Bilan de 4 années d'étude du comportement reproducteur et de l'hybridation chez Barbus barbus (L., 1758) et Barbus meridionalis (RISSO, 1826)

Abstract

Cet article synthétise les résultats de 4 années d'étude du comportement de reproduction et de l'hybridation chez Barbus barbus (L., 1758) et Barbus meridionalis (Risso, 1826) en aquarium.On y aborde successivement la description des parades sexuelles, la mise en évidence du comportement d'hybridation, l'étude des rythmes biologiques nycthéméraux et l'influence des stimuli visuels sur les comportements sexuels. Mots-clés : comportement reproducteur, Barbus barbus, Barbusmeridionalis, hybridation, rythmes biologiques. FOUR YEARS RESEARCH ON THE REPRODUCTIVE BEHAVIOUR AND HYBRIDIZATION OF BARBUS BARBUS AND BARBUS MERIDIONALIS. ABSTRACTThis paper reviews the main results of 4 years studies on the reproductive behaviour of Barbus barbus (L., 1758) and Barbus meridionalis (Risso, 1826) under controlled conditions in aquarium. The reproductive behaviour is described as well as the behavioural mechanisms of hybridization. During the spawning act -sometimes preceded by «forehead swim» in which two fish swim together, at high speed, head against headthe female and the few accompanying males rise from the gravel and move their genital papilla in the gravel while releasing ova or sperm ( fig. 1 and 2). The reproductive behaviours of Barbus barbus and Barbus meridionalis appear to be similar and hybridizations were observed, showing that no complete behavioural barrier blocks the mating of the two species ( fig. 2). The daily rhythms of activity are compared within the two species. The influence of temperature and daylength on the daily rhythms of activity is discussed. In winter conditions, barbels exhibit a night activity rhythm. Spawning occurs during daytime or during the night (fig. 3). The influence of spawning stimuli is analysed using dummies of different sizes and colors (photo I). Barbels seem to prefer white, grey, yellow and brown colors to red or black colors.

Thermal related variations of seasonal and daily spawning periodicity in Barbus barbus

“…This then delays further spawning till preferred light intensities around sunset. This delay was not observed in aquaria held under constant medium light intensity (Poncin, 1994). At a seasonal level, B. barbus spawned very early in 1993 but this was consistent with the precise thermal threshold for spawning activities (daily minimum water temperature d13·5 C) observed in previous studies (Baras, 1993).…”

Riverine spawning and reproductive segregation in a lacustrine cyprinid species flock, facilitated by homing?

“…The lower risk of predation in shallow waters during the night (Dgebuadze et al, 1999) might also be involved. Except for its daily timing, the spawning behavior of L. brevicephalus closely resembled the European barb Barbus barbus (Baras, 1994;Poncin, 1994. Also for some labeobarb species (e.g., B. tsanensis) males appeared to migrate prior to females.…”