DENSITY AND DISTRIBUTION OF EXTERNAL TASTE-BUDS IN CYPRINIDS

The aim of the present qualitative and quantitative study was to survey the density and distribution of external taste buds (TB) in 10 common European cyprinid species. TB pores were stained with silver nitrate and counted in 7 sample areas on the body and 3 on the fins. TB densities decrease from rostral to caudal and from ventral to dorsal. Highest densities were encountered in the gular region of the minnow (297 per mm2), white bream (291) and vimba (285), or at the forehead, in white bream (147). Of the fins, the pectoral showed highest densities (150 per mm2 in vimba, 138 in the minnow). The overall TB density rank from high to low is: minnow Phoxinus phoxinus, white bream Blicca bjoerkna, crucian carp Carassius carassius, vimba Vimba vimba, bream Abramis brama, roach Rutilus rutilus, bleak Alburnus alburnus, sun bleak Leucaspius delineatus, sabre carp Pelecus cultratus and bitterling Rhodeus sericeus. This is also a fair rank of life styles from benthivory to open water planktivory and surface feeding. A significant positive correlation exists between densities of external taste buds and the relative sizes of the brain stem facial lobes. An apparent compensatory relationship between vision and taste, but not lateral line, is discussed.