Scientists have made a surprising discovery regarding wild nematodes, commonly known as roundworms. These resilient creatures are known to form fleshy, writhing towers by climbing atop one another, a behavior previously only observed under laboratory conditions.
Published in Current Biology, the study conducted by researchers in Germany captured video evidence of several nematode species engaging in this unique behavior within their natural habitat. Notably, this finding illuminates how the worms utilize these living structures to elevate themselves onto animals or objects that can transport them to new environments, though many questions about this behavior remain unanswered.
Senior study author Serena Ding, associated with the Max Planck Institute of Animal Behavior, mentioned that while the existence of such worm towers was not a secret among scientists who study these organisms, it had attained a sort of mythical status in scientific literature. The absence of documentation on this behavior occurring in the wild led to questions on whether the towers were solely a product of laboratory conditions.
Ding expressed her curiosity about the phenomenon: “It’s just something that always bugged me. I mean, yes, we’re studying nematode collective behavior… but is it real?” Driven by this inquiry, she dedicated her research efforts to discover high-density populations of nematodes demonstrating tower-building behaviors in their natural environments.
After extensive months of research, Ding’s team, particularly co-author Ryan Greenway, succeeded in finding and recording instances of wild worm tower construction among decaying fruits in the orchards surrounding the University of Konstanz, one of three Max Planck Institute locations. The researchers not only documented these remarkable towers but also brought some specimens into a lab setting for further analysis. Additionally, the lab experiments involved manipulating the commonly studied Caenorhabditis elegans, a species frequently used in research, to observe the creation of these towers directly.
The research yielded a dual revelation: not only did the towers exist in nature, but they also confirmed a long-held theory that these structures serve as a mechanism for dispersing individuals. Ding stated, “This has always been thought of as a dispersal behavior, but nobody’s really confirmed it.”
The team observed that the tower-forming worms cling to passing animals, such as fruit flies, and use these interconnected structures as bridges, enabling them to traverse gaps that would otherwise be unreachable. Furthermore, the towers exhibited collective responsiveness to external stimuli, showing that they react to touch, suggesting a level of organization and communication among the worms.
Despite encountering these towers in their natural habitat, Ding and her colleagues discovered some unexpected aspects during their investigation. For instance, they found no evidence of distinct roles among the lab worms within the towers; instead, they displayed equal mobility, with no specific individual showing an advantage in occupying the pinnacle of the tower—the position that most benefits from the behavior.
The studied worms are genetically identical clonal organisms, raising questions about whether similar dynamics would occur among genetically diverse populations in the wild. Ding expressed her ongoing curiosity about this aspect: “Not everybody gets to disperse. So who gets to disperse? Are they helping each other? Are they cheating?”
The research team acknowledges that significant questions persist regarding the nature and purpose behind these worm towers. Lab-based experiments revealed that C. elegans could construct towers at multiple life stages, including adulthood. This challenges previous assumptions that only the dauer larval stage of the nematodes engaged in tower-building behavior. Interestingly, most of the towers identified in the wild consisted solely of dauer worms, suggesting that there might be specific conditions prompting this behavior during certain life stages.
This study marks just the beginning of a deeper exploration into the behavior of nematodes, as Ding and her team plan to investigate these enigmas further. Ding aims for her findings to emphasize the importance of studying organisms like C. elegans from a natural perspective rather than solely within laboratory frameworks. By understanding not only how such behaviors are generated, but also their ecological and evolutionary relevance, she believes that more nuanced insights can be achieved.
Ding noted, “For me, this is an important study where as a worm person, I can publish a study without using a single mutant and we’re just looking at the behavior and what those behaviors say.” Her anticipatory enthusiasm for continued research reflects a growing interest in understanding the complexities of these fascinating little creatures.
So, while the discovery of wild nematodes building towers may seem like a curious or even creepy piece of trivia, it opens up a wide avenue for scientific exploration and enriches the ever-expanding knowledge of animal behaviors.
The revelation that these microscopic worms engage in such remarkable social structures could change the way researchers think about nematodes and their behaviors, both in labs and in nature. As scientists continue to study this phenomenon, the mysterious world of wild nematodes may unravel further intriguing secrets that await discovery.
image source from：https://gizmodo.com/wild-worms-build-flesh-towers-and-are-closer-than-you-think-2000611200
