Thread by @PaulineProvini

Ever wondered what's happening inside a fish's mouth when feeding?
Check out our new paper, just published in @eLife, thanks to A. Brunet, A. Filippo and S. Van Wassenbergh @UMR_MECADEV @Le_Museum

elifesciences.org/articles/73621

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We can't see inside the buccal cavity without specific techniques, so we developed an #Xray based method to follow the water flows inside the fish's mouth.

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We also designed water tracers, just for the experiment. They needed to be of around the same density as water but also visible on Xray. So we inserted foam on a nickel rod... BY HAND 😮

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The fish swallowed the food, surrounded by water tracers, in front of a biplanar Xray system @UAFunMorph lab

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The 3D reconstruction revealed that water tracers and food tracers followed a different path

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During the intake, the water tracers spread in the entire buccal cavity, whereas food tracers followed a straight trajectory, suggesting an inertia-driven sorting mechanism

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In carp, the pattern looks like a “diverging flow”

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But in tilapia, the pattern suggested a ”central jet”...

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...which was confirmed by our CFD model

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What happened if the food got trapped in the branchial basket?
Periodical bidirectional water flows occurred:
The food was resuspended and carried more centrally towards the esophagus, thanks to the inertia-driven filter and flow patterns described in the intake.

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This new technique unveils a diversity of food transport mechanisms among species, fostering further research to explore water flow patterns, crucial for suction feeding.

Check out the whole story here: elifesciences.org/articles/73621

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