麻豆淫院

It's a scene fit for a nature documentary: In the frigid ocean surrounding Antarctica, the water boils over as seabirds dive from above and marine animals like seals and whales rise from the depths to all feast on krill.

But zoom out and this flurry of activity is just a tiny speck in a desolate seascape. Scientists have been puzzled by how these various species are all able to find the same food source at the same time.

"It's hard to get across just how forbidding this environment is," said S枚nke Johnsen, a professor of biology at Duke University Trinity School of Arts & Sciences.

In research in the journal Proceedings of the National Academy of Sciences, Johnsen, Duke postdoctoral scholar Jesse Granger, and University of California, Davis colleague Gabrielle Nevitt tease out how multiple species of Antarctic seabirds forage together鈥攚ith takeaways for conservation and for crowd behavior.

Nevitt is a sensory ecologist who has studied how sensory cues trigger feeding aggregations in the Southern Ocean, focusing on petrel and albatross (procellariform) species. She describes how, when searching for food, some of these seabirds fly closer to the water and track a scented chemical called dimethyl sulfide (DMS) that is associated with krill. Other seabird species fly higher up and seem to watch the smellers, following their lead.

"Exploiting food is probably very competitive, but finding it is cooperative," said Nevitt.

Tracking the movement of these different bird species is incredibly challenging in the field. At a course in Sweden, Nevitt met Granger, a modeler, who offered to help and bring in her mentor, Johnsen, an animal vision specialist. The idea was to use computer modeling to better understand how these species interact when they are foraging.

"You treat each animal sort of like it's a video game character," said Granger. "You give it rules about how it should behave and then you get this emergent behavior."

Granger set up multiple scenarios of flocks, with different ratios of bird species that use smell and those that use sight to forage. She also adjusted how species responded to each other鈥攕ometimes just following what their neighbors do; other times, monitoring birds with complementary senses and following their lead.

Running these different scenarios, the team found that, indeed, the foraging strategies where different types of seabirds picked up cues from each other led to the most successful rates of finding food. Having even a few scent-tracking birds benefits those hunting visually to find prey, showing the importance of maintaining balanced populations in the wild to keep them resilient.

"The whole group does better when it's a mixture of different species using different strategies to forage," said Granger. "If you reduce past a certain tipping point in size or in proportion, then the whole group ends up collapsing."

Beyond informing conservation strategies, this kind of research could help us understand the dynamics of complex systems that feature many individuals鈥攅ven crowds of humans.

"When we go to the state fair, nobody knows where the entrance is," said Johnsen. Somehow, we all work together to funnel into the entrance. A small percentage of people that picks up certain cues may have an outsized impact on directing the movement of the crowd as a whole.