PARENTAL CARE IN TERRESTRIAL GASTROPODS

Parental care in terrestrial gastropods includes the preparation of ov iposition sites, production of large, heavily-yolked eggs supplied wit h calcium carbonate, provisioning of hatchlings with eggs in species w ith facultative sibling cannibalism, egg retention, and ovoviviparity. Evidence for true viviparity is scarce in terrestrial gastropods, as it is for postlaying care of eggs, though external egg carrying on the shell occurs in a few species. Care of young has not been-observed in any terrestrial gastropod species. Provisioning of eggs with nutrient s and calcium carbonate might be the most common form of parental inve stment. Ovoviviparity allows terrestrial gastropods to persist in habi tats otherwise unsuitable for oviparous species (e.g. exposed rock wal ls). An interspecific comparison demonstrates that egg-retaining and o voviviparous species produce smaller clutches than oviparous species a nd suggests a cost of parental care.