A team of scientists, directed by Dr Anandasankar Ray from the University of California – Riverside, has found that ants communicate using hydrocarbon chemicals present on their cuticles.
This image shows a colony of Florida carpenter ants (Camponotus floridanus) with major and minor workers taking care of the brood. Image credit: Juergen Leibig.
According to their study, published this week in the journal Cell Reports, ants use powerful sense of smell to sense the chemicals present on the cuticle of individuals to precisely identify the different members of their society.
“Using this amazing high-definition ability to smell ant body odor, the ants can recognize the various castes in the colony as well as intruders from another colony,” Dr Ray said.
“This broad-spectrum ability to detect hydrocarbons is unusual and is probably a special property of social insects,” he added.
Dr Ray and co-authors employed a powerful electrophysiology method, to systematically test hydrocarbons present on the worker and queen cuticles that have previously been suspected to act as pheromone cues.
“We used electrophysiology to investigate the detection of cuticular hydrocarbons by female-specific olfactory sensilla basiconica on the antenna of Florida carpenter ants (Camponotus floridanus),” the researchers said.
The ants’ sensitivity to pheromones allows detection of very few molecules of hydrocarbons that stick close to the cuticle surface. This ability apparently allows individuals to recognize those ants that are very close to them within the crowded colony.
“This is a remarkable evolutionary solution for social networking in large colonies. A more volatile body odor cue would be confusing to associate with an individual and could overwhelm the olfactory system of the colony members by constantly activating it,” Dr Ray explained.
Ants, according to the study, may be capable of responding not just to the presence or absence of particular hydrocarbons but also to the particular way in which various hydrocarbons are blended.
In other words, pheromones might act as a kind of chemical barcode, which individuals in a colony use to recognize other members within the nest and their status as workers or queens.
“Perhaps ants are brainier than we’ve given them credit for,” the scientists concluded.
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Kavita R. Sharma et al. Cuticular Hydrocarbon Pheromones for Social Behavior and Their Coding in the Ant Antenna. Cell Reports, published online August 13, 2015; doi: 10.1016/j.celrep.2015.07.031
