Impact of mating systems on life history traits in the invasive land snail Rumina decollata (Linnaeus, 1758)

Climate change and global transport are driving species introductions worldwide, with economic and ecological consequences. Hermaphroditic organisms can reproduce with any conspecific, and some can self-fertilize, increasing their colonization potential at low densities. This study examines how mating systems influence life history traits in the invasive land snail Rumina decollata by comparing individuals subjected to facultative cross-fertilization or enforced self-fertilization over two laboratory generations. Key life history traits—including size and age at first reproduction, fecundity, hatching period, and juvenile survival—were measured, along with individual growth and shell morphometry. Self-fertilizing individuals exhibited higher body weight at first reproduction but lower fecundity and delayed reproduction compared to cross-fertilizers. Selfed offspring (F2) showed delayed hatching and reduced survival, reflecting significant inbreeding depression compared to F2 outcrossed snails. While F1 self-fertilizing snails displayed faster growth than outcrossed counterparts, this advantage diminished in F2 selfed snails, whose growth declined—supporting cumulative effects of inbreeding depression. Shell shape remained similar between mating treatments. Despite fitness costs, 32% of self-fertilizing individuals produced at least one juvenile surviving beyond 15 days, demonstrating their potential to establish populations. This study improves our understanding of how the reproductive strategies of R. decollata shape life history variation under environmental constraints.