Comparison of seedling and adult palatability in annual and perennial plants

Abstract

1. The relative palatabilities of the seedlings and adults of a range of British herbaceous plant species (14 annuals and 15 perennials) were compared using a generalist native herbivore (the slug Deroceras reticulatum) in a food-choice experiment. A palatability index (0 to 1) was devised. 2. A general linear model analysis showed that, overall, there was a highly significant difference between seedling and adult palatability. 3. In the majority of cases, seedlings were more palatable than adults. However, in species with highly palatable adults the opposite tended to be the case. 4. No consistent difference between annual and perennial species was seen with respect to the relative palatabilies of adults vs seedlings. 5. No evidence of a trade-off between seedling palatability and relative growth rate was found. 6. In view of the role that selective seedling predation may play in determining species composition in the field, the results of this experiment indicate the need for caution in making ecological inferences from the exclusive use of adult material in palatability tests.