Topic B
Differences in the acceptability of foods between C. nemoralis and H. aspersa
Food is one of the factors influencing the distribution and abundance of a species (e.g. Chang 1991).
Reading about this topic provided the undergraduate with an insight into which plants had previously been tested. A preliminary survey of the snails' habitat indicated which plant species were abundant in the vicinity of the snails and could, therefore, realistically be considered as potential food plants. Based on this information 14 flowering plants were chosen as test species.
In this design the snails must be able to indicate their choice of food so an alternate plant is required. Preliminary reading and a pilot study indicated that lettuce could be used as an acceptable alternative. The undergraduate then carried out a final pilot study to determine the amount of food each snail species ate on average during a 12 hour period. This allowed the student to ensure adequate food was provided during the test.
References
CHANG, H.W. (1991). Food preference of the land snail Cepea nemoralis in a North American population. Malacological review24: 107 - 114.
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