Ref ID : 1815
C. Charoy; Modification of the swimming behaviour of Brachionus calyciflorus (Pallas) according to food environment and individual nutritive state. Hydrobiologia 313/314:197-204, 1995
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The swimming behaviour of orthoclonal Brachionus calyciflorus (Pallas) females was studied with the aid of a system of automated trajectometry. The swimming was observed in response to the food environment and the individual's nutritive state. Eighteen hours before testing, neonates were placed either in a suspension of Chlorella, or in a freshwater medium. For each nutritive state, the test consisted of an analysis of the swimming behaviour of B. calyciflorus in 5 different environmental food conditions: in an algal suspension, in an algal solution (obtained from filtration of the algal suspension), in a freshwater medium, in the same freshwater medium with a suspension of polystyrene beads, and in the algal solution with the same suspension of beads. Three variables were used to describe the swimming path: linear speed (mm sec-1), angular speed (degrees sec-1), and mean angle (degrees). The results showed a modification in the swimming pattern dependent on both food environment and nutritive state of females. The nature of stimulations inducing these behavioural modifications, and their interactions with the individual nutritive state briefly discussed.