Factors
affecting the swimming speed in the rotifer Brachionus plicatilis
M. Yúfera, E. Pascual-2003
Abstract :
Swimming
in rotifers is an activity demanding a high energy. Therefore it can be
affected by those intrinsic and extrinsic factors having a relevant
influence on the body metabolic activity. This study examines the swimming
speed in amictic females of Brachionus plicatilis in laboratory cultures.
Five different stages have been examined: recent hatched females, juveniles,
adult non-ovigerous females, ovigerous females with 1 attached egg and
ovigerous females with 2 attached eggs. Each animal was included in one of
these stages by examining the lorica size. Two temperatures, 15 and 25°C,
and two feeding conditions, presence and absence of microalgal cells, have
been tested. Twe swimming rates were measured by using an automated motion
analysis system over video recording. Swimming speed (µm/s) increased with
increasing body size while in the adult females it showed a decreasing trend
with the number of attached eggs. Regarding the culture medium conditions,
the swimming activity was higher at 25 than at 15°C and in absence than in
presence of microalgal cells. The average values under the different
experimental conditions ranged between about 500 for the recent hatched
females and 1300 µm/s for the adult non-ovigerous females. The present
results are discussed in relation to the metabolic rates described under
similar conditions.
(Instituto
de Ciencias Marinas de Andalucia (CSIC), Apartado Oficial, 11510 Puerto
Real, Cádiz, Spain, e-mail: manuel.yufera@icman.csic.es)