Although Darwin recognised long ago the destructive impact that snails and slugs have on seedlings, we understand remarkably little about why these herbivores select different plants at their most vulnerable stage. Hanley et al. examine the role of volatile compounds in the attractiveness of seedlings of 14 grassland species to snails (Cornu aspersum, Helicidae).
Selection is closely associated with different volatile profiles; specifically snails used characteristic odour cues (smell) to select preferred seedlings. The study shows how seedling selection occurs before snail attack, and explains why some plants avoid herbivory and establish even when molluscs are active and abundant.
Hanley, M. E., Shannon, R. W. R., Lemoine, D. G., Sandey, B., Newland, P. L., & Poppy, G. M. (2018). Riding on the wind: volatile compounds dictate selection of grassland seedlings by snails. Annals of Botany, 122(6), 1075–1083. https://doi.org/10.1093/aob/mcy190