Portland State University. Department of Biology
Date of Publication
Master of Arts (M.A.) in Biology
1 online resource (38 p.)
The dispersal and dispersion patterns of Hydra fusca were examined. Hydra were placed in petri dishes at various densities. The water in the dishes was swirled forcing the animals to the center. The location of each animal was marked at time intervals thereafter. Analyses of the dispersal rates and dispersion patterns were made. Hydra dispersed from a central release point at a non-random rate. There was rapid movement from the center followed by a minimal daily movement. This eventually resulted in a uniform dispersion pattern at high densities in a limited environment. There was a relationship between the ratio of nearest neighbor distances to expected distances and the density. The inhibition of growth with an increase in density was demonstrated. The decrease of density through distribution of the polyps in a uniform pattern could be related to the release of a growth inhibiting substance into the medium.
Ruffing, Faith E., "The Dispersal and Dispersion Patterns of Hydra Fusca in a Limited Environment" (1977). Dissertations and Theses. Paper 2556.