They measure just a millimeter long, but united are transformed into a superorganism. Nematodos are the most abundant animals on the planet and have one of the rarest capabilities of: they know how to climb on each other until their bodies form a living tower. If food begins to scarce or competition for it becomes fierce, these tiny worms are grouped into tens or even thousands of individuals to reach and conquer new spaces.
Until now, these aggregations were almost mythological. They had only observed in very controlled laboratory environments and not. But researchers in Constanza, Germany, have registered images of worms of the genre Caenorhabditis that rise on apples and pears falling in local orchards. The Max Planck Institute team of animal behavior and the University of Constance combined field work with laboratory experiments to provide the first direct evidence that the behavior of lifting in living towers occurs naturally and works as a means of collective transport for nematodes. The finding was published this Thursday in.
Serena Ding, a researcher at the Max Planck and main author of the study, explains that nicitation – the behavior in which the worm is put in vertical position, holds on her tail and moves her body in the air as if she were doing hasts of hutop – had already been studied by other research groups. However, its last inquiry addresses the collective aspect of dispersion, evidencing that worms are also grouped to adhere to fruit flies or other insects and thus “travel” on them. Ding had already noticed that it was going on spontaneously in his laboratory crops when he left plaques with nematodes without supervision. “These plaques often developed fungal contamination or other more complex structures than hungry worms used as scaffolding to climb,” he explains.
Then, a video came that changed everything. Ryan Greenway, co -author of the study, sent Ding a recording of a group of nematodes forming bridges between the rotten fruit of a garden near the university. “For a long time, natural worms towers existed alone in our imagination,” recalls the expert. “But with the right team and a lot of curiosity, we find them hidden in full view,” he adds.
That was not the only surprise. Traditionally, science had linked nicitation with a very specific stage in de los Nematodos: the Dauer stage. This is called a “alternative” larval stadium that worms adopt to survive in adverse conditions. “Our observations revealed that worms of all ages can form towers, which suggests that a different molecular mechanism could be involved that we believed,” says the author.
Mortal cooperation or trap
A nematode tower is not just a lot of worms. It is a coordinated structure that shows some directionality during its training, especially when they perceive the presence of potential mass means of transport. “For example,” says Ding, “when we touch the towers with a needle, worms tend to move more and crawl to that signal.” That is, to the touch. They also usually align within the tower, with the heads pointing towards the direction in which they want to move, which refers to an unusual degree of coordination for such a small animal.
When placing them in agar – a gelatinous substance that is used as a culture medium in microbiology – without food and with a toothbrush sow acting as a post, hungry worms began to self -assemble. In two hours, they emerged living towers that remained stable for more than 12 hours and were able to extend their exploratory arms towards the surroundings. Some even through certain holes to reach new surfaces.
“We suspect that in addition to touch, the detection of odors in the nematodes could play an important role,” Ding details. And he adds: “Chemical signals could help worms to locate resources or vectors, improving the effectiveness of collective dispersion.”
If compared to other collective transport systems in animals – like fish banks or bird flocks – worm towers are somewhat different. “There is a very strong physical overlap among individuals and very little long -distance coordination,” says the expert. In addition, despite the architectural of these structures, the worms inside did not show an obvious differentiation of roles, which hints an equal form of cooperation. “We are exploring whether there is a division of labor – which would suggest cooperation – or social traps – what would be a competition among individuals – in the formation of Torres, since only some individuals of the group manage to disperse successfully.”
The new study opens a new way to explore how and why they move together. In addition, having viscous and limb bodies, the formation of high structures in worms is quite remarkable. If scientists manage to understand how these non -adherent organisms build and maintain towers, they could inspire new ideas in mechanics and material engineering. “Although it is still early, this could have applications in the design of soft robotics, bio -inspired materials, or in the understanding of collective mechanics in other biological or technological systems,” Ding adventure.
