Theba pisana usually lives in coastlands, in or near sandy habitats. In hot climates it aestivates often directly exposed to the sun, attached to grasses, shrubs or succulent plants, fence posts, tall weeds, and so on. It is common near beaches.
In dunes it can live on nearly bare sand poorly fixed by grasses. In the north the snails do not estivate but they climb on plants in dry weather. It does not survive serious winter frosts.
Theba pisana is often associated with Cochlicella acuta and Cernuella virgata, but it can live slightly deeper inside pure sandy habitats and is usually more common than Cochlicella acuta.
It is one of the most common snails in coastal regions from south Portugal to Greece. Snails were most abundant along roadsides and densities decreased dramatically with distance from roads in the South Africa.
Snails were observed on a wide variety of endemic and introduced plant species and appeared to have a catholic diet.
Theba pisana is also a significant pest of citrus, vines, legume crops and cereals in South Africa. In Australia, it feeds on a range of agricultural plants.
Theba pisana in Britain and France have an annual life cycle and breed in summer and autumn, while in the Mediterranean, they have a biennial life cycle with breeding in autumn and winter.
Theba pisana appear to have an annual lifecycle, breeding in autumn to winter and growing to adult size of about 14 mm diameter by the end of the following summer in the South Africa. Maturity is reached at half maximum shell size after 1 year.
Maximum shell size is attained after 2 years. This species of snail makes and uses love darts. The size of the egg is 2.2 mm. The population density can reach up to 300-700 snails m² in South Africa.
They are active mostly at night and especially during periods of high humidity, irrespective of temperature in the South Africa. Theba pisana is an intermediate host for the terrestrial trematode parasite Brachylaima cribbi.
Impact of invasions:
In addition to the direct negative effect of Theba pisana feeding on agricultural crops, it also has several other additional effects. It uses the stalks of cereals as aestivating sites, which in turn clogs machinery and fouls produce during mechanical harvesting.
According to Quick (1952) Theba pisana has been responsible for the extermination of native snail species as a result of competition for available food.
In their report on the status and potential impacts of alien invasive organisms in the fynbos biome, MacDonald & Jarman (1984) predicted that Theba pisana would have very little impact on ecosystem processes, such as nutrient cycling, energy flow and sediment dynamics or on the germination and succession processes of the plant community itself.
However, the snail could seriously impact directly on fynbos plants, by feeding on them, and also displace native herbivores by competing with them for resources, and these effects have not been studied.
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