Alex Wild is a photographer and biologist based in Urbana, Illinois. The Myrmecos blog tracks Alex's exploration of insects and the other little creatures that run the planet.
Formica obscuripes
Trophallaxis- the social sharing of regurgitated liquids- is a fundamental behavior in the biology of most ant colonies. One ant approaches another, asks for a droplet of food, and if her partner is willing the two spend anywhere from a few seconds to several minutes in what is best described as a myrmecological french kiss. The behavior is so central to the life of ants that the insects have an entire stomach, separate from their digestive gut, devoted as a reservoir for social sharing.
Although the act involves a transfer of food, it would be a mistake to think of the behavior as primarily a nutrient-dispersal mechanism. Ants do it far more frequently than nutrition requires. Trophallaxis also transfers chemical signals among nestmates, regulating a singular colony odor and sharing information about the needs of the colony. Think of it as the colonies' own internet.
Over the weekend I set out to rectify my rather embarrassing lack of decent trophallaxis photographs. We have a laboratory colony of Formica obscuripes that are ideal subjects, as these large ants are not only charismatic but engage in trophallaxis with what seems to be a nearly pathological frequency. Here are a few of the better shots.
To capture this series, I borrowed a technique from Benoit Guenard. I set a tall tupperware container inside the open, fluon-lined plastic tub housing a large and active laboratory ant colony. A 6" square of white paper affixed to the top of the tupperware created a plain white platform. In essence, I made a raised stage that allowed for photographing the ants in side view while still retaining them in their escape-proof nest.
Once the ants accept the structure they behave relatively normally on it, as if the platform were a natural extension of their territory. A drop of honey water entices them to feed, followed minutes later by a predictable cascade of trophallaxis.
Comments
Fantastic photographs. When you say these ants are large, what size do you mean?
Posted by: Adrian Thysse | October 19, 2009 12:41 PM
Amazing photos.
Posted by: Morgan Lythe | October 19, 2009 1:24 PM
The largest workers are about 8mm long. Not huge by insect standards, but pretty big as far as ants go.
Posted by: myrmecos | October 19, 2009 1:26 PM
Are you using flash or a constant light source?
Posted by: pilgebump | October 19, 2009 8:03 PM
These are with the MT-24EX twin flash, diffused. The first two images were done with the two flash heads in their regular position. For the bottom two I hand-held one head behind the ants and turned down the power on the other.
Posted by: myrmecos | October 19, 2009 8:57 PM
Wow! And not just because the photos are spectacular--because they are...breathtaking in fact--but because this behavior is compelling in its intimacy and functionality.
Posted by: jason | October 19, 2009 8:59 PM
So cool
Posted by: Andrew N | October 21, 2009 8:10 AM
These two ants appear to have different faces or at least head shapes from one another. Is it possible to tell individual ants apart by appearance or is this just a visual illusion?
Posted by: Kaas Baichtal | July 4, 2010 6:43 PM