Ambigolimax valentianus (also known as Lehmannia valentiana) is a species of terrestrial slug, a pulmonate gastropod mollusc in the family Limacidae.
It has spread very widely around the world, especially in greenhouses, where it can be a pest; in warmer climates it has often then spread outdoors. Comparatively much has been learnt about its life cycle and temperature relations. Dissection is necessary to reliably distinguish it from congeners in regions where these co-occur.
Ambigolimax valentianus eats green leaves and shoots, and consequently can be a pest in greenhouses or even outdoors. It also eats animal matter and fallen leaves. Activity and feeding start before sunset, peaking in the earlier part of the night. This species seldom climbs up trees and during the day is most commonly found under boards, rocks and plant containers. Often its first discovery in a country has been in greenhouses, from whence it has spread to gardens, other synanthropic habitats outdoors, and even to woodland, likely facilitated nowadays by global warming. Where it has been introduced, this species may become the dominant slug.
