Three people's view of the future of gall research

At the 25th anniversary of the British Plant Gall Society three colleagues who have been working for more than 20 years with cynipid gall systems provide a broad view of what has happened in the field and what questions might be most interesting for the near future to tackle. They fall broadly in five areas: How do they induce galls? How did galling evolve? Why do galls come in such amazing shapes and sizes? And how can we tell the inhabitants apart

Guidance for interpretation of CBD categories on introduction pathways

Technical note prepared by IUCN for the European Commission. This note has been drafted by a team of experts under the supervision of IUCN within the framework of the contract No 07.0202/2016/739524/SER/ENV.D.2 “Technical and Scientific support in relation to the Implementation of Regulation 1143/2014 on Invasive Alien Species”

PIPITS: an automated pipeline for analyses of fungal internal transcribed spacer sequences from the Illumina sequencing platform

1. Studying fungal biodiversit y using data generated from Illumina MiSeq sequencing platforms poses a number of bioinformatic challenges with the analysis typically involving a large number of tools for each analytical step from quality filtering to generating identified operational taxonomic unit (OTU) abundance tables. 2. Here, we introduce PIPITS, an o pen-source stand-alone suite of software for automated processing of Illumina MiSeq sequences for fungal community analysis. PIPITS e xploits a number of state of the art applications to process paired-end reads from quality filtering to producing OTU abundance tables. 3. We pro vide detailed descriptions of the pipeline and show its utility in the analysis of 9 396 092 sequences generated on the MiSeq platform from Illumina MiSeq. 4. PIPITS is the first automated bioinformatics pipeline dedicated for fungal ITS sequences which incorporates ITSx to extract subregions of ITS and exploits the latest RDP Classifier to classify sequences against the curatedUNITE fungal data set

Top-down network analysis characterizes hidden termite–termite interactions

The analysis of ecological networks is generally bottom-up, where networks are established by observing interactions between individuals. Emergent network properties have been indicated to reflect the dominant mode of interactions in communities that might be mutualistic (e.g., pollination) or antagonistic (e.g., host–parasitoid communities). Many ecological communities, however, comprise species interactions that are difficult to observe directly. Here, we propose that a comparison of the emergent properties from detail-rich reference communities with known modes of interaction can inform our understanding of detail-sparse focal communities. With this top-down approach, we consider patterns of coexistence between termite species that live as guests in mounds built by other host termite species as a case in point. Termite societies are extremely sensitive to perturbations, which precludes determining the nature of their interactions through direct observations. We perform a literature review to construct two networks representing termite mound cohabitation in a Brazilian savanna and in the tropical forest of Cameroon. We contrast the properties of these cohabitation networks with a total of 197 geographically diverse mutualistic plant–pollinator and antagonistic host–parasitoid networks. We analyze network properties for the networks, perform a principal components analysis (PCA), and compute the Mahalanobis distance of the termite networks to the cloud of mutualistic and antagonistic networks to assess the extent to which the termite networks overlap with the properties of the reference networks. Both termite networks overlap more closely with the mutualistic plant–pollinator communities than the antagonistic host–parasitoid communities, although the Brazilian community overlap with mutualistic communities is stronger. The analysis raises the hypothesis that termite–termite cohabitation networks may be overall mutualistic. More broadly, this work provides support for the argument that cryptic communities may be analyzed via comparison to well-characterized communities

Acoustic communication within ant societies and its mimicry by mutualistic and socially parasitic myrmecophiles

This review focuses on the main acoustic adaptations that have evolved to enhance social communication in ants. We also describe how other invertebrates mimic these acoustic signals in order to coexist with ants in the case of mutualistic myrmecophiles, or, in the case of social parasites, corrupt them in order to infiltrate ant societies and exploit their resources. New data suggest that the strength of each ant myrmecophile interaction leads to distinctive sound profiles and may be a better predictor of the similarity of sound between different myrmecophilous species than their phylogenetic distance. Finally, we discuss the evolutionary significance of vibrations produced by specialized myrmecophiles in the context of ant multimodal communication involving the use of chemical and acoustic signals in combination and identify future challenges for research including how new technology might allow a better understanding of the study systems

Individual tree traits shape insect and disease damage on oak in a climate-matching tree diversity experiment

Diversifying planted forests by increasing genetic and species diversity is often promoted as a method to improve forest resilience to climate change and reduce pest and pathogen damage. In this study we used a young tree diversity experiment replicated at two sites in the UK to study the impacts of tree diversity and tree provenance (geographic origin) on the oak (Quercus robur) insect herbivore community and a specialist biotrophic pathogen, oak powdery mildew. Local UK, French and Italian provenances were planted in monocultures, provenance mixtures and species mixes, allowing us to test whether: 1) local and non-local provenances differ in their insect herbivore and pathogen communities, and 2) admixing trees leads to associational effects on insect herbivore and pathogen damage. Tree diversity had variable impacts on foliar organisms across sites and years, suggesting that diversity effects can be highly dependent on environmental context. Provenance identity impacted upon both herbivores and powdery mildew, but we did not find consistent support for the local adaptation hypothesis for any group of organisms studied. Independent of provenance, we found tree vigour traits (shoot length, tree height) and tree apparency (the height of focal trees relative to their surroundings) were consistent positive predictors of powdery mildew and insect herbivory. Synthesis. Our results have implications for understanding the complex interplay between tree identity and diversity in determining pest damage, and show that tree traits, partially influenced by tree genotype, can be important drivers of tree pest and pathogen loads

Structure and composition of tritrophic communities associated with Fagaceae-feeding cynipid gallwasps in Sichuan, China

We provide the first description and analysis of species-rich communities of Fagaceae host plants, cynipid gall inducers and Hymenopteran parasitoids from two sites in western Sichuan, China. We use quantified interaction data to test the hypothesis that metabolically intimate cynipid-Fagaceae interactions are more specialised, resulting in more modular networks and stronger signatures of turnover than nestedness for beta diversity, than associations between parasitoids and Fagaceae. Rearing of nearly 27,000 cynipid gall specimens from 22 host plant species in Castanea, Castanopsis, Lithocarpus and Quercus (sections Cerris, Cyclobalanopsis, Ilex and Quercus) yielded 168 morphologically distinct cynipid gall morphotypes, and 3800 parasitoids in 67 morphospecies. The Sichuan parasitoid assemblage is similar in composition to cynipid-centred communities in the Western Palearctic and Nearctic. All of our predictions were confirmed. We discuss our findings in light of the processes thought to structure tritrophic interactions centred on gall inducing insect herbivores

Host specificity pattern and chemical deception in a social parasite of ants

In natural ecosystems, relationships between organisms are often characterised by high levels of complexity, where vulnerabilities in multi-trophic systems are difficult to identify, yet variation in specific community modules can be traceable. Within the complex community interactions, we can shed new light on dynamics by which co-evolutionary outcomes can inform science-led conservation. Here we assessed host-ant use in six populations of the butterfly Phengaris (=Maculinea) rebeli, an obligate social parasite of Myrmica ants and a model system in evolutionary and conservation ecology. Starting from the initial distribution of eggs, we estimated the survival of the parasite in the wild in nests of seven Myrmica ant species, and analysed the chemical cues evolved by the parasites to subvert its host defences. We found local variations in host specificity that are consistent with similarities found in the chemical profiles of hosts and parasites on different sites. At some sites, only one ant species is successfully exploited; at others, multiple-host populations are used. Understanding how stable or adaptable these associations are is essential knowledge when devising conservation measures to maintain keystone species of ant and locally adapted populations of Phengaris butterfly species, which are rare, threatened and a high priority for conservation worldwide

Invasive alien species – framework for the identification of invasive alien species of EU concern

Invasive alien species (IAS) are considered to be one of the greatest threats to biodiversity, particularly through their interactions with other drivers of change (MEA 2005, GBO 2011). In recent years the European Commission (EC) has intensified their commitment to provide a comprehensive, problem-oriented, well-balanced and manageable solution to IAS in Europe. The text of a European Union (EU) Regulation is expected to be adopted soon. A core component of the Regulation is a list of “IAS of EU concern” that will be drawn up together with European Member States (MS), based on scientifically robust risk assessments as laid down in the Regulation. Risk assessment is the technical and objective process of evaluating biological or other scientific and economic evidence to identify potentially invasive alien species and determine the level of invasion risk associated with a species or pathway and specifically whether an alien species will become invasive. An effective and robust risk assessment method is seen as an essential component of IAS management (Shine, Kettunen et al. 2010) and a fundamental element of an early warning and information system in Europe (Genovesi, Scalera et al. 2010). The purpose of this project was to provide a review of available IAS risk analysis protocols and use this, coupled with expert opinion, to inform the development of minimum standards necessary to ensure effective risk assessment methods for the EU. Additionally we considered gaps in knowledge and scope of existing risk analysis methods. Thus, we provide recommendations for developing existing risk analysis methods within a framework of minimum standards. Methods compliant with the minimum standards will be of value for supporting the development of a draft list of “IAS of EU concern”. Such a list should include species that are already established within the EU but also be extended to a scoping study to consider species that are not yet established but that may present a significant threat to Europe in the near future. Task 1: Literature review and critical assessment of existing risk assessment methodologies on IAS The purpose of the review was to critically assess the scope, robustness and effectiveness of current risk assessment methods and to provide information for their further development in the context of the study particularly underpinning the derivation of minimum standards. More than 100 relevant publications were derived through a literature search. Only 70 publications provided original risk assessment protocols and their applications and of these 29 were selected through filtering to eliminate those which simply described the implementation of an existing protocol to a given geographic region or specific taxonomic groups without modification of the assessment protocol. These 29 protocols were examined further to derive key attributes of the risk assessment method to inform the development of minimum standards. Basic information for all 29 risk assessment methods was provided. Case studies for 14 of these protocols were included to provide further context for subsequent tasks. The 14 protocols included as case studies were selected on the basis of a number of criteria: relevance of the protocol to Europe, taxonomic breadth and/or geographic breadth, likely compliance with minimum standards and availability of experts with key involvement in the protocol to provide the case study. At both the international and regional-level as well as among countries, there is huge variation in how the risks posed by alien species are assessed. Indeed risk assessment protocols vary widely in approach, objective, implementation and taxa covered, the majority are based on qualitative methods, even though the need to develop quantitative risk assessments has been recognised. Major hurdles preventing the use of quantitative risk assessment methods are the lack of data and challenges in interpretation and communication. Two critical gaps were identified through this task: consideration of ecosystem services and evaluation of user-friendliness and consistency of outcomes. Very few risk assessment protocols reviewed specifically considered impacts on ecosystem services. Consistency in risk analysis has been recently discussed and assessed for pest risk analyses in the EU-funded project PRATIQUE and methods to improve consistency have been developed. PRATIQUE only considered the EPPO decision support scheme (EPPO DSS), however this work will be extended through consideration of additional risk assessments within the current EU-funded COST Action Alien Challenge. Task 2: Develop minimum standards for risk assessment methodologies The review of characteristics of risk assessments through task 1 resulted in a long-list of attributes. The derived attributes ranged from broad consideration of general characteristics including description of the species through to criteria relevant to the invasion process including likelihood of arrival, establishment and spread. Impacts were classified broadly and included biodiversity and socio-economic impacts alongside perspectives influencing impacts such as climate change. Additional consideration was given to implementation of the protocol including quality assurance and alignment with agreed international standards and policies such as the World Trade Organisation (WTO) and relevant EU Directives including the EU Marine Strategy Framework Directive (MSFD) and EU Water Framework Directive (WFD). From the long-list the core project team developed and selected a draft short-list of attributes that were considered to be relevant for performing risk assessments of IAS. The short-list of minimum standards was agreed by the project team and preliminarily reviewed through a pre-workshop survey in Task 3. Task 3: Risk assessment workshop The overarching aim of the risk assessment workshop (27-28th March 2014) was to peer-review the derived short-list of minimum standards. The derived minimum standards are required to underpin evaluation of existing risk assessments and ensure they are fit for the purpose of supporting the development of a list of “IAS of EU concern”. We aimed to distil the critical components of a risk assessment that, through expert opinion and consensus, are agreed necessary to achieve overarching, robust and rigorous assessment of the risk of an IAS, regardless of the specific approach taken. Additionally consideration was given to recognized international guidelines and recommendations with relevance to the development of minimum standards for risk assessments. The workshop included participants from the project team (23 experts from nine organisations) and 12 additional invited experts. The invited experts and those from within the team represented a breadth of expertise from a variety of perspectives including taxonomic (all taxa, including pathogens), environmental (freshwater, marine and terrestrial), impacts (environmental, socio-economic and health) and disciplines (ecologists, economist, conservation practitioners, scientists, policy-makers, risk assessors). Many of the experts had been actively involved in the development, testing and implementation of risk assessment protocols for IAS. The experts were invited to review and refine the list of attributes derived through Tasks 1 and 2 for inclusion as potential minimum standards. The long list of attributes of risk assessments derived through Task 1 and 2 were circulated in the form of a pre-workshop survey (using Survey Monkey) in which the experts were asked to rank the importance of each as a potential minimum standard on a scale of 1 (low importance) to 5 (high importance). Experts were also asked to provide additional attributes that were not apparent from the long-list. The pre-workshop survey revealed a high level of consensus between all experts for most of the attributes. However one-third of the experts stated that a totally new EU-wide risk assessment system tailored for the new IAS Regulation should be developed. Attributes aligning with socio-economic aspects also appeared to cause division in responses by the experts. Furthermore, questions relating to cost-benefit led to a high degree of uncertainty with more than a third of participants responding “unsure”. The disagreement or uncertainty expressed by respondents on these specific themes highlighted the need to ensure that socio-economic considerations were included as a substantial component of the workshop programme. Clarity is an overarching requirement of risk assessment protocols to ensure consistency. It is of utmost importance that a protocol asks questions that are sufficiently clear and understandable for assessors. This is essential to ensure that responses (accompanied by an indication of level of uncertainty) deliver similar assessments for the same species in the same area, irrespective of the identity of the assessors – as long as these have the necessary expertise or are provided with the necessary information. Fourteen criteria were agreed, through consensus methods, to represent the minimum standards. The minimum standards are: 1. Description (Taxonomy, invasion history, distribution range (native and introduced), geographic scope, socio-economic benefits) 2. Includes the likelihood of entry, establishment, spread and magnitude of impact 3. Includes description of the actual and potential distribution, spread and magnitude of impact 4. Has the capacity to assess multiple pathways of entry and spread in the assessment, both intentional and unintentional 5. Can broadly assess environmental impact with respect to biodiversity and ecosystem patterns and processes 6. Can broadly assess environmental impact with respect to ecosystem services 7. Broadly assesses adverse socio-economic impact 8. Includes status (threatened or protected) of species or habitat under threat 9. Includes possible effects of climate change in the foreseeable future 10. Can be completed even when there is a lack of data or associated information 11. Documents information sources 12. Provides a summary of the different components of the assessment in a consistent and interpretable form and an overall summary 13. Includes uncertainty 14. Includes quality assurance Task 4: Screening of existing risk assessment methodologies None of the analysed risk assessment protocols were fully compliant with the minimum standards. However, there were a number of protocols that appeared to be compliant with a sufficient number of the minimum standards or with the potential to be modified in accordance with the minimum standards to be included within Task 4. The GB NNRA, EPPO DSS, Harmonia+ and ENSARS were the risk assessment protocols that most closely met the minimum standards, they are further referred to as "substantially compliant risk assessments". The risk assessments undertaken with the GB NNRA and EPPO DSS were accessible and included a range of species. Harmonia+ has potential as a risk assessment protocol with broad taxonomic and geographic applicability. It is a comprehensive risk assessment protocol, however it has only recently been published and currently no species have been formally assessed using this method. ENSARS includes assessments for a number of species but these are not yet formally published. GB NNRA and Harmonia+ both currently lack inclusion of description of socio-economic benefits. However, experts representing these methods acknowledge a willingness to include this aspect as a priority in the future. The EPPO DSS and ENSARS already consider such benefits. Consideration of possible effects on climate change in the foreseeable future was lacking in most protocols. However, the GB NNRA does include climate change considerations. ENSARS, Harmonia+ and EPPO fail to include climate change considerations within their protocols but could easily include this aspect as a priority for updates in the future. Consideration of the effects of IAS on ecosystem services was almost consistently lacking in the risk assessment protocols. This was identified through the literature review (Tasks 1 and 2) but was confirmed through Task 4. IAS impacts on biodiversity, ecosystem patterns and processes, ecosystem services and related socio-economic implications are clearly interlinked. Therefore, there are foreseen to be overlaps in how these different impacts are determined in practice: the identification of impacts on biodiversity and ecosystem characteristics clearly forms the basis for impacts on ecosystem services whereas identifying the impacts on ecosystem services form a key conceptual basis for assessing the foreseen socio-economic impacts of IAS invasion. These overlaps – or synergies - should be taken into consideration when developing these three minimum standards further in the future. It is foreseen that a dedicated guidance on how to assess the impact on ecosystem services, in the context of EU risk assessments for IAS, would need to be developed. Task 5: Screening of potential “IAS of EU Concern” and proposal of a list Prioritisation of potential “IAS of EU concern” is essential to both target IAS interventions at the species constituting the highest risks and for allocating the limited resources available for invasion management based on feasibility of outcomes. The establishment of a risk analysis framework, in consultation with the EC, would ensure a coherent and coordinated response to risks of EU relevance which could be termed “IAS of EU concern”. The main objective of the study was to analyse a set of species that have been risk assessed using protocols meeting the minimum standards to develop the list of “IAS of EU concern”. As a result of the analysis in Task 4, it was apparent that none of the existing protocols screened, tested and discussed within Task 3 meet the full set of minimum standards. We proceeded with the analysis of the list of 80 species provided by the Commission against those protocols for risk assessment that were considered as “substantially compliant”. Due to the lack of risk assessment protocols compliant with the minimum standards, it was not possible to obtain a fully compliant list of proposed “IAS of EU concern” as initially foreseen. However, four risk assessment protocols, namely the EPPO DSS, ENSARS, GB NNRA and Harmonia+, were selected as they meet “most” minimum standards and included a breadth of species in existing assessments. The lists generated from the four selected protocols were thus cross-tabulated against the list of 80 species provided by the EC. It is important to note that some of the existing assessments (most notably within GB NNRA, ENSARS and Harmonia+) apply to a restricted area within Europe and so caution in extrapolating outcomes to a European-scale is required. In total 50 species are included within the draft list of proposed “IAS of EU concern” and these were identified through the “substantially compliant” risk assessments as posing a medium to high risk on biodiversity and/or human health and the economy. Of these 37 are from GB NNRA, 18 from EPPO and one from ENSARS. Seven of the species were assessed within more than one protocol. The list includes 14 species in addition to those within the original list provided by the EC. The draft list of proposed “IAS of EU concern” includes 25 plants, 12 vertebrates, 13 invertebrates of which most are found in the terrestrial and freshwater environments (24 and 20 respectively whereas only six marine species are included). The draft list is constrained by inclusion of only the IAS for which a “substantially compliant” risk assessment is available. Furthermore, there are inherent limitations of a list of proposed “IAS of EU concern” compiled on the basis of risk assessment protocols which do not fully comply with the agreed minimum standards. This is reflected in a number of shortcomings or inconsistencies resulting from the outcomes of the four protocols which were used to draft the list of proposed “IAS of EU concern”. Concluding remarks and key recommendations Available risk assessment protocols that meet the minimum standards are an important step in developing a list of “IAS of EU concern”. Refinements to existing risk assessment protocols are required to ensure they include consideration of ecosystem services, climate change and adverse impacts on socio-economic benefits. As these criteria are encompassed it will be necessary to critically test and evaluate the performance of these modified protocols as it is necessary to improve consistency of outcomes. Support should be given to enable developments to modify risk assessment protocols within their mandate to comply with the new EU Regulation. This should include the development of appropriate guidance on the interpretation and use of minimum standards where required. Additionally the importance of national impact assessment protocols should be recognised with consideration given to modifications of methods to provide a scientific basis for EU assessments. These assessments should serve as source to identify potential additional ‘IAS of EU concern’ and evaluation of the list. Impact assessments are not compliant with the minimum standards because of lack of consideration of mechanisms of introduction and establishment. However, impact assessments provide a detailed basis upon which to quantify the impacts of IAS and include aspects that could be considered for inclusion within full risk assessments. The risk assessment methods based on the protocol devised by EPPO DSS, namely GB NNRA and ENSARS, provide a basis on which to begin developing a list of ‘IAS of EU concern’. However, the breadth of species considered relevant is influenced by the original purposes of both protocols. Harmonia+ is a new and promising risk assessment method. It will be essential to consider the relevance of this protocol as one of the key players going forward. A critical issue exists in the simplification of extrapolating national or regional assessments to the total area of the EU. The EU is rich in biodiversity and is a highly heterogeneous and large territory and so risk assessments of IAS may differ substantially when different regions are considered. Consideration of European biogeographic regions as contex for existing national risk assessments protocols would be appropriate. It is essential to ensure that risk assessments undertaken for restricted regions within Europe (such as the GB NNRA, ENSARS and Harmonia+) have relevance to the EU as outlined above. Review of the applicability of such assessments for EU relevance is unlikely to be trivial for many IAS. Re-assessment of risks identified through national risk assessment protocols at the EU level (with consideration of biogeographic regions) through scientific experts should be prioritised. Further development of the list of proposed “IAS of EU concern” is necessary and should involve scientific experts based on the framework provided by the new EU Regulation. It will be essential to develop a process for consolidating the draft list of proposed “IAS of EU concern” through involvement of scientific experts. The list of proposed “IAS of EU concern” will need to be reviewed on a regular basis to ensure it remains current as the number of new arrivals escalates. Equally the knowledge underpinning our understanding of invasions and environmental change will improve and additional relevant concepts will emerge. Therefore, periodically it will be necessary not only to review the list of proposed “IAS of EU concern” but also the framework of minimum standards upon which it is based as, for example, understanding increases and evidence suggests the need to modify minimum standards or indeed include additional minimum standards. Consideration of the establishment of a formal procedure for evaluating the list of proposed “IAS of EU concern” after 2016 should be prioritised. It will be essential to provide support for cooperation between scientific experts (responsible for the risk assessments) and the Member State and stakeholder experts (responsible for the risk management and communication). Indeed before the final list of “IAS of EU concern” is determined risk management factors should be taken into account, such as how widespread the species is within the EU, what benefits are associated with the species and the cost-benefit of adding the species to the list of “IAS of EU concern"

The microbiome of the Maculinea-Myrmica host-parasite interaction

Maculinea (=Phengaris) are endangered butterflies that are characterized by a very complex biological cycle. Maculinea larvae behave as obligate parasites whose survival is strictly dependent on both particular food plants and species-specific Myrmica ants. In this interaction, Maculinea caterpillars induce Myrmica workers to retrieve and rear them in the nest by chemical and acoustic deception. Social insect symbiotic microorganisms play a key role in intraspecific and interspecific communication; therefore, it is possible that the Maculinea caterpillar microbiome might be involved in the chemical cross-talk by producing deceptive semiochemicals for host ants. To address this point, the microbiota of Maculinea alcon at different larval stages (phytophagous early larvae, intermediate larvae, carnivorous late larvae) was analyzed by using 16S rRNA-guided metabarcoding approach and compared to that of the host ant Myrmica scabrinodis. Structural and deduced functional profiles of the microbial communities were recorded, which were used to identify specific groups of microorganisms that may be involved in the chemical cross-talk. One of the most notable features was the presence in all larval stages and in the ants of two bacteria, Serratia marcescens and S. entomophila, which are involved in the chemical cross-talk between the microbes and their hosts