Search

The swift advancement of digital and artificial intelligence (AI) technology has offered new avenues for improving library educational experiences. The study discussed in this article examines the efficacy of incorporating AI-powered academic animations and chatbots into library resources to increase user engagement, knowledge retention, and overall learning outcomes. The findings indicate that AI-driven educational animations offer interactive and visually compelling material. This results in substantial enhancement of users' perception of challenging concepts and boosts their curiosity to explore library resources. Additionally, incorporating chatbots as virtual assistants provides individualized support, responding in real-time to users--particular needs and inquiries, promoting a more effective and user-friendly library experience. The study emphasizes how AI-driven academic animations and chatbots can revolutionize library learning spaces, offering users a more engaging, appealing, approachable, and valuable learning environment. The study suggests further research into these technologies and their integration into library systems. They focused on multidisciplinary collaboration and creating standards of excellence to ensure cutting-edge tools, successful deployment, and long-term sustainability. [ABSTRACT FROM AUTHOR]

Three large saproxylic cerambycids with different pest/legal status co-occur in the Iberian oak woodlands, Cerambyx welensii (Cw), Cerambyx cerdo (Cc) and Prinobius myardi (Pm): Cw is an emerging pest, Cc is a protected but sometimes harmful species and Pm is a secondary/minor pest. A precise taxonomic diagnosis is necessary for research, management or protection purposes, but may be problematic mainly because Cw and Cc larvae are morphologically indistinguishable. To resolve this constraint, we genotyped adults, larvae and eggs collected over a wide geographical range using the mitochondrial barcoding of the cytochrome c oxidase subunit I (COI). A Neighbour-Joining tree phylogram revealed three distinct clusters corresponding to Cw, Cc and Pm. We further first sequenced for Cw and Cc two mitochondrial (12S rRNA and 16S rRNA) and one nuclear (28S rRNA) gene fragments. For the first two genes, interspecific divergence was lower than in COI , and for the 28S (lower mutation rate), the two species shared identical haplotypes. Two approaches for species delimitation (General Mixed Yule Coalescent (GMYC), Barcode Index Number (BIN)) confirmed the species distinctiveness of Cc and Cw. The Bayesian COI gene tree showed a remarkable genetic divergence between Cc populations from Iberia and the rest of Europe. Such divergence has relevant taxonomic connotations and stresses the importance of a wide geographical scale sampling for accurate DNA barcoding species identification. Incongruities between morphology/lineage and COI barcodes in some individuals revealed natural hybridization between Cw and Cc. Natural hybridization is important from a phylogenetic/evolutionary perspective in these cerambycids, but the prevalence of (and the behavioural/ecological factors involved in) interspecific cross-breeding remain to be investigated. [ABSTRACT FROM AUTHOR]

The structure and asymmetry of the longest tail feathers of 26 bird species, which was measured on the basis of rachis width, and the number and length of barbs is examined. The results of the study suggested that a trait's susceptibility to express developmental instability by fluctuating asymmetry depends on its structural composition.

The fundamental trade-off between current and future reproduction has long been considered to result in a tendency for species that can grow large to begin reproduction at a larger size. Due to the prolonged time required to reach maturity, estimates of tree maturation size remain very rare and we lack a global view on the generality and the shape of this trade-off. Using seed production from five continents, we estimate tree maturation sizes for 486 tree species spanning tropical to boreal climates. Results show that a species' maturation size increases with maximum size, but in a non-proportional way: the largest species begin reproduction at smaller sizes than would be expected if maturation were simply proportional to maximum size. Furthermore, the decrease in relative maturation size is steepest in cold climates. These findings on maturation size drivers are key to accurately represent forests' responses to disturbance and climate change., (© 2024 John Wiley & Sons Ltd.)

Increasing food production while avoiding negative impacts on biodiversity constitutes one of the main challenges of our time. Traditional silvopastoral systems like Iberian oak savannas ("dehesas") set an example, where free-range livestock has been reared for centuries while preserving a high natural value. Nevertheless, factors decreasing productivity need to be addressed, one being acorn losses provoked by pest insects. An increased and focalized grazing by livestock on infested acorns would kill the larvae inside and decrease pest numbers, but increased livestock densities could have undesired side effects on ground arthropod communities as a whole. We designed an experimental setup including areas under trees with livestock exclosures of different ages (short-term: 1-year exclusion, long-term: 10-year exclusion), along with controls (continuous grazing), using DNA metabarcoding (mitochondrial markers COI and 16S) to rapidly assess arthropod communities' composition. Livestock removal quickly increased grass cover and arthropod taxonomic richness and diversity, which was already higher in short-term (1-year exclosures) than beneath the canopies of control trees. Interestingly, arthropod diversity was not highest at long-term exclosures (≥10 years), although their community composition was the most distinct. Also, regardless of treatment, we found that functional diversity strongly correlated with the vegetation structure, being higher at trees beneath which there was higher grass cover and taller herbs. Overall, the taxonomic diversity peak at short term exclosures would support the intermediate disturbance hypothesis, which relates it with the higher microhabitat heterogeneity at moderately disturbed areas. Thus, we propose a rotatory livestock management in dehesas: plots with increased grazing should co-exist with temporal short-term exclosures. Ideally, a few long-term excluded areas should be also kept for the singularity of their arthropod communities. This strategy would make possible the combination of biological pest control and arthropod conservation in Iberian dehesas., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)

The benefits of masting (volatile, quasi-synchronous seed production at lagged intervals) include satiation of seed predators, but these benefits come with a cost to mutualist pollen and seed dispersers. If the evolution of masting represents a balance between these benefits and costs, we expect mast avoidance in species that are heavily reliant on mutualist dispersers. These effects play out in the context of variable climate and site fertility among species that vary widely in nutrient demand. Meta-analyses of published data have focused on variation at the population scale, thus omitting periodicity within trees and synchronicity between trees. From raw data on 12 million tree-years worldwide, we quantified three components of masting that have not previously been analysed together: (i) volatility, defined as the frequency-weighted year-to-year variation; (ii) periodicity, representing the lag between high-seed years; and (iii) synchronicity, indicating the tree-to-tree correlation. Results show that mast avoidance (low volatility and low synchronicity) by species dependent on mutualist dispersers explains more variation than any other effect. Nutrient-demanding species have low volatility, and species that are most common on nutrient-rich and warm/wet sites exhibit short periods. The prevalence of masting in cold/dry sites coincides with climatic conditions where dependence on vertebrate dispersers is less common than in the wet tropics. Mutualist dispersers neutralize the benefits of masting for predator satiation, further balancing the effects of climate, site fertility and nutrient demands., (© 2023. The Author(s), under exclusive licence to Springer Nature Limited.)

The tropical Andes are one of the most important biodiversity hotspots on Earth, yet our understanding of how their biotas have responded to Quaternary climatic oscillations is extraordinarily limited and the alternative models proposed to explain their demographic dynamics have been seldom formally evaluated. Here, we test the hypothesis that the interplay between the spatial configuration of geographical barriers to dispersal and elevational displacements driven by Quaternary cooling-warming cycles has shaped the demographic trajectories of montane oak forests (Quercus humboldtii) from the Colombian Andes. Specifically, we integrate genomic data and environmental niche modelling at fine temporal resolution to test competing spatially explicit demographic and coalescent models, including scenarios considering (i) isotropic gene flow through the landscape, (ii) the hypothetical impact of contemporary barriers to dispersal (i.e., inter-Andean valleys), and (iii) distributional shifts of montane oak forests from the Last Glacial Maximum to the present. Although our data revealed a marked genetic fragmentation of montane oak forests, statistical support for isolation-with-migration models indicates that geographically separated populations from the different Andean Cordilleras regularly exchange gene flow. Accordingly, spatiotemporally explicit demographic analyses supported a model of flickering connectivity, with scenarios considering isotropic gene flow or currently unsuitable habitats as persistent barriers to dispersal providing a comparatively worse fit to empirical genomic data. Overall, these results emphasize the role of landscape heterogeneity on shaping spatial patterns of genomic variation in montane oak forests, rejecting the hypothesis of genetic continuity and supporting a significant impact of Quaternary climatic oscillations on their demographic trajectories., (© 2023 The Authors. Molecular Ecology published by John Wiley & Sons Ltd.)

The relationships that control seed production in trees are fundamental to understanding the evolution of forest species and their capacity to recover from increasing losses to drought, fire, and harvest. A synthesis of fecundity data from 714 species worldwide allowed us to examine hypotheses that are central to quantifying reproduction, a foundation for assessing fitness in forest trees. Four major findings emerged. First, seed production is not constrained by a strict trade-off between seed size and numbers. Instead, seed numbers vary over ten orders of magnitude, with species that invest in large seeds producing more seeds than expected from the 1:1 trade-off. Second, gymnosperms have lower seed production than angiosperms, potentially due to their extra investments in protective woody cones. Third, nutrient-demanding species, indicated by high foliar phosphorus concentrations, have low seed production. Finally, sensitivity of individual species to soil fertility varies widely, limiting the response of community seed production to fertility gradients. In combination, these findings can inform models of forest response that need to incorporate reproductive potential., (© 2022. The Author(s).)

Despite its importance for forest regeneration, food webs, and human economies, changes in tree fecundity with tree size and age remain largely unknown. The allometric increase with tree diameter assumed in ecological models would substantially overestimate seed contributions from large trees if fecundity eventually declines with size. Current estimates are dominated by overrepresentation of small trees in regression models. We combined global fecundity data, including a substantial representation of large trees. We compared size-fecundity relationships against traditional allometric scaling with diameter and two models based on crown architecture. All allometric models fail to describe the declining rate of increase in fecundity with diameter found for 80% of 597 species in our analysis. The strong evidence of declining fecundity, beyond what can be explained by crown architectural change, is consistent with physiological decline. A downward revision of projected fecundity of large trees can improve the next generation of forest dynamic models., Competing Interests: Competing interest statement: C.J.C. and J.C. are coauthors on a 2020 article; S.J.W. and J.C. are coauthors on a 2019 article; J.R.P. and J.C. are coauthors on a 2020 article; M.U., J.K.Z., and J.C. are coauthors on two 2019 articles; and M. Silman, W.F.R., and J.C. are coauthors on 2018, 2019, and 2020 articles.

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 are not included in the Dictionary of Natural Products (DNP), were also present in the extracts analyzed, which opens up the possibility of identifying new active antibiotics. Molecular identification of ten of the isolated bacteria determined that six of them belong to the genus Streptomyces , two of them are included in the genus Amycolatopsis and two in the genus Nocardiopsis.

DNA barcoding identification needs a good characterization of intraspecific 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 intraspecific 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. This geographical bias complicates the identification of southern query sequences, due to their high intraspecific genetic distance with respect to barcodes from higher latitudes. Pairwise intraspecific 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., Competing Interests: The authors declare that there is no conflict of interests regarding the publication of this article., (© 2020 The Authors. Ecology and Evolution published by John Wiley & Sons Ltd.)

Background and Aims: The ability of plants to allocate energy to resistance against herbivores changes with abiotic conditions and thus may vary along geographical clines, with important consequences for plant communities. Seed size is a plant trait potentially influencing plant tolerance to endoparasites, and seed size often varies across latitude. Consequently, plant tolerance to endoparasites may change across geographical clines., Methods: The interaction between Quercus ilex (holm oak) and seed-predating Curculio spp. (weevils) was explored along most of the latitudinal range of Q. ilex. This included quantification of variation in seed size, survival likelihood of infested seeds, multi-infestation of acorns and community composition of Curculio weevils in acorns., Key Results: Larger seeds had a higher probability of surviving weevil attack (i.e. embryo not predated). Southern populations of oak produced on average four times larger seeds than those of northern populations. Consequently, the probability of survival of infested acorns decreased with latitude. The community composition of Curculio varied, with large weevils (C. elephas) dominating in southern populations and small weevils (C. glandium) dominating in northern populations. However, damage tolerance was robust against this turnover in predator functional traits. Furthermore, we did not detect any change in multi-infestation of acorns along the geographical gradient., Conclusions: Quercus ilex tolerance to seed predation by Curculio weevils increases toward the southern end of its distribution. Generally, studies on geographical variation in plant defence against enemies largely ignore seed attributes or they focus on seed physical barriers. Thus, this research suggests another dimension in which geographical trends in plant defences should be considered, i.e. geographical variation in tolerance to seed predators mediated by seed size., (© The Author(s) 2018. Published by Oxford University Press on behalf of the Annals of Botany Company. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

The predator satiation hypothesis posits that masting helps plants escape seed predation through starvation of predators in lean years, followed by satiation of predators in mast years. Importantly, successful satiation requires sufficiently delayed bottom-up effects of seed availability on seed consumers. However, some seed consumers may be capable of quick aggregative and reproductive responses to masting, which may jeopardize positive density dependence of seed survival. We used a 17-yr data set on seed production and insect (Curculio weevils) infestation of three North American oaks species (northern red Quercus rubra, white Q. alba, and chestnut oak Q. montana) to test predictions of the predation satiation hypothesis. Furthermore, we tested for the unlagged numerical response of Curculio to acorn production. We found that masting results in a bottom-up effect on the insect population; both through increased reproductive output and aggregation at seed-rich trees. Consequently, mast seeding in two out of three studied oaks (white and chestnut oak) did not help to escape insect seed predation, whereas, in the red oak, the escape depended on the synchronization of mast crops within the population. Bottom-up effects of masting on seed consumer populations are assumed to be delayed, and therefore to have negligible effects on seed survival in mast years. Our research suggests that insect populations may be able to mount rapid reproductive and aggregative responses when seed availability increases, possibly hindering satiation effects of masting. Many insect species are able to quickly benefit from pulsed resources, making mechanisms described here potentially relevant in many other systems., (© 2018 by the Ecological Society of America.)

The new species Araneusbonali Morano, sp. n. (Araneae, Araneidae) collected in central and western Spain is described and illustrated. Its novel status is confirmed after a thorough revision of the literature and museum material from the Mediterranean Basin. The taxonomy of Araneus is complicated, but both morphological and molecular data supported the genus membership of Araneusbonali Morano, sp. n. Additionally, the species uniqueness was confirmed by sequencing the barcode gene cytochrome oxidase I from the new species and comparing it with the barcodes available for species of Araneus . A molecular phylogeny, based on nuclear and mitochondrial genes, retrieved a clade with a moderate support that grouped Araneusdiadematus Clerck, 1757 with another eleven species, but neither included Araneusbonali sp. n. nor Araneusangulatus Clerck, 1757, although definitive conclusions about the relationships among Araneus species need more markers examined and a broader taxonomic coverage. The new species was collected on isolated holm oaks and forest patches within agricultural landscapes. Adults were mostly trapped on tree trunks, where their lichen-like colours favour mimicry, while juveniles were collected on tree branches. Specimens were never found either in ground traps or grass samples. This species overwinters as egg, juveniles appear in early spring, but reproduction does not take place until late summer-early autumn. Araneusbonali Morano, sp. n. was found in the same locality from where another new spider species was described. Nature management policies should thus preserve isolated trees as key refuges for forest arthropods in agricultural landscapes, as they may be hosting more unnoticed new species. After including Araneusbonali Morano, sp. n. and removing doubtful records and synonymies, the list of Araneus species in the Iberian Peninsula numbers eight.

Insect herbivory decreases plant fitness by constraining plant growth, survival and reproductive output. Most studies on the effects of herbivory in trees rely on correlational inter-individual comparisons and could, thus, be affected by confounding factors linked to both herbivory and plant performance. Using the Mediterranean Holm oak (Quercus ilex) as a study model, we followed an experimental approach in which leaf-feeding insects (mainly Lepidoptera caterpillars) were excluded from some shoots in all study trees. Shoots subjected to herbivore exclusion exhibited lower defoliation rates and produced more acorns than control shoots. Defoliation constrained shoot growth throughout the study period, but had no effect on the number of female flowers produced per shoot. Acorn production was, however, lower in control shoots due to their higher abortion rates, and also to their greater mortality risk during summer drought, as shoots with fewer leaves were less likely to survive. Plant reaction to herbivory inhibits certain physiological pathways involved in plant growth, which, together with the effects of physical damage, reduces the amount and efficiency of the photosynthetic tissue. This increases their vulnerability to environmental stresses, such as water deficit, which limit resource assimilation. Defoliation is likely a key factor affecting oak regeneration, as it may be a significant source of seed loss prior to pre-dispersal acorn predation. Further experimental studies could help to elucidate its effects in contrasting environments. In Mediterranean regions, the harsher droughts predicted by climate change models could worsen the effects of insect herbivory on oak reproductive output., (© 2017 International Society of Zoological Sciences, Institute of Zoology/Chinese Academy of Sciences and John Wiley & Sons Australia, Ltd.)

Species introduced to habitats outside their native range often escape control by their natural enemies. Besides competing with native species, an alien species might also affect the native herbivores by introducing a new source of different quality food. Here, we describe the case of northern red oak (Quercus rubra) invasion in Europe. We collected data on insect (moth Cydia spp. and weevil Curculio spp.) seed predation of northern red oak in its native (USA, North America) and invasive (Poland, Europe) range, as well as for sessile oaks (Quercus petrea) in Europe. We also evaluated the quality of acorns as hosts for weevil larvae by collecting infested acorns and measuring weevil developmental success, and quantifying acorn traits such as seed mass, tannins, lipids and protein concentration. We used DNA barcoding to identify insects to the species level. The predation by moths was similar and very low in both species and in both ranges. However, red oaks escape pre-dispersal seed predation by weevils in Europe. Weevil infestation rates of northern red oak acorns in their invasive range were 10 times lower than that of sessile oaks, and also 10 times lower than that of red oaks in North America. Furthermore, even when weevils oviposited into northern red oaks, the larvae failed to develop, suggesting that the exotic host created a trap for the insect. This phenomenon might gradually decrease the local abundance of the seed predator, and further aid the invasion., (© 2017 International Society of Zoological Sciences, Institute of Zoology/Chinese Academy of Sciences and John Wiley & Sons Australia, Ltd.)

The function and conservation of many forest ecosystems depend on the distribution and diversity of the community of rodents that consume and disperse seeds. The habitat preferences and interactions are especially relevant in alpine systems where such granivorous rodents reach the southernmost limit of their distribution and are especially sensitive to global warming. We analyzed the community of granivorous rodents in the Pyrenees, one of the southernmost mountain ranges of Europe. Rodent species were identified by DNA with particular attention to the Apodemus species, which are prominent seed-dispersing rodents in Europe. We confirmed for the first time the presence of the yellow-necked mouse, Apodemus flavicollis, in central Pyrenees, a typical Eurosiberian species that reaches its southernmost distribution limit in this area. We also found the wood mouse, Apodemus sylvaticus, a related species more tolerant to Mediterranean environments. Both rodents were spatially segregated by altitude. A. sylvaticus was rare at high altitudes, which might cause the genetic differentiation between populations of the different valleys reported here. We also found other seed consumers like dormice, Elyomis quercinus, and voles, Myodes glareolus, with marked habitat preferences. We suggest that population isolation among valleys may increase the genetic diversity of rodents, like A. sylvaticus. We also highlight the potential threat that global warming may represent for species linked to high-altitude refuges at the southern edge of its distribution, like Apodemus flavicollis. Finally, we discuss how this threat may have a dimension in the conservation of alpine forests dispersed by these rodent populations., (© 2018 International Society of Zoological Sciences, Institute of Zoology/Chinese Academy of Sciences and John Wiley & Sons Australia, Ltd.)

Synchrony between seed growth and oogenesis is suggested to largely shape trophic breadth of seed-feeding insects and ultimately to contribute to their co-existence by means of resource partitioning or in the time when infestation occurs. Here we investigated: (i) the role of seed phenology and sexual maturation of females in the host specificity of seed-feeding weevils (Curculio spp.) predating in hazel and oak mixed forests; and (ii) the consequences that trophic breadth and host distribution have in the genetic structure of the weevil populations. DNA analyses were used to establish unequivocally host specificity and to determine the population genetic structure. We identified 4 species with different specificity, namely Curculio nucum females matured earlier and infested a unique host (hazelnuts, Corylus avellana) while 3 species (Curculio venosus, Curculio glandium and Curculio elephas) predated upon the acorns of the 2 oaks (Quercus ilex and Quercus pubescens). The high specificity of C. nucum coupled with a more discontinuous distribution of hazel trees resulted in a significant genetic structure among sites. In addition, the presence of an excess of local rare haplotypes indicated that C. nucum populations went through genetic expansion after recent bottlenecks. Conversely, these effects were not observed in the more generalist Curculio glandium predating upon oaks. Ultimately, co-existence of weevil species in this multi-host-parasite system is influenced by both resource and time partitioning. To what extent the restriction in gene flow among C. nucum populations may have negative consequences for their persistence in a time of increasing disturbances (e.g. drought in Mediterranean areas) deserves further research., (© 2017 The Authors. Integrative Zoology published by International Society of Zoological Sciences, Institute of Zoology/Chinese Academy of Sciences and John Wiley & Sons Australia, Ltd.)

The quick spread of the chestnut gall wasp Dryocosmus kuriphilus in Europe constitutes an outstanding example of recent human-aided biological invasion with dramatic economic losses. We screened for the first time a set of five nuclear and mitochondrial genes from D. kuriphilus collected in the Iberian Peninsula, and compared the sequences with those available from the native and invasive range of the species. We found no genetic variability in Iberia in none of the five genes, moreover, the three genes compared with other European samples showed no variability either. We recorded four cytochrome b haplotypes in Europe; one was genuine mitochondrial DNA and the rest nuclear copies of mitDNA (numts), what stresses the need of careful in silico analyses. The numts formed a separate cluster in the gene tree and at least two of them might be orthologous, what suggests that the invasion might have started with more than one individual. Our results point at a low initial population size in Europe followed by a quick population growth. Future studies assessing the expansion of this pest should include a large number of sampling sites and use powerful nuclear markers (e. g. Single Nucleotide Polymorphisms) to detect genetic variability.

Variation in seed availability shapes plant communities, and is strongly affected by seed predation. In some plant species, temporal variation in seed production is especially high and synchronized over large areas, which is called 'mast seeding'. One selective advantage of this phenomenon is predator satiation which posits that masting helps plants escape seed predation through starvation of predators in lean years, and satiation in mast years. However, even though seed predation can be predicted to have a strong spatial component and depend on plant densities, whether the effectiveness of predator satiation in masting plants changes according to the Janzen-Connell effect has been barely investigated. We studied, over an 8-year period, the seed production, the spatiotemporal patters of weevil seed predation, and the abundance of adult weevils in a holm oak (Quercus ilex) population that consists of trees interspersed at patches covering a continuum of conspecific density. Isolated oaks effectively satiate predators, but this is trumped by increasing conspecific plant density. Lack of predator satiation in trees growing in dense patches was caused by re-distribution of insects among plants that likely attenuated them against food shortage in lean years, and changed the type of weevil functional response from type II in isolated trees to type III in trees growing in dense patches. This study provides the first empirical evaluation of the notion that masting and predator satiation should be more important in populations that start to dominate their communities, and is consistent with the observation that masting is less frequent and less intense in diverse forests.

Masting is the highly variable production of synchronized seed crops, and is a common reproductive strategy in plants. Weather has long been recognized as centrally involved in driving seed production in masting plants. However, the theory behind mechanisms connecting weather and seeding variation has only recently been developed, and still lacks empirical evaluation. We used 12-year long seed production data for 255 holm oaks ( Quercus ilex ), as well as airborne pollen and meteorological data, and tested whether masting is driven by environmental constraints: phenological synchrony and associated pollination efficiency, and drought-related acorn abscission. We found that warm springs resulted in short pollen seasons, and length of the pollen seasons was negatively related to acorn production, supporting the phenological synchrony hypothesis. Furthermore, the relationship between phenological synchrony and acorn production was modulated by spring drought, and effects of environmental vetoes on seed production were dependent on last year's environmental constraint, implying passive resource storage. Both vetoes affected among-tree synchrony in seed production. Finally, precipitation preceding acorn maturation was positively related to seed production, mitigating apparent resource depletion following high crop production in the previous year. These results provide new insights into mechanisms beyond widely reported weather and seed production correlations., (© 2017 The Author(s).)

Host specialization has long been hypothesized to explain the extraordinary diversity of phytophagous insects in the tropics. However, addressing this hypothesis has proved challenging because of the risk of over-looking rare interactions, and hence biasing specialization estimations, and the difficulties to separate the diversity component attributable to insect specialization from that related to host diversity. As a result, the host specialization hypothesis lacks empirical support for important phytophagous insect clades. Here, we test the hypothesis in a radiation of seed-feeding insects, acorn weevils (Curculio spp.), sampled in temperate and tropical regions (California and Nicaragua, respectively) with an equivalent pool of oak host species. Using DNA sequences from three low-copy genes, we delimited to species level 778 weevil larvae extracted from host seeds and assessed their phylogenetic relationships by Maximum Likelihood and Bayesian inference. We then reconstructed the oak-weevil food webs and examined differences in alpha, beta and gamma diversity using Hill numbers of effective species. We found a higher alpha, beta and gamma diversity of weevils in Nicaragua compared to California despite similar richness of host species at both local and regional level. By means of Bayesian mixed models, we also found that tropical weevil species were highly specialized both in terms of host range and interaction strength, whereas their temperate congeners had a broader taxonomic and phylogenetic host spectrum. Finally, in Nicaraguan species, larval body size was highly correlated with the size of the acorns infested, as would be expected by a greater host specialization, whereas in California this relationship was absent. Altogether, these lines of evidence support the host specialization hypothesis and suggest contrasting eco-evolutionary dynamics in tropical and temperate regions even in absence of differences in host diversity., (© 2017 by the Ecological Society of America.)

Background and Aims: The geographical distributions of species are constrained by their ecological requirements. The aim of this work was to analyse the effects of environmental conditions, historical events and biogeographical constraints on the diversification of the three species of the western Mediterranean shrub genus Stauracanthus , which have a parapatric distribution in the Iberian Peninsula., Methods: Ecological niche factor analysis and generalized linear models were used to measure the response of all Stauracanthus species to the environmental gradients and map their potential distributions in the Iberian Peninsula. The bioclimatic niche overlap between the three species was determined by using Schoener's index. The genetic differentiation of the Iberian and northern African populations of Stauracanthus species was characterized with GenalEx. The effects on genetic distances of the most important environmental drivers were assessed through Mantel tests and non-metric multidimensional scaling., Key Results: The three Stauracanthus species show remarkably similar responses to climatic conditions. This supports the idea that all members of this recently diversified clade retain common adaptations to climate and consequently high levels of climatic niche overlap. This contrasts with the diverse edaphic requirements of Stauracanthus species. The populations of the S. genistoides-spectabilis clade grow on Miocene and Pliocene fine-textured sedimentary soils, whereas S. boivinii , the more genetically distant species, occurs on older and more coarse-textured sedimentary substrates. These patterns of diversification are largely consistent with a stochastic process of geographical range expansion and fragmentation coupled with niche evolution in the context of spatially complex environmental fluctuations., Conclusions: : The combined analysis of the distribution, realized environmental niche and phylogeographical relationships of parapatric species proposed in this work allows integration of the biogeographical, ecological and evolutionary processes driving the evolution of species adaptations and how they determine their current geographical ranges., (© The Author 2017. Published by Oxford University Press on behalf of the Annals of Botany Company. All rights reserved. For Permissions, please email: journals.permissions@oup.com)

We describe a novel species Cheiracanthium ilicis sp. n. (Araneae, Eutichuridae) collected in the province of Toledo (Central Spain). It was found during a systematic sampling campaign carried out in an agricultural landscape with isolated Holm oaks Quercus ilex and small forest patches. Its morphology and affinities with other species of the genus are discussed. Furthermore, one mitochondrial gene was sequenced to confirm species membership and its differentiation from other Cheiracanthium species. The molecular phylogenies based on mitochondrial and nuclear genes showed a close relationship of Cheiracanthium ilicis sp. n. with Cheiracanthium inclusum and Cheiracanthium mildei, with which it also shares morphological similarities. Nonetheless, the sparse sampling of the phylogeny, due to the low number of sequences available, impedes drawing any definitive conclusion about these relationships; it is first necessary to perform an extensive review of the genus worldwide and more thorough phylogenies. Cheiracanthium ilicis sp. n. also shares certain ecological and phenological characteristics with Cheiracanthium inclusum and Cheiracanthium mildei. Like them, Cheiracanthium ilicis sp. n. is an obligate tree dweller that prefers a tree canopy habitat and reproduces primarily in late spring and summer. From a conservation perspective, the present study suggests the need to preserve isolated trees in agricultural landscapes. They are not only the refuge of common forest organisms but also of novel species yet to be discovered.

The complexity of animal life histories makes it difficult to predict the consequences of climate change on their populations. In this paper, we show, for the first time, that longer summer drought episodes, such as those predicted for the dry Mediterranean region under climate change, may bias insect population sex ratio. Many Mediterranean organisms, like the weevil Curculio elephas, become active again after summer drought. This insect depends on late summer rainfall to soften the soil and allow adult emergence from their underground refuges. We found that, as in many protandric species, more C. elephas females emerged later in the season. Male emergence timing was on average earlier and also more dependent on the beginning of late summer rainfall. When these rains were delayed, the observed weevil sex ratio was biased towards females. So far, the effects of global warming on animal sex ratios has been reported for temperature-dependent sex determination in reptiles. Our results show that rainfall timing can also bias the sex ratio in an insect, and highlight the need for keeping a phenological perspective to predict the consequences of climate change. We must consider not just the magnitude of the predicted changes in temperature and rainfall but also the effects of their timing.

The patterns of seedling recruitment in animal-dispersed plants result from the interactions among environmental and behavioral variables. However, we know little on the contribution and combined effect of both kinds of variables. We designed a field study to assess the interplay between environment (vegetation structure, seed abundance, rodent abundance) and behavior (seed dispersal and predation by rodents, and rooting by wild boars), and their contribution to the spatial patterns of seedling recruitment in a Mediterranean mixed-oak forest. In a spatially explicit design, we monitored intensively all environmental and behavioral variables in fixed points at a small spatial scale from autumn to spring, as well as seedling emergence and survival. Our results revealed that the spatial patterns of seedling emergence were strongly related to acorn availability on the ground, but not by a facilitation effect of vegetation cover. Rodents changed seed shadows generated by mother trees by dispersing most seeds from shrubby to open areas, but the spatial patterns of acorn dispersal/predation had no direct effect on recruitment. By contrast, rodents had a strong impact on recruitment as pilferers of cached seeds. Rooting by wild boars also reduced recruitment by reducing seed abundance, but also by changing rodent's behavior towards higher consumption of acorns in situ. Hence, seed abundance and the foraging behavior of scatter-hoarding rodents and wild boars are driving the spatial patterns of seedling recruitment in this mature oak forest, rather than vegetation features. The contribution of vegetation to seedling recruitment (e.g. facilitation by shrubs) may be context dependent, having a little role in closed forests, or being overridden by directed seed dispersal from shrubby to open areas. We warn about the need of using broad approaches that consider the combined action of environment and behavior to improve our knowledge on the dynamics of natural regeneration in forests.

Trophic interactions can trigger the development of exaggerated specialized characters and promote morphological diversification. For example, acorn weevils (genus Curculio) present strikingly long rostrums, which are used by females to perforate oviposition holes through the seed coat. Species exhibiting longer rostrums are known to exploit larger acorns, and therefore rostrum length is thought to be subject to selection to match the preferred acorn type. However, rostrum length is strongly correlated with body size, and morphological divergence could result from either selection on rostrum length for optimal food exploitation or from other pressures acting on body size. We collected infested acorns at oak forests where the large Curculio elephas and the small-bodied Curculio glandium co-occur. There were no interspecific differences in adult female body size to rostrum length allometric relationships, and rostrum length is equally correlated with body size in either species. MtDNA-based species identification showed that C. glandium larvae were present within acorns of all sizes, whereas C. elephas larvae were restricted to acorns above a minimum size, irrespective of oak species. Hence, exploitation of large acorns can hardly have triggered rostrum enlargement, as the small sized C. glandium adults (with short rostrums) could perforate and oviposit in both small and large acorns. Rather, increased rostrum length is probably a by-product of the larger body sizes of individuals emerging from bigger acorns, which allow increased larval size and enhance larval survival likelihood. Summarizing, when exaggerated feeding traits co-vary with other body features, interspecific morphological variability may result from contrasting selective pressures acting on these correlated characters.

Hybridisation between species of the genus Quercus is a common phenomenon as a result of weak reproductive isolation mechanisms between phylogenetically close species that frequently co-occur in mixed stands. In this study, we use microsatellite markers to analyse introgression between kermes (Quercus coccifera L.) and holm (Q. ilex L.) oak, two closely related taxa that frequently dominate the landscape in extensive areas in the Mediterranean region. All tested microsatellites amplified and were polymorphic in both kermes and holm oaks. Bayesian admixture analyses showed a good correspondence between each species and one of the two inferred genetic clusters. Five sampled individuals were a priori tentatively identified as hybrids on the basis of intermediate morphological characteristics, and it was confirmed that they also presented mixed genotypes. However, we also detected different levels of genetic introgression among morphologically pure individuals, suggesting that successful backcrossing and/or reduced phenotypic expression of genetic variance in certain individuals may have resulted in strong convergence towards a single species phenotype.

Predators and parasitoids may contribute to controlling the population sizes of phytophagous insects, and this has been shown to benefit plants. Phytophagous insects may also be killed by other herbivores (intraguild predation), usually larger-sized vertebrates that ingest insects accidentally while feeding on common food sources. We studied the intraguild predation on acorn weevils by ungulates and assessed the consequences for weevil populations. Infested acorns are prematurely abscised and the weevil larvae finish their development inside the acorns after being dropped. Our results show that weevil larvae were killed by ungulates eating the infested acorns on the ground. Ungulates did not discriminate between infested and sound acorns, and the probability of a larva being incidentally eaten was inversely related to acorn availability. Thus, predation risk was enhanced by the premature drop of infested acorns when acorn availability on the ground was low. Predation rates on infested acorns were much higher where ungulates were present, and acorn infestation rates were significantly lower. However, ungulates did not provide the oaks any net benefit, since the reduction of infestation rates was not enough to compensate for the large amounts of sound acorns eaten by ungulates. Seed predation is usually studied as a progressive loss of seeds by pre- and post-dispersal predators, but the interactions between them are usually not considered. We show that intraguild predation on insects by large ungulates had an effect on the structure of the foraging guild, as the proportion of acorns predated by insects decreased; however, replicating the same experimental design in different ecological scenarios would increase the strength of these results. In conclusion, the present study shows the importance of considering the multi-trophic interactions between seed predators in order to have a complete picture of granivory.

Bird tails are extraordinarily variable in length and functionality. In some species, males have evolved exaggeratedly long tails as a result of sexual selection. Changes in tail length should be associated with changes in feather structure. The study of the evolution of feather structure in bird tails could give insight to understand the causes and means of evolution in relation to processes of sexual selection. In theory, three possible means of tail length evolution in relation to structural components might be expected: (1) a positive relationship between the increase in length and size of structural components maintaining the mechanical properties of the feather; (2) no relationship; that is, enlarging feather length without changes in the structural components; and (3) a negative relationship; that is, enlarging feather length by reducing structural components. These hypotheses were tested using phylogenetic analyses to examine changes in both degree of exaggeration in tail length and structural characteristics of tail feathers (rachis width and density of barbs) in 36 species, including those dimorphic and nondimorphic in tail length. The degree of sexual dimorphism in tail length was negatively correlated with both rachis width and density of barbs in males but not in females. Reinforcing this result, we found that dimorphism in tail length was negatively associated with dimorphism in tail feather structure (rachis width and density of barbs). These results support the third hypothesis, in which the evolution of long feathers occurs at the expense of making them simpler and therefore less costly to produce. However, we do not know the effects of enfeeblement on the costs of bearing. If the total costs increased, the enfeeblement of feathers could be explained as a reinforcement of the honesty of the signal. Alternatively, if total costs were reduced, the strategy could be explained by cheating processes. The study of female preferences for fragile tail feathers is essential to test these two hypotheses. Preferences for fragile tails would support the evolution of reinforcement of honesty, whereas female indifference would indicate the existence of cheating in certain stages of the evolutionary process.