On January 12, the International Space Station crew unloaded the recently-arrived Antares rocket, which contained precious cargo like food, spare parts and tiny satellites. Along for the ride was a colony of ants with a very unique purpose: to demonstrate how the ever-efficient insects adapt to life in microgravity.
If you’ve ever had an ant invasion in your home, you know this pattern: A single ant finds a source of nourishment and then turns into a milling mass of ants ferrying food back to the colony. Meanwhile, individual ants fan out to investigate the rest of the room.
These behaviors do not come from the queen or some other central force. Instead, they are built on innate algorithms that ants developed over millions of years, according to Stanford University. Ants have poor vision, so they rely on smell and touch for guidance while exploring. When the number of ants is more dense, they are more likely to touch each other, which triggers them to explore in tight spirals. If they run into a low number of other ants, they walk in a straight line. This combination means that they spend more time thoroughly exploring an area that is interesting enough to attract other ants and cover a lot of ground while exploring other regions.
It’s a system that interests robotics researchers. If a fleet of robots is exploring a collapsed building, they can work more quickly if they don’t have to rely on a central commander to tell them where to go.
But what happens if you disrupt the very basis of the ants’ communication system? Stanford University researchers decided to answer the question by sending ants into space, where low gravity would alter how many times they encounter other ants. About 70 ants were placed in a container that shifted in size to reveal different behaviors.
“In microgravity, the struggle to walk interferes with interactions, in particular the relation between density and interaction rate,” said biology professor Deborah Gordon, who designed the experiment. “Thus each ant has less information about density, and so less information to influence its path shape and searching behavior.”
How the ants react could inform robot behavior in scenarios where radio communications have been interrupted. If it’s smoky or dusty and they can no longer communicate, the robots could develop a new system on the spot that still allows them to search an area thoroughly and efficiently.
Gordon, whose interest in ants began with a broader interest in central control-free systems like brains and embryos, said it is “very exciting” to send an experiment to the ISS. Her team will now study video from the ants’ time aboard the space station to work out how they responded to microgravity.