Slugs descending on mucus threads

At night and during rain slugs crawl up trees and bushes. In the morning, as the air humidity decreases, they do not retrace their track but just crawl downwards. If the branch is bent down, the slug will crawl to its end and then continue the downward movement on a thread of mucus. The mucus thread of Deroceras reticulatum (O. F. Müll.) gets up to 60 cm long with the slug descending at 10 cm per minute; that of Arion fasciatus (Nilsson) is up to 27 cm. Going down on mucus threads can be considered a behavioural feature of slugs as an ecological form. This method of descending has appeared in different families as a result of convergence

Dispersal of terrestrial gastropods by birds during the nesting period

We observed a blackcap Sylvia atricapilla L. (Sylviidae) which carried terrestrial gastropods Fruticicola fruticum (O. F. Müller) (Bradybaenidae) and Zonitoides nitidus (O. F. Müller) (Zonitidae) in a deciduous forest. Similarly, a blackbird Turdus merula L. (Turdidae) was observed carrying a slug, Arion subfuscus s. l. (Arionidae), in a dry pine forest. Z. nitidus was transported over a distance of at least 48 m, while A. subfuscus, no less than 25 m. The possibility of terrestrial gastropod dispersal by birds during the chick-feeding period is discussed