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How do oysters use cilia and mucus to collect tiny food particles?

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Two wild horses graze on tall grass in the open prairie of Theodore Roosevelt National Park, with rolling badlands visible in the background. — Feeding behaviour Wild horses graze in the Badlands of North Dakota.

Oysters, like other bivalves, utilize their gills as specialized filtering devices to collect food. As the oyster holds its valves slightly open, tiny hairlike structures called cilia on the gill filaments perform wavelike motions that draw water into the mantle cavity.12

These cilia serve two primary functions: they create a constant flow of water through the gill and act as a filtration barrier that traps minute organic particles, such as plant detritus, bacteria, and algae. Once captured, the food particles are bound in mucus and transported by the cilia along the gill face into food grooves located at the dorsal axes or ventral margins of the ctenidia. From these grooves, the food-laden mucus is moved toward the labial palps, where further selection occurs before the material is finally ingested into the mouth.12