Fighting fish synchronize their moves--and their genes

[Judi Lynn]

By Elizabeth PennisiJun. 17, 2020 , 2:00 PM

When Muhammad Ali duked it out with Joe Frazier in the boxing ring, it’s unlikely anyone thought about what was happening to the genes inside their heads. But a new study in fighting fish has demonstrated that as the fish spar, genes in their brains begin to turn on and off in a coordinated way. It’s still unclear what those genes are doing or how they influence the skirmish, but similar changes may be happening in humans.

The work is “a really cool example of the way that social interactions can get under the skin,” says Alison Bell, a behavioral ecologist at the University of Illinois, Urbana-Champaign, who was not involved with the study.

The molecular basis of how animals, humans included, coordinate behaviors is a mystery. Whether it be mating or fighting, “animals need to be really good at this, but we don’t particularly know how they do it,” says Hans Hofmann, an evolutionary social neuroscientist at the University of Texas, Austin.

When molecular biologist Norihiro Okada at Kitasato University in Japan first saw Siamese fighting fish (Betta splendens) on TV, he realized the animals could help solve this mystery. Native to Thailand, these goldfish-size swimmers have been bred to have very large, vibrantly colored fins and tails. Aquarium owners tend to keep their pets, or “bettas” as they are often called, separate. The fish are territorial and can get into fights that last more than 1 hour, with strikes, bites, and chases (as seen in the video below). They will even lock jaws in a fish version of an arm wrestle.

Okada and colleagues videotaped more than a dozen hours of fights between 17 pairs of fish and then analyzed what happened—and when—in each fight. The longer the fight, the more the fish synchronize their behavior, timing their circling, striking, and biting more than anyone had ever realized, the researchers report today in PLOS Genetics.

More:
https://www.sciencemag.org/news/2020/06/fighting-fish-synchronize-their-moves-and-their-genes