Though a blowfly that refuses to leave you alone might suggest otherwise, insects are generally useless when it comes to recognizing individual faces. One exception to the rule, however, is the Northern paper wasp, or Polistes fuscatus, which has the ability to tell one of its peer's faces from another. New analysis of the insect's genetics indicate these complex skills evolved incredibly quickly, a trend that sheds light on the evolution of intelligence and advantageous traits as a whole.
The study was carried out by genetics researchers at Cornell University looking to better understand not just which traits the Northern paper wasp had evolved, but how quickly they had taken them on and why.
“The big question we want to explore is how complex traits evolve. What is the mode and tempo of cognitive evolution?” said lead researcher Michael Sheehan. “The really surprising conclusion here is that the most intense selection pressures in the recent history of these wasps has not been dealing with climate, catching food or parasites, but getting better at dealing with each other. That’s pretty profound.”
Sheehan and his team studied the evolution of the Northern paper wasp by assembling its genome, along with that of its two closest relatives. This enabled them to tease out the genetic variations and reveal DNA signatures that indicated the rapid selection of certain mutations.
“We were looking for sections of DNA that lack diversity,” Sheehan said. “That suggests there are times when a new mutation appears that’s so beneficial, it sweeps the population. The longer the stretch of DNA lacking diversity, the more recent and intense selection would have to be.”
Through its analysis, the team found a strong and rapid selection by genes linked to insect vision, learning and memory, all crucial to facial recognition. They believe this took place in just the last few thousand years. Meanwhile, the two close relatives of the Northern paper wasp exhibited no strong patterns of genetic selection for learning or memory, suggesting that facial recognition was a big driver in the evolution of Polistes fuscatus.
The small handful of insects that do recognize faces all belong to communal societies with multiple queens, where the skill is believed to be crucial in telling one queen from another and establishing a hierarchy. While the research was carried out on wasps, the team sees the evolution of the insect as a model for understanding how intelligence evolves more broadly.
“Our findings indicated that cognitive evolution is not necessarily incremental,” Sheehan said. “There are mutations happening that can cause big shifts. This suggests the possibility that rapid adaptation of cognitive ability could have been important in other species as well, like language in humans.”
The research was published in the journal Proceedings of the National Academy of Sciences.
Source: Cornell University
