Xylocopa nasalis

Common name(s): Bamboo carpenter bee

A large bee, reaching 26mm. Fully black. Wings with metallic blue, green and purple colours under sunlight. This species is not as sexually dimorphic (distinguishable) as many other species are, but the male can be recognized easily enough by the front of his head, including the clypeus and the spaces between the clypeus and eyes, being white or whitish-yellow.

This species is quite widely distributed across South China, and is probably the most common species in Hong Kong. It has often been misidentified as Xylocopa iridipennis or Xylocopa auripennis, both of which are not found in Hong Kong, and as Xylocopa tranquebarorum, another bamboo-nesting species which occurs in Hong Kong but is much smaller and usually found in rural areas. In 2014 and 2015, Dr John Ascher from the National University of Singapore (NUS) and myself closely examined numerous specimens of large bamboo carpenter bees collected across all of Hong Kong, and all proved to be this species. Therefore, although the possibility of other similar species being present in Hong Kong cannot be ruled out, it is highly unlikely.

This species is commonly seen feeding from flowers, and can be found in urban parks throughout spring and summer. Being a member of the subgenus Biluna, it is far more specialized in nesting habits than other species, and nests only in bamboo stems. These bamboo stems are used locally as scaffolding and to support small trees, as well as to make broom handles. Therefore, this species is common even in urban areas, and often causes unnecessary consternation due to its size and appearance.

The male of this species defends his territory from other males vigorously. This usually happens around 10 to 30 feet high, among the leaves of a tree. The males frequently get into rather aggressive fights, sometimes with both falling to the ground, although serious damage is seldom done.

Female at nest entrance on a bamboo stem

Male feeding on Ixora flowers in an urban park. Note the white parts on the front of the head, as well as brown hairs on the thorax and whitish hairs on the legs, all of which are absent in the female.