Mechanoreception and multimodal sensory integration in crustaceans: Insights into statocysts, antennular systems, and neural pathways

Abstract The sensory systems of crustaceans are remarkably adapted, allowing for effective mechanoreception, chemoreception, and multimodal integration in response to environmental inputs. This study’s main focus, mechanoreception, is mediated by specialized organs such as chordotonal organs, statocysts, and superficial hair cells. These systems react to motion instead of pressure and are extremely sensitive to low-frequency sounds (<2000 Hz). As a sound detector and balance mechanism, the statocyst is essential, because it triggers brain reactions to changes in density between its gelatinous mass and the surrounding water. Similar to this, antennular structures that combine hydrodynamic, tactile, and chemical cues — such as from aesthetascs and bimodal sensilla — provide essential sensory feedback. Muscle receptor organs (MROs) and specialized neurons enable the mechanosensory abilities of crustaceans, which include proprioception and motor control. Molecular studies demonstrate the intricacy of their brain networks by highlighting the role of Class A GPCRs (= G Protein-Coupled Receptors) and piezo-electric ion channels in sensory perception. Furthermore, nociceptive responses highlight the sophisticated neuronal adaptations of possible pain-detecting systems.