Association of shell banding and habitat in a colony of the land snail theba pisana

Abstract

The Mediterranean snail Theba pisana is polymorphic for shell banding. In an introduced colony in Western Australia, the frequency of effectively unbanded shells is higher in exposed habitats than in adjacent thickets of Acacia bushes. This association holds for both unbanded shells and banded shells without upper bands. These results are most easily explained in terms of climatic selection. © 1980 The Genetical Society of Great Britain.