With the help of CRISPR, researchers were able to develop mutated ants without the ability to sense the pheromones they use to communicate. The resulting deficiencies in their mode of communication show just how important the capability for social behavior is to ants' survival in a colony.
Genetically Altered Ants
Ants build some of the most complex colonies in the animal kingdom. Despite the complexity of their colonies' structures, they are still able to thrive because of their incredible coordination and cooperation. Researchers from The Rockefeller University conducted an experiment that sheds light on the importance of social behavior in the survival and structure of a colony.
Using clonal raider ants, researchers genetically altered the specimen by disrupting a gene called odorant receptor coreceptor (orco), a gene that is responsible for their capability to sense the pheromones that they use to communicate. When they removed the said gene, the ants displayed severe deficiencies in their ability to survive in the colony.
Specifically, the mutant ants showed a deficiency in social behavior and fitness.
Unable To Fall In Line
To understand the role of pheromones further, another team of researchers from NYU School of Medicine, Arizona State University, Vanderbilt University, and the Perelman School of Medicine also disrupted orco and used Indian jumping ants in addition to clonal raider ants.
While the genetic manipulation was easy, the challenge then turned to keeping the mutants alive and integrating them into the colony. Once the integration was completed, researchers were able to note changes in social behavior almost immediately. Instead of traveling in a single file, which is what ants do by detecting the pheromones of the ant in front of them, the mutant ants were unable to fall in line.
Brain Shape Altered
More surprising for the researchers was the discovery that the mutant ants' brains had actually changed in shape in both species. Compared with experiments with other insects such as fruit flies whose brain shapes were not altered along with the mutation, the ants' brains seemed to have developed differently without the gene.
This suggests that ants, more than other insects, actually need the odorant receptors in order to develop properly and correctly. Somehow, they are more important to ants than to others.
Essentially, the researchers found that the mutant ants had become comfortable with being separated from the colony, and displayed strange behavior such as marching toward smells that they normally detest. In fact, one particular mutant ant even stole one egg, cleaned it with her antennae, and just suddenly sent warning pheromones that alarmed the non-mutant ants.
Because of the teams' findings, they believe that ants truly are exemplary models that will help us understand the role of genes and social behavior in a colony of creatures with the same genes but remarkably different behaviors.
The two separate but related studies, along with a third one, have been published in the journal Cell.