Gerard van Buurt sent me some herpetological literature on the foraging of the Puerto Rican Ground Lizard, Ameiva exsul. Lewis (1989) studied the diet selection of this lizard and found that snails made up 17% of the total preys that were identified by diet analysis of this species. Both Subulina octona and Bulimulus guadalupensis (which are common species on Puerto Rico) equally counted for 7% of the preys. Compared to their occurrence in the habitat, snails were overrepresented in the identified preys.
This literature search was triggered by observations on Cura??ao, where Bulimulus guadalupensis is occurring in some gardens in Willemstad. The local lizard Cnemidophorus murinus has been seen catching this snail.
However, the Bulimulus seem to thrive only in gardens where lizards are infrequent. Dogs (especially large dogs) of the garden owners are probably the ‘hidden protectors’ of these snails, as they chase the lizards away and thus create possibilities for the snails to survive.
Lewis, A.R., 1989. Diet selection and depression of prey abundance by an intensively foraging lizard. – Journal of Herpetology 23: 164-170.