Locomotory Responses of the Cave Cyprinid Phreatichthys Andruzzii Chemical Signals from Conspecifics and Related Species: New Findings

Previous research on chemical communication among hypogean fishes have suggested that these species are attracted, as are epigean species, by the odour of non-injured conspecifics. Considerations on the biological meaning of such responses and some doubts about the reliability of the experimental procedure previously utilised, have led us to reconsider the matter and verify the results already obtained in the cave cyprinid Phreatichthys andruzzii. Using a new methodological approach we ascertained not only the absence of positive chemotaxis to odour of known or unknown conspecifics, but also the presence of a strong negative chemotaxis towards the odour of unfamiliar conspecifics and of individuals belonging to the closely related species Barbus conchonius. The biological meaning and the adaptive value of these reactions are briefly discussed.