. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. FEATURED ARTICLES 181 videotape recorded through a dissecting microscope; on-screen magnification was lOOx. Water movement was generated with a motor that vibrated the diaphragms fitted to each end of the cylinder. The motor was powered with a sine wave generator and an amplifier. The resulting flagellar motion had a resonance frequency of 7-12 Hz that was evident at all imposed amplitudes of water motion (Fig. 1A). Furthermore, the flagellar motion consisted of two components: pivoting at the base, and an additional whippin
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. FEATURED ARTICLES 181 videotape recorded through a dissecting microscope; on-screen magnification was lOOx. Water movement was generated with a motor that vibrated the diaphragms fitted to each end of the cylinder. The motor was powered with a sine wave generator and an amplifier. The resulting flagellar motion had a resonance frequency of 7-12 Hz that was evident at all imposed amplitudes of water motion (Fig. 1A). Furthermore, the flagellar motion consisted of two components: pivoting at the base, and an additional whipping at the tip. The pivoting motion of the flagellum causes differences in relative water flow along its length. In particular, water displacement is greater than flagellar displacement at the basal region, whereas the reverse is true at the tip. Between these two extremes lies a "null" region where the water motion and flagellar displacement are equal (Fig. 1C), but phase differ- ences (not measured) could still cause relative water motion in the null region. This "null" region changes in location along the flagellum in response to changes in frequency. Additional whip action (resulting from the gradual decrease in diameter and stiffness toward the tip of the flagellum) causes complex, frequency-dependent changes in flagellar motion among the three locations (Fig. IB). Since the flagellum has different char- acteristic motions for different frequencies of water oscillation, it could provide the lobster with an analysis of frequency. From these biomechanical results, we conclude that the lateral flagellum could measure water motion with two different types of sensors: external flow detectors that would analyze relative water flow over the flagellar surface, and intersegmental stretch receptors that would measure flagellar bending. Uniform oscil- latory flow within the frequency range used in this study may not be a common occurrence in the lobster's natural en
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
