Most work on plant community ecology has been performed above ground, neglecting the processes that occur in the soil. DNA metabarcoding, in which multiple species are computationally identified in bulk samples, can help to overcome the logistical limitations involved in sampling plant communities belowground. However, a major limitation of this methodology is the quantification of species’ abundances based on the percentage of sequences assigned to each taxon. Using root tissues of five dominant species in a semi‐arid Mediterranean shrubland (Bupleurum fruticescens, Helianthemum cinereum, Linum suffruticosum, Stipa pennata and Thymus vulgaris), we built pairwise mixtures of relative abundance (20%, 50% and 80% biomass), and implemented two methods (linear model fits and correction indices) to improve estimates of root biomass. We validated both methods with multispecies mixtures that simulate field‐collected samples. For all species, we found a positive and highly significant relationship between the percentage of sequences and biomass in the mixtures (R2 = .44–.66), but the equations for each species (slope and intercept) differed among them, and two species were consistently over‐ and under‐estimated. The correction indices greatly improved the estimates of biomass percentage for all five species in the multispecies mixtures, and reduced the overall error from 17% to 6%. Our results show that, through the use of post‐sequencing quantification methods on mock communities, DNA metabarcoding can be effectively used to determine not only species’ presence but also their relative abundance in field samples of root mixtures. Importantly, knowledge of these aspects will allow us to study key, yet poorly understood, belowground processes.

This work combines state-of-the-art methods (DNA metabarcoding) with classic approaches (visual stomach content characterization and stable isotope analyses of nitrogen (δ15N) and carbon (δ13C)) to investigate the trophic ecology of anchovy (Engraulis encrasicolus) and sardine (Sardina pilchardus) at high taxonomic and spatial resolution in the Western Mediterranean Sea. Gut contents observed are in accordance with the dietary plasticity generally described for anchovy and sardine, suggesting a diet related to the opportunistic ingestion of available prey in a certain area and/or time. Genetic tools also showed modest inter-specific differences regarding ingested species. However, inter-specific and intra-specific differences in ingested prey frequencies and prey biomass reflected a latitudinal signal that could indicate a more effective predation on large prey like krill by anchovy versus sardine, as well as a generalized higher large prey ingestion by both species southwards. In fact, both species presented lower δ15N in the northernmost area. This latitudinal gradient indicates changes in the trophic ecology of anchovy and sardine that coincide with previously described better biological conditions for fish in the southern part of the study area as well as higher landings of both species in recent years.

Flightless, phoretic insects of the tribe Meloini include several widespread species able to inhabit both mainland and oceanic and continental islands. Relationships between phoretic and non‐phoretic species of Meloini are unclear, precluding broad evolutionary and biogeographic analyses within the group. We provide a robust molecular phylogenetic framework for Meloini, with finer sampling in the Western Palaearctic, by analysing two nuclear (Wg, 18S) and two mtDNA (cox1, 16S) gene fragments of 24 species representing eight subgenera of Meloe and Physomeloe. Our phylogenetic analyses revealed that Meloe, as currently recognized, is paraphyletic. Our phylogenetic hypothesis clarifies several controversial relationships within the group. We provide a new taxonomic framework that better reflects the evolutionary relationships of the group by raising to genus all previously considered subgenera: Afromeloe Schmidt, 1913, Alveomeloe Pripisnova, 1987, Chiromeloe Reitter, 1911, Desertimeloe Kaszab, 1964, Eurymeloe Reitter, 1911, Lampromeloe Reitter, 1911, Lasiomeloe Reitter, 1911, Listromeloe Reitter, 1911, Meloegonius Reitter, 1911, Mesomeloe Reitter, 1911, Meloenellus Reitter, 1911, Micromeloe Reitter, 1911, Taphromeloe Reitter, 1911 and Treiodous Dugès, 1869; while Anchomeloe Iablokoff‐Khnzorian, 1983, is recovered as subgenus of Meloe. In addition, we conducted an extensive intraspecific sampling for four phoretic taxa (Meloe proscarabaeus, Meloe autumnalis, Eurymeloe mediterraneus and Eurymeloe tuccia) and used mtDNA phylogeographic analyses to unveil patterns of overseas dispersal. Our phylogeographic analyses revealed a high level of geographically unstructured haplotype diversity within taxa, suggesting that transmarine dispersal events have occurred multiple times along the evolutionary history of phoretic species of blister beetles. Larval phoresy may explain the existence of idiosyncratic biogeographic and phylogeographic patterns in these flightless organisms.

The phylogeography of montane species often reveals strong genetic differentiation among mountain ranges. Both classic morphological and genetic studies have indicated distinctiveness of Pyrenean populations of the butterfly Erebia euryale. This hypothesis remained inconclusive until data from the westernmost populations of the distribution area (Cantabrian Mountains) were analysed. In the present study, we set out to describe the population structure of Erebia euryale in western Cantabria, where the species occurs in scattered localities. For this goal, we estimate the genetic diversity and differentiation found in 218 individuals from six Cantabrian (North Spain) localities genotyped by 17 allozyme loci. We also sequence 816 bp of the cytochrome oxidase subunit I mitochondrial gene in 49 individuals from Cantabrian localities and 41 specimens from five other European sites. Mitochondrial data support the recognition of four major genetic groups previously suggested for the European populations based on allozyme polymorphisms. Both mitochondrial and nuclear markers reveal genetic distinctiveness of a single PyreneanCantabrian lineage of E. euryale. The lack of geographical structure and the star-like topology displayed by the mitochondrial haplotypes indicate a pattern of demographic expansion in northern Iberia, probably related to Upper Pleistocene climatic oscillations. By contrast, within the Pyrenean-Cantabrian lineage, Cantabrian samples are genetically structured in nuclear datasets. In particular, San Isidro is significantly differentiated from the other five populations, which cluster into two groups. We recognize an evolutionary significant unit for PyreneanCantabrian populations of Erebia euryale. Our results also illustrate that the evolutionary history of a species may be shaped by processes undetectable by using mtDNA alone.

Sex attractant pheromones are highly sensitive and selective tools for detecting and monitoring populations of insects, yet there has been only one reported case of pheromones being used to monitor protected species. Here, we report the identification and synthesis of the sex pheromone of a protected European moth species, Graellsia isabellae (Lepidoptera: Saturniidae), as the single component, (4E,6E,11Z)-hexadecatrienal. In preliminary field trials, lures loaded with this compound attracted male moths from populations of this species at a number of widely separated field sites in France, Switzerland, and Spain, clearly demonstrating the utility of pheromones in sampling potentially endangered insect species.Electronic supplementary materialThe online version of this article (doi:10.1007/s10886-010-9831-1) contains supplementary material, which is available to authorized users.