Ghost Ants

These are Tapinoma melanocephalum, aka Ghost ants, aka 'tramp ants'. They're pretty interesting:

'The ghost ant is thought to be so named because the legs and abdomen of the insect look transparent, with only the head and thorax being dark brown in colour.'

'When crushed, the workers emit an odor similar to that of rotten coconuts'

Ghosts ants are tiny, only 1.5mm in length (1/16 of an inch). They feed mainly on sweet things like honeydew melons which 'they collect from plant-feeding insects'.

These ants are drinking what is probably a mixture of food coloring added to sugared water.