This citrus long-horned beetle (Anoplophora chinensis) is a long-horned beetle native to Hong Kong, where it landed on our balcony, in SaiKung.
Here it is, just taking off back into the wild!
It is also known as the starry sky beetle, and in China, Japan, China and Korea, it is considered a serious pest.
Each beetle can lay up to 200 eggs after mating, and each egg is separately deposited in tree bark. After the beetle larvae hatches, it chews into the tree, forming a tunnel that is then used as a place for beetle pupation (the process of growing from larvae to adult, which takes 12-18 months). Infestations by the beetle can kill many different types of hardwood trees as well as citrus trees, and many others.
The Antennae have 11 segments in both sexes. The Antennae of females are approximately 1.2 times the length of the body; antennae of males are very long, approximately 1.7 to 2 times the body length, and have alternating white and black bands.
Why the long horns or Antennae? These are sometimes referred to as "feelers," and are paired appendages used for sensing in arthropods. Functions may variously include sensing touch, air motion, heat, vibration (sound), and especially smell or taste. Olfactory receptors on the antennae bind to free-floating molecules, such as water vapour, and odours including pheromones.
All pictures taken using a standard 100mm (macro) lens, with fill-in off body flash.