Phenotypic similarity between fruits of Gevuina avellana (Proteaceae) and wasp-induced galls of Nothofagus dombeyi (Nothofagaceae) does not protect fruits from predation by rodents

ABSTRACT

Fruits of Gevuina avellana (Proteaceae) seem to mimic wasp-induced galls of Nothofagus dombeyi (Nothofagaceae) to escape predation by rodents, which may change both spatially and temporarily. The objective of this study was to evaluate the similarity between the fruits of G. avellana and the galls of N. dombeyi and to determine if this similarity protects fruits from predation by rodents in a disturbed temperate forest. We evaluated: i) the similarity between fruits and galls by measuring length, diameter, weight and color; and ii) the effects of galls on fruit predation by offering them to rodents in varying proportions, in a forest and a meadow, over two years. Fruits and galls showed similar phenotypes but fruits were more consumed than galls, even at low fruit frequencies, suggesting that their similarities are not due to mimicry. Fruits escaped predation more in the meadow than in the forest, particularly during the second year, thus indicating spatio-temporal variability in the phenomenon. The similarity between fruits and galls seems to be the result of phylogenetic and/or developmental constraints, rather than the result of a Darwinian coevolutionary pathway mediated by rodents. However, mimicry may happen with other dry-fruited plants inhabiting deforested habitats, which encourages further studies.

Keywords:
Batesian mimicry; Aditrochus coihuensis; granivory; austral temperate forests; Chile