Natures wonders: wood boring clams live in own poop (Introduction)

by David Turell , Saturday, December 17, 2022, 17:41 (495 days ago) @ David Turell

A very ecological family tree:

https://www.sciencedaily.com/releases/2022/12/221215191626.htm

"Deep beneath the waves, tiny clams with shells usually about as big as a pea bore into pieces of sunken wood. The wood is food for them, as well as a home. These rare, scattered, sunken pieces of wood support miniature ecosystems where different wood-boring clam species can live in harmony for years. But in a new paper in Marine Biodiversity, researchers found that one group of wood-boring clams has evolved a unique way to get the wood all for itself: building chimneys made of poop.

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"Deep beneath the waves, tiny clams with shells usually about as big as a pea bore into pieces of sunken wood. The wood is food for them, as well as a home. These rare, scattered, sunken pieces of wood support miniature ecosystems where different wood-boring clam species can live in harmony for years. But in a new paper in Marine Biodiversity, researchers found that one group of wood-boring clams has evolved a unique way to get the wood all for itself: building chimneys made of poop.

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"As the clams dig and move into their boreholes in the wood, they fill the space around them inside the holes with their own feces.

"'They don't do it on purpose, their anatomy makes them do it," says Voight. "When these clams bore into wood, their little shell does the boring." Meanwhile, the clams' siphons, tubular appendages for taking in water to get oxygen and expelling waste, stick out behind them. "In most wood-boring clams, these two "in and out" siphons are equal in length and stick out into the water column," says Voight. "But in these related hyper-nasty borers, the siphon for expelling de-oxygenated water and feces is short; it stays inside the borehole in the wood. As a result, says Voight, "they poop in their borehole. They just have to, unless they really, really push." The waste stays right there with the clam, forming a chimney that wraps around the siphon.

"That animals would evolve an anatomy that keeps them in such close contact with their own waste, is surprising, says Voight: "It sure isn't very hygienic, and yet they show no evidence of immune problems. They're healthy, they're clearly going to town on the wood. So why did they evolve this way?"

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"'This group of species of clam has been shown in previous studies to be unusually tolerant of low oxygen," says Voight. They also have additional adaptations, like a mucosal lining of their fecal chimneys, and a substance like hemoglobin in their blood that picks up more oxygen; both may reduce the risk of sulfide poisoning from the waste. Taken together, these adaptations allow these species to survive in conditions that would make non-related wood-boring clams sick. The end result is more wood for the chimney-producing species to eat, live in, and for their offspring to settle on, unbothered by competitors.

"Beyond just solving the mystery of the gross chewed-up wood with an even grosser solution, Voight says that the study illustrates the importance of looking at ecology with an understanding of how different species are related to each other.

"'When you're confronted with something that seems enigmatic, sometimes you need to step back and look at the big picture, put a lot of different studies together, to see how what had appeared to be enigmatic is a product of evolution," says Voight. "Having a good family tree can help reveal patterns, and the more we know about the evolutionary histories of these different groups, the more we'll be able to find out about how they fit together.'"

Comment: amazing study. And it develops from reasons to study the right picture. Look at ecology and ecosystems. Wood is good food source. Ask termites