotrupes Gideon is a white spheroid with a diameter of about 0.3 center meter. Eggs are laid in rotten wood or soil. Xylotrupes Gideon larvae, which are also called grubs, are white with brown heads. Grubs feed on rotten soil. The grub stage lasts for about 78 days, then grubs will molt, which is called “pupation”. 18 days later, Xylotrupes Gideon will shed pupal cases and reveal the still soft body before climbing up to the surface of ground. After body fluid spreads to its hinder wings, Xylotrupes Gideon will start its activity.
Above Picture: Xylotrupes Gide