Heij, M. de (1999) Phenotypic plasticity of the burying depth of Macoma balthica. Master's Thesis / Essay, Biology.
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Abstract
The bivalve Macoma bait hica has to deal with a trade-off between predation risk and food availability in order to determine its burying depth. To know more about the phenotypic plasticity of the burying depth of Macoma, experiments are done in the field with regard to predator presence of the Shore crab Carcinus maenas and the shorebirds the Knot Calidris canutus and the Oystercatcher Haematopus ostraiegus. By means of transplantation experiments it is determined whether the origin and the environment of the clam are important factors influencing the burying depth. The origin of a clam has an effect; the clams originating from near the gully bury significantly deeper at the same location than the clams originating from high on the tidal flat. The environment of the clam seems to have no effect upon the burying depth of Macoma, only little variation in burying depth between the treatments occurred during the second experiment. This might be due to the fact that the clams were already buried deep; possibly safer from predation. To know the effect of the environment of the clam upon the burying depth, it is recommended to repeat this experiment. A crab predator seems to have an effect upon the burying depth of Macoma. In the presence of a predator the clams seem to bury deeper, but this effect is not significant. The same results come out of the experiment with the shorebirds, now only the effect of predator presence is tested. Another outcome of both experiments seem to be that the condition of a clam has a positive effect upon the burying depth of Macoma. With increasing condition the burying depth is increasing. Another experiment is done to look at the effect of clam density upon the burying depth of Macoma. Macoma living in a low density bury significantly deeper than those living under medium- or high-density categories do. Besides these experiments an observation on the burying depth of Macoma at different locations on the tidal flat during the season is done. The burying depth of Macoma is dependent on the time of the year, but also on the initial depth. Macoma that are buried deep do not react much on change in time, while the shallow living ones bury deeper. Thus differences in burying depth between Macama of different locations change in time. As predator presence seems to have an effect on the burying depth of Macoma, it is recommended to repeat this experiment and to test again the effect of 'environment' besides predator presence. The origin of a clam is of importance; it would be interesting to look whether the difference in burying depth can be inherited by their offspring.
| Item Type: | Thesis (Master's Thesis / Essay) |
|---|---|
| Degree programme: | Biology |
| Thesis type: | Master's Thesis / Essay |
| Language: | English |
| Date Deposited: | 15 Feb 2018 07:44 |
| Last Modified: | 15 Feb 2018 07:44 |
| URI: | https://fse.studenttheses.ub.rug.nl/id/eprint/9415 |
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