Search

Phenotypic variation in plants induced by biotic stressors can have cascading effects throughout arthropod communities. Habitat modifiers increase habitat complexity, which may promote species diversity and change arthropod species composition. A taxonomic approach to describe arthropod communities together with a trait-based approach might reveal mechanisms behind taxonomic changes and consequences for ecological processes. We previously found that the mistletoe Tristerix aphyllus induces susceptibility in the cactus Echinopsis chiloensis to the stem-borer beetle Xyletomerus sp., a habitat-modifier that drills brood chambers on cactus. Further, the community of arthropods that colonized chambers on parasitized cacti was more diverse and was different in composition compared to that found in chambers of non-parasitized cacti. We do not know whether the effects of brood chambers extend to the whole mistletoe-cactus system and how the arthropod community responds to seasonal phenology of mistletoe. Here we experimentally reduced the number of brood chambers and examined the effects on taxonomic and functional richness and composition, considering mistletoe seasonal phenology. We found a positive relationship between the number of chambers and arthropod species richness, abundance and functional richness. Arthropod taxonomic and functional richness were generally higher at mistletoe flowering compared to fruiting or mistletoe senescence/cactus flowering stages. Species composition varied with chamber number and changed with mistletoe seasonal phenology. Functional composition changed with mistletoe phenology. Functional richness and species richness were positively correlated, yet, functional redundancy is likely to occur. We conclude that cascading effects initiated by mistletoe extends beyond the chamber scale, up to the plant scale. [ABSTRACT FROM AUTHOR]

The mechanisms behind the unique capacity of the vine Boquila trifoliolata to mimic the leaves of several tree species remain unknown. A hypothesis in the original leaf mimicry report considered that microbial vectors from trees could carry genes or epigenetic factors that would alter the expression of leaf traits in Boquila. Here we evaluated whether leaf endophytic bacterial communities are associated with the mimicry pattern. Using 16S rRNA gene sequencing, we compared the endophytic bacterial communities in three groups of leaves collected in a temperate rainforest: (1) leaves from the model tree Rhaphithamnus spinosus (RS), (2) Boquila leaves mimicking the tree leaves (BR), and (3) Boquila leaves from the same individual vine but not mimicking the tree leaves (BT). We hypothesized that bacterial communities would be more similar in the BR–RS comparison than in the BT–RS comparison. We found significant differences in the endophytic bacterial communities among the three groups, verifying the hypothesis. Whereas non-mimetic Boquila leaves and tree leaves (BT–RS) showed clearly different bacterial communities, mimetic Boquila leaves and tree leaves (BR–RS) showed an overlap concerning their bacterial communities. The role of bacteria in this unique case of leaf mimicry should be studied further. [ABSTRACT FROM AUTHOR]