These are the tiny wasp parasites emerging from the amazing golden chrysalis of a crow butterfly.
The best way to spot these golden sculptures is out at night, where their highly reflective surface shines bright in the torchlight. I have seen them on railings on the Peak and on Lung Fu Shan, and in more forested areas, under leaves, on a forest path. Always a wonder to behold, and very tricky to photograph, as it shines in the flash.
EXCERPT FROM THE BOOK THE BUGS OF HONG KONG...
This has to be one of the most beautiful chrysalises that I have ever seen—a shining gold pupa. A butterfly is just one of the creatures that might end up emerging from a pupa. Yes, pupa (and eggs, and caterpillars) frequently host parasitoids, which are insects that attack and destroy their hosts, sometimes eating them alive. Typically, like here, these are wasps, laying their own eggs inside a butterfly egg, caterpillar or pupa. I understand that this is actually quite a frequent occurrence, and clearly a huge disappointment for those who like to rear butterflies. This brings us to our word for today—“polyembryony". Some wasps just lay one egg, but that egg can divide into many identical embryos, which is called polyembryony. So, like here, a whole mass of wasps can emerge from a host. I must have counted at least 40 of these little guys climbing out and then rapidly flying away. I was lucky to get three in this shot, as this was the only one that did not fly away immediately after it emerged, and then two more were popping out. Trying to get a suitable depth of field on such a small subject while balancing flash diffusion on this highly reflective surface, trying to keep things sharp and not to leave the wasps in shadows meant that this was probably the most technically difficult shot I have ever taken.