Friday, Jul 24, 2026 The claims desk. Receipts included. POWERED BY LENZ ↗
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SCIENCE

The Claim

In lophotrochozoan invertebrates, including annelids and mollusks, chemosensory ionotropic receptors detect environmental chemical signals and mediate sensory perception, especially aquatic olfaction and gustation.

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The Short Version

Current evidence supports a chemosensory role for ionotropic receptors in annelids and mollusks, but not as conclusively as the claim suggests. Peer-reviewed studies show conserved IR genes and expression in olfactory or gustatory organs of lophotrochozoans such as Aplysia, Capitella, and Sepia. The main limitation is that direct receptor-level and behavioral proof in these taxa is still limited compared with arthropods.

Caveats

  • Most lophotrochozoan evidence is based on gene homology and expression in sensory organs, not direct ligand-binding or electrophysiological demonstration of receptor function.
  • The claim can be misread as showing that ionotropic receptors are the proven main or universal chemosensory pathway in annelids and mollusks; that has not been established.
  • Protostome-wide conservation and strong arthropod data support the inference, but they do not automatically prove identical function in every annelid or mollusk lineage.

The Receipts

  1. Chemosensory ionotropic receptors in human host-seeking...

    PubMed Central (NIH)

  2. Ionotropic and metabotropic mechanisms in chemoreception

    PubMed Central (NIH)

  3. Ancient Protostome Origin of Chemosensory Ionotropic Glutamate Receptors

    PLOS Genetics

  4. Putative chemosensory receptors are differentially expressed in the sensory organs of the crown-of-thorns starfish, Acanthaster planci

    PMC

  5. Sensory sea slugs: Towards decoding the molecular toolkit underlying olfactory perception in molluscs

    PMC

  6. Variant Ionotropic Receptors Are Expressed in Olfactory Sensory Neurons of Coeloconic Sensilla on the Antenna of the Desert Locust, Schistocerca gregaria

    PMC (Journal of Comparative Neurology)

  7. Whole-head recording of chemosensory activity in the marine annelid Platynereis

    PMC (eLife)

  8. A putative origin of the insect chemosensory receptor superfamily in the nippostrongyle nematode

    eLife

  9. The Structure and Function of Ionotropic Receptors in Drosophila

    Frontiers in Molecular Neuroscience

  10. Functional properties of insect olfactory receptors: ionotropic...

    PubMed Central (NIH)

+ 11 more sources — see the full list on Lenz

Filed Under

AnnelidaIonotropic ReceptorsLophotrochozoaMollusca