Antagonistic interaction networks are structured independently of latitude and host guild

Peer reviewe

The identity of the Finnish Osmoderma (Coleoptera: Scarabaeidae, Cetoniinae) population established by COI sequencing

The hermit beetle Osmoderma eremita (Coleoptera: Scarabaeidae) is a flagship species for invertebrate conservation efforts by the European Union. This taxon has recently been revealed as a species complex likely encompassing five cryptic species. The northernmost population of Osmoderma is found on the island of Ruissalo in Turku, Finland. This population has been protected as species 0. eremita, but its true species affinity has never been established. To resolve its identity, we sequenced the mitochondrial COI gene from seven specimens sampled in Ruissalo. Based on a phylogenetic hypothesis generated from the sequences combined with previously published data, the Finnish hermit beetle was identified as Osmoderma barnabita. Information regarding the ecology and life cycle of 0. eremita should then not uncritically be assumed to apply to the Finnish population. Rather, the Finnish population should be treated as a separate entity in conservation and management of European Osmoderma

Disentangling the "brown world' faecal-detritus interaction web: dung beetle effects on soil microbial properties

Many ecosystem services are sustained by the combined action of microscopic and macroscopic organisms, and shaped by interactions between the two. However, studies tend to focus on only one of these two components. We combined the two by investigating the impact of macrofauna on microbial community composition and functioning in the context of a major ecosystem process: the decomposition of dung. We compared bacterial communities of pasture soil and experimental dung pats inhabited by one (Aphodius), two (Aphodius and Geotrupes), or no dung beetle genera. Overall, we found distinct microbial communities in soil and dung samples, and that the communities converged over the course of the experiment. Characterising the soil microbial communities underlying the dung pats revealed a significant interactive effect between the microflora and macrofauna, where the diversity and composition of microbial communities was significantly affected by the presence or absence of dung beetles. e specific identity of the beetles had no detectable impact, but the microbial evenness was lower in the presence of both Aphodius and Geotrupes than in the presence of Aphodius alone. Differences in microbial community composition were associated with differences in substrate usage as measured by Ecoplates. More-over, microbial communities with similar compositions showed more similar substrate usage. Our study suggests that the presence of macrofauna (dung beetles) will modify the microflora (bacteria) of both dung pats and pasture soil, including community diversity and functioning. In particular, the presence of dung beetles promotes the transfer of bacteria across the soil–dung interface, resulting in increased similarity in community structure and functioning. e results demonstrate that to understand how microbes contribute to the ecosystem process of dung decomposition, there is a need to understand their interactions with larger co-occurring fauna

Pellets of proof: First glimpse of the dietary composition of adult odonates as revealed by metabarcoding of feces

Recent advances in molecular techniques allow us to resolve the diet of unstudied taxa. Odonates are potentially important top-down regulators of many insects. Yet, to date, our knowledge of odonate prey use is based mainly on limited observations of odonates catching or eating their prey. In this study, we examine the potential use of metabarcoding in establishing the diet of three adult odonate species (Lestes sponsa, Enallagma cyathigerum, and Sympetrum danae) at a site in southwestern Finland. To this purpose, we compared three different methods for extracting DNA from fecal samples: the Macherey-Nagel Nucleospin XS kit, a traditional salt extraction, and the Zymo Research Fecal Microprep kit. From these extracts, we amplified group-specific mitochondrial markers (COI and 16S rRNA) from altogether 72 odonate individuals, and compared them to comprehensive reference libraries. The three odonate species show major overlap in diet, with no significant differences between individuals of different size and/or gender, reflecting opportunistic foraging of adult odonates. Of a total of 41 different prey species detected, the most frequently consumed ones were Diptera, with additional records of six other orders. Based on our data, the best DNA extraction method is the traditional salt extraction, as it provides the most information on prey content while also being the most economical. To our knowledge, this is the first study to resolve the species-level diet of adult odonates. Armed with the appropriate methodological caveats, we are ready to examine the ecological role of odonates in both terrestrial and aquatic food webs, and in transferring subsidies between these two realms

Data Integration in Genetics and Genomics: Methods and Challenges

Due to rapid technological advances, various types of genomic and proteomic data with different sizes, formats, and structures have become available. Among them are gene expression, single nucleotide polymorphism, copy number variation, and protein-protein/gene-gene interactions. Each of these distinct data types provides a different, partly independent and complementary, view of the whole genome. However, understanding functions of genes, proteins, and other aspects of the genome requires more information than provided by each of the datasets. Integrating data from different sources is, therefore, an important part of current research in genomics and proteomics. Data integration also plays important roles in combining clinical, environmental, and demographic data with high-throughput genomic data. Nevertheless, the concept of data integration is not well defined in the literature and it may mean different things to different researchers. In this paper, we first propose a conceptual framework for integrating genetic, genomic, and proteomic data. The framework captures fundamental aspects of data integration and is developed taking the key steps in genetic, genomic, and proteomic data fusion. Secondly, we provide a review of some of the most commonly used current methods and approaches for combining genomic data with focus on the statistical aspects

Unveiling the complexity and ecological function of aquatic macrophyte–animal networks in coastal ecosystems

Network theory offers innovative tools to explore the complex ecological mechanisms regulating species associations and interactions. Although interest in ecological networks has grown steadily during the last two decades, the application of network approaches has been unequally distributed across different study systems: while some kinds of interactions (e.g. plant-pollinator and host-parasite) have been extensively investigated, others remain relatively unexplored. Among the latter, aquatic macrophyte-animal associations in coastal environments have been largely neglected, despite their major role in littoral ecosystems. The ubiquity of macrophyte systems, their accessibility and multi-faceted ecological, economical and societal importance make macrophyte-animal systems an ideal subject for ecological network science. In fact, macrophyte-animal networks offer an aquatic counterpart to terrestrial plant-animal networks. In this review, we show how the application of network analysis to aquatic macrophyte-animal associations has the potential to broaden our understanding of how coastal ecosystems function. Network analysis can also provide a key to understanding how such ecosystems will respond to on-going and future threats from anthropogenic disturbance and environmental change. For this, we: (i) identify key issues that have limited the application of network theory and modelling to aquatic animal-macrophyte associations; (ii) illustrate through examples based on empirical data how network analysis can offer new insights on the complexity and functioning of coastal ecosystems; and (iii) provide suggestions for how to design future studies and establish this new research line into network ecology

Evidence for geographic substructuring of mtDNA variation in the East European Hermit beetle (Osmoderma barnabita)

The genus Osmoderma is a flagship taxon of invertebrate conservation in Europe and encompasses a complex of four accepted species. While species limits amongst Osmoderma have been intensively studied, patterns of intraspecific variation are poorly known. In this paper, the authors focus on clarifying the phylogeographic structure of the East European Osmoderma barnabita using samples from Croatia to Finland. Samples of hind legs were collected from populations in Latvia and Finland (n=186) and combined with previously-published sequences from GenBank and museum specimens (n=10). In a partial sequence of the mitochondrial COI gene (759 bp), 26 closely related haplotypes were found. Beetle samples from different parts of Europe were distinct and showed no overlap in haplotype composition. The solitary population of Finland proved to be monomorphic and all 97 individuals sampled here belonged to a single haplotype unique to this region. The results suggest the Northern parts of Eastern Europe to be dominated by a single COI haplotype to which most of the other haplotypes are linked by one or two mutations. The pattern seems to reflect a founder effect or a strong bottleneck event. While O. barnabita is widely distributed over Eastern Europe, current patterns of mitochondrial genetic diversity appear influenced by population history and little homogenisation by ongoing gene flow. From a conservation perspective, the patterns suggest that regional populations might need to be managed as subunits and that the population of Finland may be affected by low genetic diversity

A network approach for managing ecosystem services and improving food and nutrition security on smallholder farms

Smallholder farmers are some of the poorest and most food insecure people on Earth. Their high nutritional and economic reliance on home-grown produce makes them particularly vulnerable to environmental stressors such as pollinator loss or climate change which threaten agricultural productivity. Improving smallholder agriculture in a way that is environmentally sustainable and resilient to climate change is a key challenge of the 21st century. Ecological intensification, whereby ecosystem services are managed to increase agricultural productivity, is a promising solution for smallholders. However, smallholder farms are complex socio-ecological systems with a range of social, ecological and environmental factors interacting to influence ecosystem service provisioning. To truly understand the functioning of a smallholder farm and identify the most effective management options to support household food and nutrition security, a holistic, systems-based understanding is required. In this paper, we propose a network approach to understand, visualise and model the complex interactions occurring among wild species, crops and people on smallholder farms. Specifically, we demonstrate how networks may be used to (a) identify wild species with a key role in supporting, delivering or increasing the resilience of an ecosystem service; (b) quantify the value of an ecosystem service in a way that is relevant to the food and nutrition security of smallholders; and (c) understand the social interactions that influence the management of shared ecosystem services. Using a case study based on data from rural Nepal, we demonstrate how this framework can be used to connect wild plants, pollinators and crops to key nutrients consumed by humans. This allows us to quantify the nutritional value of an ecosystem service and identify the wild plants and pollinators involved in its provision, as well as providing a framework to predict the effects of environmental change on human nutrition. Our framework identifies mechanistic links between ecosystem services and the nutrients consumed by smallholder farmers and highlights social factors that may influence the management of these services. Applying this framework to smallholder farms in a range of socio-ecological contexts may provide new, sustainable and equitable solutions to smallholder food and nutrition security. A free Plain Language Summary can be found within the Supporting Information of this article

Crop diversity benefits carabid and pollinator communities in landscapes with semi-natural habitats

In agricultural landscapes, arthropods provide essential ecosystem services such as biological pest control and pollination. Intensified crop management practices and homogenization of landscapes have led to declines among such organisms. Semi-natural habitats, associated with high numbers of these organisms, are increasingly lost from agricultural landscapes but diversification by increasing crop diversity has been proposed as a way to reverse observed arthropod declines and thus restore ecosystem services. However, whether or not an increase in the diversity of crop types within a landscape promotes diversity and abundances of pollinating and predaceous arthropods, and how semi-natural habitats might modify this relationship, are not well understood. To test how crop diversity and the proportion of semi-natural habitats within a landscape are related to the diversity and abundance of beneficial arthropod communities, we collected primary data from seven studies focusing on natural enemies (carabids and spiders) and pollinators (bees and hoverflies) from 154 crop fields in Southern Sweden between 2007 and 2017. Crop diversity within a 1-km radius around each field was positively related to the Shannon diversity index of carabid and pollinator communities in landscapes rich in semi-natural habitats. Abundances were mainly affected by the proportion of semi-natural habitats in the landscape, with decreasing carabid and increasing pollinator numbers as the proportion of this habitat type increased. Spiders showed no response to either crop diversity or the proportion of semi-natural habitats. Synthesis and applications. We show that the joint effort of preserving semi-natural habitats and promoting crop diversity in agricultural landscapes is necessary to enhance communities of natural enemies and pollinators. Our results suggest that increasing the diversity of crop types can contribute to the conservation of service-providing arthropod communities, particularly if the diversification of crops targets complex landscapes with a high proportion of semi-natural habitats

Threats from the air: Damselfly predation on diverse prey taxa

To understand the diversity and strength of predation in natural communities, researchers must quantify the total amount of prey species in the diet of predators. Metabarcoding approaches have allowed widespread characterization of predator diets with high taxonomic resolution. To determine the wider impacts of predators, researchers should combine DNA techniques with estimates of population size of predators using mark-release-recapture (MRR) methods, and with accurate metrics of food consumption by individuals.Herein, we estimate the scale of predation exerted by four damselfly species on diverse prey taxa within a well-defined 12-ha study area, resolving the prey species of individual damselflies, to what extent the diets of predatory species overlap, and which fraction of the main prey populations are consumed.We identify the taxonomic composition of diets using DNA metabarcoding and quantify damselfly population sizes by MRR. We also use predator-specific estimates of consumption rates, and independent data on prey emergence rates to estimate the collective predation pressure summed over all prey taxa and specific to their main prey (non-biting midges or chironomids) of the four damselfly species.The four damselfly species collectively consumed a prey mass equivalent to roughly 870 (95% CL 410-1,800) g, over 2 months. Each individual consumed 29%-66% (95% CL 9.4-123) of its body weight during its relatively short life span (2.1-4.7 days; 95% CL 0.74-7.9) in the focal population. This predation pressure was widely distributed across the local invertebrate prey community, including 4 classes, 19 orders and c. 140 genera. Different predator species showed extensive overlap in diets, with an average of 30% of prey shared by at least two predator species.Of the available prey individuals in the widely consumed family Chironomidae, only a relatively small proportion (0.76%; 95% CL 0.35%-1.61%) were consumed.Our synthesis of population sizes, per-capita consumption rates and taxonomic distribution of diets identifies damselflies as a comparatively minor predator group of aerial insects. As the next step, we should add estimates of predation by larger odonate species, and experimental removal of odonates, thereby establishing the full impact of odonate predation on prey communities