Group+6+Intro

Brown, S.W.P*, Cullen, F.S, Blackman, J., Charleson, C., Favarao, T.F, Baron, S.J, Mussard, J.D

__Introduction__

The grove snail (//Cepaea nemoralis//) is a land snail belonging to the family Helicidae with a shell ranging from 18 to 25mm in width. It is found in Western Europe commonly on dunes, in cultivated areas, and as high as 2100 meters in the Pyrenees, preferring the warmer microclimates. Being one of the most well-known snails because of the polymorphism it displays, which is caused by its genetic components, and consequently also has a range of bright colours including pink, yellow and brown as background colour with 0-5 dark brown bands. The visible polymorphism of Cepaea provides an excellent opportunity to study the interactions between ecology and genetics, and so has been highly studied and even noted from the time of Linnaeus. The polymorphism is extensive and easy to score, and Cepaea is common in a variety of habitats such as gardens and other urban areas. The grove snail has a close relative the white-lipped snail (//Cepaea hortensis//) which adopts the same habitat and also closely resembles the grove snail in terms of morphology. However, the grove snail tends to reach a greater size when mature. Another important distinction is the colour of the lip on each of the species shells. In the grove snail this lip is dark brown, whereas in the white-lipped snail it is usually white. It is important to note that a particular morph of the grove snail also has a white lip. As a consequence, dissection is generally required to correctly identify the species. There are other characteristics in each species that also differ, such as the structure of the love dart. The genetics of most of the C. nemoralis shell polymorphisms is directly related to its genome. Genes controlling the major polymorphisms for shell colour, presence or absence of bands, lip colour, and type of band pigmentation are borne together as a supergene. Other unlinked loci modify the number of bands on a banded shell. The degree of band fusion, minor variation in band number, and the degree of dominance of some alleles are polygenically controlled. __Experimental design__ The data was collected from Pulpit Hill, Monks Risborough. The weather was cloudy and there was heavy rainfall causing the ground to become muddy and waterlogged. Six different samples were taken. From the top of the hill two samples were taken from within the trees, two from the tree-grass borderline and two in the grass/bush area. The two samples were carried out to give repeats of the sampled type of habitat at 30m distance between each site. Being at the top of the hill means that the study examines the change in habitat rather than change in altitude when investigating varying shell colour and pattern. Each sample site was studied for one hour, recording shell colour, banding pattern, dead or alive and adult or juvenile.