A study on the chemosensory organs, feeding behavior, and attractant substances of Babylonia areolata

Because of the complex aquatic environment, it is difficult to research the behavior of shellfish. As we all know, although the ivory shells have high commercial value in China, the feeding behavior and attractant substances of the ivory shell ( Babylonia areolata ) has rarely been reported so far. Understanding its feeding behavior and attractants are helpful for supporting the development of aquaculture. In this study, we found that the surface of the tentacles and rhinophore were distributed with dense cilia and had a "9 + 2" motile cilia structure, and the osphradium were distributed with many sensory cells containing pigmented granules and nerve fibers in a linear fashion, as well as many nerve cells distributed on each olfactory leaf. Chemosensory organ resection experiments showed that there was no significant difference in the feeding response rate of B. areolata in the rhinophore resection group compared with the control group ( P > 0.05), but it was significantly reduced in the tentacles resection and co-resection groups ( P < 0.05). Six amino acids including leucine, phenylalanine, tyrosine, glutamic acid, glycine and taurine had strong attractant activity on B. areolata , and the mixtures of glutamic acid, leucine, phenylalanine, glycine, and taurine were better than the monomeric amino acid at all concentrations. B. areolata had a marked preference for the meat of Ruditapes philippinarum and Crassostrea angulata that could rapidly release highly attractive amino acids (glycine and glutamic acid). Further studies found that B. areolata had a distinct diurnal feeding rhythm under natural conditions, which would be broken and exhibited a strong feeding response both in the natural and satiated conditions when the food was consistently present. This study accumulates basic data for the study of feeding behavior and further contributes to the optimization of feeding strategies and the development of feed attractants in B. areolata . • The tentacles, rhinophore and osphradium were important chemosensory organs in the feeding process of B. areolata . • B. areolata have a marked food preference for bivalve shellfish . • Leu, Phe, Tau, Tyr, Glu and Gly had strong attractant activities on B. areolata. • B. areolate had a distinct diurnal feeding rhythm under natural conditions.