Littoraria irrorata

Littoraria irrorata, common name the marsh periwinkle, is a species of sea snail, a marine gastropod mollusk in the family Littorinidae. The specific epithet irrorata means 'moistened' or 'dewy.' This species occurs in salt marshes on the Atlantic coast and Gulf Coast of North America, from Massachusetts to Texas. Some colonies of this species of snail are the only mollusks known to practice fungiculture. The maximum recorded shell length is 29.2 millimetres (1.15 in). This species can be found along Ireland, the Northwest Atlantic Ocean and the Gulf of Mexico. Littoraria irrorata feeds on fungi that it encourages to grow. It creates and maintains wounds on the grass, Spartina alterniflora, which are then infected by fungi, probably of the Phaeosphaeria and Mycosphaerella genera. Such fungi are the preferred diet of the snail. L. irrorata also deposits faeces on the wounds that they create, which encourage the growth of the fungi because they are rich in nitrogen and fungal hyphae. Juvenile snails raised on uninfected leaves do not grow and are more likely to die, indicating the importance of the fungi in the diet of L. irrorata. The minimum recorded depth for this species is 0 metres (0 ft); maximum recorded depth is 22 metres (72 ft).