As an expert on things entomological, Calilasseia, can you tell me what this is? It's about the size of my little finger nail and was walking at a fair pace along a long wooden railing (hence the not very sharp photo). It got to the end, realized it couldn't go any further, turned round and started to go back. Any large ants it encountered gave way to it, but tiny ants didn't. In fact one seemed to nick a bit of the white stuff, which I assume the insect is carrying as some sort of protection.