These were photographed by Dr. Mohamed Babu after his wife noticed the white abdomens of the ants that sipped spilled milk in their kitchen.
Dr Babu set colored sugar water on paraffin in his garden (see the trees reflected in the droplets?). The paraffin allowed the drops to keep their shape as the ants partook.
Dr Babu found that the ants preferred yellow and green. I'd go for red, myself.
You can read more about Dr. Babu's efforts in the Daily Mail Online, or check out a sonnet about the ants (which tipped me off to this story) at Suppertime Sonnets.