This photo comes courtesy of Michael Bok, the writer of Arthropoda and a graduate student doing research on Lizard Island in Australia.
Image by Michael Bok Flickr
He said the ant spent over an hour drinking from the pen…enough to turn its abdomen black. Michael tells us the pen is a Pilot Precise V7, and that he has seen two or three other ants doing the same thing since the first occurrence.
Apparently, the ink does them no harm.