|Mechanosensory properties of the mouthpart setae of the European shore crab Carcinus maenas|In: Marine Biology. Springer: Heidelberg; Berlin. ISSN 0025-3162, more
Carcinus maenas (Linnaeus, 1758) [WoRMS]; Marine
In decapod crustaceans, the largest density and diversity of sensilla, referred to as setae, is in general found on the mouthparts, but little is known about their sensory properties and thereby their functions. Here data are presented from mechanoreceptors from the two largest mouthparts, maxilliped 2 and 3, of the European shore crab Carcinus maenas. The mechanoreceptors were found to respond to either displacements of the entire seta or bending of the setal shaft. The displacement-sensitive cells encode both the amplitude and the velocity of the displacement and about half were found to be directional but most in a non-exclusive way. The amplitude of the stimulus is encoded in the number of spikes produced with a linear correlation. The velocity is encoded in the interspike intervals with shorter intervals at higher velocities. In the latter case, the correlation follows a power function. The physiological data is correlated with the morphology and usage of the maxillipeds were examined with scanning electron microscopy and macro video recordings respectively. Recordings were obtained from cells associated with four different setal types and they all showed similar mechanosensory properties supporting that the external morphology of setae is more closely connected to their non-sensory functions, e.g., mechanical manipulation of the food items. The details of the sensory properties together with the high setal density, especially on maxilliped 3, suggest that a large amount of tactile information is gathered during feeding.