Graduation Year

2010

Location

Center for Natural Science, Illinois Wesleyan University

Start Date

10-4-2010 2:35 PM

End Date

10-4-2010 3:35 PM

Description

Rotifers are free-swimming aquatic animals that feed by collecting particles through the use of cilia that are arranged around the mouth in two circular whorls. Specimens of Brachionus plicatilis exposed to 6µm and 0.5µm polystyrene beads (together or separately) captured the particles at significantly different rates. Calculation of the Jacob's Selectivity Index (D) revealed a significant selectivity for the larger (6µm) beads, over the smaller (0.5µm) beads (p <0.001), and the presence of 6µm beads negatively affected the capture of 0.5µm beads (p<0.001). We propose that the clearance rate (volume cleared of particles/time) of 0.5µm beads approximates fluid transport rates through the digestive system, and represents the mechanism of capture of bacteria-sized particles. Comparison of food intake through bacterial feeding to the metabolic rate of B. plicatilis revealed that bacteria are not likely a significant energy source. Bacterial concentration ≥ 108 cells/ml (100 x typical values) are necessary for feeding on bacterial to support at least 33% of the metabolic demand.

Included in

Biology Commons

Share

COinS
 
Apr 10th, 2:35 PM Apr 10th, 3:35 PM

Using Polystyrene Beads to Estimate Feeding Selectivity and Potential Energetic Consequences in the Rotifer, Brachionus plicatilis

Center for Natural Science, Illinois Wesleyan University

Rotifers are free-swimming aquatic animals that feed by collecting particles through the use of cilia that are arranged around the mouth in two circular whorls. Specimens of Brachionus plicatilis exposed to 6µm and 0.5µm polystyrene beads (together or separately) captured the particles at significantly different rates. Calculation of the Jacob's Selectivity Index (D) revealed a significant selectivity for the larger (6µm) beads, over the smaller (0.5µm) beads (p <0.001), and the presence of 6µm beads negatively affected the capture of 0.5µm beads (p<0.001). We propose that the clearance rate (volume cleared of particles/time) of 0.5µm beads approximates fluid transport rates through the digestive system, and represents the mechanism of capture of bacteria-sized particles. Comparison of food intake through bacterial feeding to the metabolic rate of B. plicatilis revealed that bacteria are not likely a significant energy source. Bacterial concentration ≥ 108 cells/ml (100 x typical values) are necessary for feeding on bacterial to support at least 33% of the metabolic demand.