February 20, 2014
Ants Build Rafts To Protect Queen During Flood
When facing a flood, ants build rafts and use both the buoyancy of the brood and the recovery ability of workers to minimize injury or death, according to a study published in PLOS ONE on February 19, 2014 by Jessica Purcell from University of Lausanne, Switzerland, and colleagues. Furthermore, the queen ant is placed in the middle and protected on all sides by the rafting ants.
Researchers found that the worker ants and brood were extremely resistant to submersion. The workers protected the most vulnerable and valuable nest mate, the queen, by placing her in the center of the raft, and the worker ants used the buoyancy of the brood at the base and recovery ability of workers to create a raft and minimize ant injury or death. Both workers and brood exhibited high survival rates after they rafted, which suggests that occupying the base of the raft is not as deadly as scientists expected. Placing the brood at the base of the raft may also aid in keeping the nest together during the flood.
Dr. Purcell added, "We expected that individuals submerged on the base of the raft would face the highest cost, so we were astonished to see the ants systematically place the youngest colony members in that positions. Further experiments revealed that the brood are the most buoyant members of the society and that rafting does not decrease their survival; thus, this configuration benefits the group at minimal cost."