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.

The consumption of seeds by animals can increase the germination probability because of seeds passage through animal guts. The loss of a native disperser by anthropogenic threats might be compensated by generalist alien seed dispersers. The aim of this work was evaluating the role of dogs (Canis lupus familiaris) and foxes (Pseudalopex spp.) for seed germination of the native fleshy-fruited tree Lithrea caustica. The effectiveness of dogs and foxes as seed dispersers of L. caustica was estimated through seed germination and post-germination viability of seeds obtained from faecal samples plus a control given by seeds collected directly from plant branches. Eleven replicates per treatment and 20 seeds per replicate were used. The experiment takes place 18 weeks with an ad libitum water supply (thermoperiod: 25.7 ± 0.1 °C/12.7 ± 0.2 °C, photoperiod: 12 h light/12 h darkness). Maximum germination occurred the week 18. The germination percentage of seeds consumed by dogs (24.5 %) did not differ significantly from the germination percentage of seeds consumed by foxes (28.2 %), although it was lower than that observed from the control (45.5 %). The post-germination viability of seeds did not differ significantly among types of seed consumers, although there was a tendency toward a lowered viability in seeds dispersed by dogs (40.5 %) rather than by foxes (80.7 %). Consequently, dogs eventually can surrogate the seed disperser role of foxes, although both mutualist animals seem to be inefficient seed dispersers of Lithrea caustica, because dogs and foxes decrease the germination capability of this fleshy-fruited native tree from central Chile.

El consumo de semillas por animales podría incrementar la probabilidad de germinación al pasar por el tracto digestivo animal. La pérdida de un dispersor nativo por causas de origen humano podría compensarse por dispersores generalistas introducidos. El objetivo de este trabajo fue evaluar el papel de los perros y zorros en la germinación y viabilidad de semillas de Lithrea caustica. Se comparó la eficacia de zorros y perros como dispersores de L. caustica mediante la germinación y viabilidad post-germinativa de semillas provenientes de heces, más un control dado por semillas colectadas directamente desde los árboles. Se consideraron 11 réplicas por tratamiento y 20 semillas por réplica. El experimento duró 18 semanas con un suministro de agua ad libitum (termoperiodo: 25,7 ± 0,1 °C y 12,7 ± 0,2 °C, y fotoperiodo: 12 h luz y 12 h oscuridad). La máxima germinación ocurrió el día 126. El porcentaje de germinación de semillas consumida por perros (24,5 %) no difirió significativamente del porcentaje de germinación de semillas consumidas por zorros (28,2 %), y ambos fueron significativamente menores que el control (45,5 %). La viabilidad de las semillas post germinación no difirió significativamente según el tipo de consumidor, aunque hubo una tendencia a que las semillas consumidas por perros fuesen menos viables (40,5 %) que las consumidas por zorros (80,7 %). Consecuentemente, los perros eventualmente pueden suplir el rol de los zorros pese a que ambos parecen ser mutualistas ineficientes de L. caustica al disminuir su capacidad germinativa, aunque no su viabilidad post germinación.