Impact of mating strategies on life-history traits in the alien land snail Rumina decollata

AO_SCPLOWBSTRACTC_SCPLOWClimate change and global transport are driving species introductions worldwide, leading to economic and ecological consequences. Hermaphroditic organisms are able to reproduce with any conspecific, and some can self-fertilize, enhancing their potential for population establishment despite low initial densities in colonization events. This study examines how mating strategies influence the life history traits of the alien land snail Rumina decollata by comparing individuals subjected to facultative cross-fertilization or enforced self-fertilization over two laboratory-reared generations. Key life history traits--including size and age at first reproduction, fecundity, hatching time, and juvenile survival--were measured, alongside individual growth and shell morphometry. Self-fertilizing individuals exhibited higher body weight at first clutch but lower fecundity and delayed reproduction compared to cross-fertilizers. Selfing offspring (F2) took longer to hatch and had lower survival rates, indicating significant inbreeding depression. Selfed snails of F1 grew faster than outcrossers, but experienced a decline in growth in F2, consistent with inbreeding depression. Conversely, shell shape remained similar between mating treatments. Although selfing imposed fitness costs, 32% of self-fertilizing individuals produced viable offspring, highlighting their ability to establish in new environments. This study improves our understanding of how R. decollatas reproductive strategies shape life history traits under environmental constraints. SIMPLE SUMMARYSpecies are spreading to new regions due to climate change and global transport, often causing environmental and economic challenges. Hermaphrodite species that can reproduce by cross or self-fertilization can establish populations even when few individuals are present. In our study, we examined how these two reproductive strategies affect a land snails growth, reproduction, and survival. We found that self-fertilizing snails grew larger and heavier but laid fewer eggs and reproduced later than those that mated with others. Additionally, their offspring took longer to hatch and had lower survival rates. These results suggest that self-fertilization comes with costs, likely due to inbreeding depression, but it still allows the species to establish in new environments. Despite lower survival, one-third of the self-fertilizing snails produced viable offspring, showing that this strategy can support population growth when mates are scarce. As this species continues to expand into new areas, our findings help explain how it adapts to different environments. Understanding these reproductive strategies is important for predicting its spread and managing its potential impact on ecosystems.