The next three days are dedicated to the only species arthropod that is actually 'protected" in Hong Kong ... including the plant, the larvae and the butterfly of the Birdwing Butterfly in Hong Kong.
These Caterpillars get really large...and I hasten to add that as these are a protected species I took these photos one morning "in situ" in a place that I know on Tai Mo Shan in mid October 2020.
The plant/vine they live on is equally interesting, especially as they strip it bare, revealing all the vines tendrils and its strange fruits. But more on that tomorrow.
The caterpillars are voracious eaters but move very little; a small group will defoliate an entire vine. If starved due to overcrowding, the caterpillars may resort to cannibalism. Fleshy spine-like tubercles line the caterpillars' backs, and their bodies are dark red to brown and velvety black. Some species have tubercles of contrasting colours, often red, or pale "saddle" markings. Like other members of their family, birdwing caterpillars possess a retractable organ behind their heads called an osmeterium. Shaped like the forked tongue of a snake, the osmeterium excretes a fetid terpene-based compound and is deployed when the caterpillar is provoked. The caterpillars are also unappealing to most predators due to their toxicity: the vines which the caterpillars feed upon contain aristolochic acid, a poisonous compound known to be carcinogenic in rats. The feeding caterpillars incorporate and concentrate the aristolochic acid into their tissues, where the poison will persist through metamorphosis and into adulthood.