How ants’ wonderful sense of smell controls their lives

To recognize such small differences requires an excellent precision in sense of smell, which ants seem to often use in order to determine their place within the colony, along with easily recognizing the nearby co-workers.

It’s a truly critical necessity for them to be able to accurately differentiate in between major groups within their swarming colony so they can achieve the excellent social experience they’re known to reach. They tested their sense of smell by measuring responses of individual neurons in the ants’ antennae.

The electrodes functions as sensors to know whether each antenna detects different hydrocarbons and if the ant recognized the odor. Most recently, ants have been shown to cooperate when transporting big chunks of food, they have been studied for how they manage to keep clean, and they have been examined also for why majority in a colony are lazy. Minute differences in each ant’s body odor provide behavioral cues that allow the insects to maintain complex social colonies with different roles for queens, workers, nurses and soldiers – all without saying a word.

Ultimately, depending on the cast it belongs to (queen, worker, warrior), each ant has its own blend made up of several cuticular hydrocarbons, the authors write in Cell Reports.

Ray’s team began by putting Florida carpenter ants (Camponotus floridanus) on glass slides under a microscope and zooming in 1,000 times on their antennae, so they could see the hundreds of tiny sensory hairs that coat them.

“To our surprise we found that these very low volatility compounds are not only detected sensitively by the ants” specialized antennal sensors, but nearly all of the hydrocarbon components are detected”, Anandasankar Ray, a neuroscientist and an associate professor of entomology at Riverside, said in a press release.

The hydrocarbons and pheromones might be acting as a sort of “chemical barcode”, the researchers say, allowing individual ants to identify and recognize other ants in the nest and their status as workers or queens – or perhaps invaders. As Ray explained, “the ants of the neighboring colony are able to recognize that immediately and they become extremely aggressive, sometimes killing an intruder very, very quickly”. The hypothesis suggested that ants aren’t sensitive enough to pick up hydrocarbons from nestmates with which they share too many pheromones.

Moreover, recognition of particular individuals at close proximity in a large crowd is facilitated by use of low volatility cuticular carbons, a substance exclusively found in ants.

“A more volatile body odour cue would be confusing to associate with an individual and could overwhelm the olfactory system of the colony members by constantly activating it”, he explained.

“This is a remarkable evolutionary solution for “social networking” in large colonies”, Ray said. When an ant went to a particular smell, the researchers rewarded it with sugar water.