Raul Bonal - Academia.edu (original) (raw)

Papers by Raul Bonal

1. The abscission of seeds infested by insects is common in many plants and has been proposed as ... more 1. The abscission of seeds infested by insects is common in many plants and has been proposed as a defensive mechanism, although its negative consequences for insects have rarely been assessed.

Poster presentado al I Congreso Iberico de la Dehesa y el Montado, celebrado en Badajoz del 6 al ... more Poster presentado al I Congreso Iberico de la Dehesa y el Montado, celebrado en Badajoz del 6 al 7 de noviembre de 2013.

1. The timing of reproduction is predicted to match the period of maximum food availability. In t... more 1. The timing of reproduction is predicted to match the period of maximum food availability. In this sense, the case of many phytophagous insects in temperate regions is very illustrative, as their larvae usually depend on a resource only available for a limited period of time each year.

Plants can reduce the fitness costs of granivory by satiating seed predators. The most common sat... more Plants can reduce the fitness costs of granivory by satiating seed predators. The most common satiation mechanism is the production of large crops, which ensures that a proportion of the seeds survive predation. Nevertheless, satiation of small granivores at the seed level may also exist. Larger seeds would satiate more efficiently, enhancing the probability of seed survival after having been attacked. However, a larger seed size could compromise the efficiency of satiation by means of large crops if there were a negative relationship between seed size and the number of seeds produced by an individual plant. We analyze both types of satiation in the interaction between the holm oak Quercus ilex and the chestnut weevil Curculio elephas. Both crop size and acorn size differed strongly in a sample of 32 trees. Larger crop sizes satiated weevils, and higher proportions of the seeds were not attacked as crop size increased. Larger seeds also satiated weevil larvae, as a larger acorn size...

Microorganisms

Actinomycetes constitute a large group of Gram-positive bacteria present in different habitats. O... more Actinomycetes constitute a large group of Gram-positive bacteria present in different habitats. One of these habitats involves the association of these bacteria with insects. In this work, we have studied twenty-four actinomycetes strains isolated from the intestinal tract and feces from larvae of the xylophagous coleopteran Cerambyx welensii and have shown that seventeen strains present hydrolytic activity of some of the following substrates: cellulose, hemicellulose, starch and proteins. Fourteen of the isolates produce antimicrobial molecules against the Gram-positive bacteria Micrococcus luteus. Analysis of seven strains led us to identify the production of a wide number of compounds including streptanoate, alpiniamide A, alteramides A and B, coproporphyrin III, deferoxamine, demethylenenocardamine, dihydropicromycin, nocardamine, picromycin, surugamides A, B, C, D and E, tirandamycins A and B, and valinomycin. A significant number of other compounds, whose molecular formulae ar...

Ecology Letters

Synchronised and quasi-periodic production of seeds by plant populations, known as masting, is im... more Synchronised and quasi-periodic production of seeds by plant populations, known as masting, is implicated in many ecological processes, but how it arises remains poorly understood. Flowering and pollination dynamics are hypothesised to provide the mechanistic link for the observed relationship between weather and population-level seed production. We report the first experimental test of the phenological synchrony hypotheses as a driver of pollen limitation in mast seeding oaks (Quercus ilex). Higher flowering synchrony yielded greater pollination efficiency, which resulted in 2-fold greater seed set in highly synchronised oaks compared to asynchronous individuals. Pollen addition removed the negative effect of asynchronous flowering on seed set. Because phenological synchrony operates through environmental variation, this result suggests that oak masting is synchronised by exogenous rather than endogenous factors. It also points to a mechanism by which changes in flowering phenology can affect plant reproduction of mast-seeding plants, with subsequent implications for community dynamics.

Annals of Forest Science

& Key message Insect herbivory in novel Quercus ilex L. forests is a highly context-and scale-dep... more & Key message Insect herbivory in novel Quercus ilex L. forests is a highly context-and scale-dependent process. We show that forest composition, tree height and fine-scale spatial location, as well as tree genetic relatedness and ontogeny, can all influence herbivore activity at local to landscape scale. & Context Understanding the intrinsic and extrinsic drivers of herbivory in novel expanding forests is essential to envisage their role for biodiversity conservation. & Aims To analyse the effects of landscape attributes, forest composition, genetic relatedness, ontogeny and leaf traits on insect herbivory in novel Q. ilex forest stands. & Methods In 15 forest patches, we examined effects of patch size and connectivity, forest composition, tree height, specific leaf area (SLA) and nitrogen content on herbivory. In 3 forest patches, we assessed effects of tree genetic relatedness, ontogeny and spatial distribution. & Results Herbivory was lower in pine-oak than in mixed-oak forests owing to the shorter tree height in the former with no effects of patch size or connectivity. Herbivory increased with SLA whereas nitrogen content had no effect. Within patches, herbivory differed among genetic clusters and was reduced in saplings growing near mature oaks and individuals near the forest edge. & Conclusion We illustrate the strong context and scale dependence of tree-herbivore interactions that renders predictions for dynamic systems such as novel oak forests extremely challenging. It implies, however, that the structural heterogeneity of such unmanaged forests allows their function as stepping stones for insect herbivore diversity in fragmented landscapes.

Diversity

Iberian man-made oak savannahs (so called dehesas) are traditional silvopastoral systems with a h... more Iberian man-made oak savannahs (so called dehesas) are traditional silvopastoral systems with a high natural value. Scattered trees provide shelter and additional food to livestock (cattle in our study sites), which also makes possible for animals depending on trees in a grass-dominated landscape to be present. We compared dehesas with nearby treeless grasslands to assess the effects of oaks on ant communities. Formica subrufa, a species associated with decayed wood, was by far the most abundant species, especially in savannahs. Taxa specialized in warm habitats were the most common both in dehesas and grasslands, as expected in areas with a Mediterranean climate. Within dehesas, the number of species was higher below oak canopies than outside tree cover. Compared to treeless grasslands, the presence of oaks resulted in a higher species richness of aphid-herding and predator ants, probably because trees offer shelter and resources to predators. The presence of oaks changed also the ...

Araneus bonali sp. n., a novel lichen-patterned species found on oak trunks...

Authorea

DNA barcoding identification needs a good characterization of intra-specific genetic divergence t... more DNA barcoding identification needs a good characterization of intra-specific genetic divergence to establish the limits between species. Yet, the number of barcodes per species is many times low and geographically restricted. A poor coverage of the species distribution range may hamper identification, especially when undersampled areas host genetically distinct lineages. If so, the genetic distance between some query sequences and reference barcodes may exceed the maximum intra-specific threshold for unequivocal species assignation. Taking a group of Quercus herbivores (moths) in Europe as model system, we found that the number of DNA barcodes from southern Europe is proportionally very low in the Barcoding of Life Data Systems (BOLD). This geographical bias complicates the identification of southern query sequences, due to their high intra-specific genetic distance with respect to barcodes from higher latitudes. Pairwise intra-specific genetic divergence increased along with spatial distance, but was higher when at least one of the sampling sites was in southern Europe. Accordingly, GMYC (General Mixed Yule Coalescent) single threshold model retrieved clusters constituted exclusively by Iberian haplotypes, some of which could correspond to cryptic species. The number of putative species retrieved was more reliable than that of multiple threshold GMYC but very similar to results from ABGD and jMOTU. Our results support GMYC as a key resource for species delimitation within poorly inventoried biogeographic regions in Europe, where historical factors (e.g. glaciations) have promoted genetic diversity and singularity. Future European DNA barcoding initiatives should be preferentially performed along latitudinal gradients, with special focus on southern peninsulas.

Microorganisms

Ecology Letters

Annals of Forest Science

Diversity

Araneus bonali sp. n., a novel lichen-patterned species found on oak trunks...

Authorea