Diel cycle inHoplosternum littorale(Teleostei): evidence for synchronization of locomotor, air breathing and feeding activity by circadian alternation of light and dark

Abstract

Die1 cycles of voluntary food intake, locomotor activity and air breathing were studied in Hoplosfernurn littorale (Hancock, 1828), a siluriform fish of the Callichtyidae family living in marshes in northern South America. The study was carried out with six groups of 30 fish each reared in 200-1 tanks equipped with demand-feeders and maintained under artificial light-dark conditions (13.5 L/10.5 D). Feed demand started at dusk and increased throughout the night with a peak between 02.00 and 05.00 hours, during which 3-h period the fish ate 40% of their total daily ration. There was a marked peak in air breathing and locomotion at dusk, followed by an increased feed intake. When the lightdark cycle was advanced by 9 h the observed phenomena were the same, so it is assumed that the lightdark alternation is the synchronizer. In starved fish, locomotor activity and air breathing were increased in the light phase.

Diel cycles inHoplosternum littorale (Teleostei): entrainment of feeding activity by low intensity colored light

“…1. Die1 changes in the pattern of feeding demand in Hoplosternum littorale during the experiment 1 (redrawn from Boujard et al 1990): a -before day D, the white lights are switched on between 5 h 45 min and 19 h 15 min, and a red light is switched on all the time (average from the 5 days preceeding day D); b -after day D, the lighting remains the same, but dawn and dusk are advanced by 9 h (average from the 5 days following day D). pushed a rod.…”

“…Entrainment of activity by red light has already been shown for one fish species, Sulmo truttu (Molina-Borja et al 1990). Much less is known about the entrainment of feeding by light in fish, but most authors report strong circadian patterns of feeding (Hoar 1942, Landless 1976, Eriksson & Van Veen 1980, Boujard et al 1990, 1991, Boujard & Leatherland 1992a.…”

Consommation volontaire d'aliments en situation d'alternance de lumière et d'obscurité chezHeterobranchus longifilis

“…Cette activité trophique nocturne a d'ailleurs été généralement observée chez divers siluriformes tels que Ictulurus punctatus (Hastings et al, 1972), Ictulurus melus (Eriksson et Van Veen, 1980), Silurus ghnis (Anthouard et al, 1987). et Hoplosternum littorule (Boujard et al, 1990). Une baisse d'intensité lumineuse est également susceptible de provoquer la prise de nourriture (Boujard et al, 1992).…”

“…Le silure africain Heterobranc1zu.r 1ongifili.s apparaît ainsi avoir un net comportement trophique nocturne tel que cela a été démontré chez les siluriformes, notamment ceux ayant fait l'objet d'études expérimentales, tels que Clarias gariepinu.~ (Hogendoorn, 198 1 ), Heteropneustes fissilis (Sundararaj et al, 1982), Hoplosternum littorale (Boujard et al, 1990(Boujard et al, , 1992. Ce comportement trophique nocturne n'est cependant pas strict car dans cette expérience 22 à 30 % de l'aliment sont consommés en phase d'éclairement.…”

The behavioral physiology of labroid fishes

“…A diel cycle in air breathing, locomotion, and feeding was found in the atipa Hop/osternum littorale (Boujard et al, 1990). When the light-dark cycle was shifted, so did these behaviors, indicating that the light cycle was the synchronizer.…”