Intraguild predation between the invasive ladybird Harmonia axyridis and non-target European coccinellid species

The coccinellid Harmonia axyridis (Pallas) has been used for augmentative and classical biological control in many environments. More recently it has invaded large parts of Europe and negative effects for native populations of aphidophagous coccinellids are beginning to emerge. Here we investigate intraguild predation (IGP) between H. axyridis and eleven native non-target European coccinellids, including less common species which have not been studied so far within this context of non-target effects. When first-instars of H. axyridis were paired with the native species, only Anatis ocellata (Linnaeus) and Calvia quatuordecimguttata (L.) were significantly superior to the former whereas H. axyridis was superior in three cases, i.e. against Aphidecta obliterata (L.), Coccinella septempunctata L. and Hippodamia variegata (Goeze). Non-significant results were obtained for all other pairings. Similar tests with the fourth larval instar revealed stronger IGP rates and H. axyridis was found to be superior in the interactions with Adalia bipunctata (L.), Adalia decempunctata (L.), A. obliterata, Calvia decemguttata (L.), C. quatuordecimguttata, C. septempunctata, H. variegata, Oenopia conglobata (L.) and Propylea quatuordecimpunctata (L.) whereas non-significant results were obtained for interactions with two other native species. Another experiment revealed that H. axyridis was able to prey more successfully upon egg of most native coccinellid species than vice versa. However, C. quatuordecimguttata eggs seem to be more protected against predation than those of the other species. Survival of first-instar H. axyridis was higher on conspecific eggs compared to eggs of any other species tested. Our results suggest that H. axyridis may become a threat to a wide range of native aphidophagous coccinellids sharing similar ecological niches except species showing high potential for chemical or physical protectio

Socio‐economic impact classification of alien taxa (SEICAT)

1 Many alien taxa are known to cause socio‐economic impacts by affecting the different constituents of human well‐being (security; material and non‐material assets; health; social, spiritual and cultural relations; freedom of choice and action). Attempts to quantify socio‐economic impacts in monetary terms are unlikely to provide a useful basis for evaluating and comparing impacts of alien taxa because they are notoriously difficult to measure and important aspects of human well‐being are ignored. 2 Here, we propose a novel standardised method for classifying alien taxa in terms of the magnitude of their impacts on human well‐being, based on the capability approach from welfare economics. The core characteristic of this approach is that it uses changes in peoples' activities as a common metric for evaluating impacts on well‐being. 2 Impacts are assigned to one of five levels, from Minimal Concern to Massive, according to semi‐quantitative scenarios that describe the severity of the impacts. Taxa are then classified according to the highest level of deleterious impact that they have been recorded to cause on any constituent of human well‐being. The scheme also includes categories for taxa that are not evaluated, have no alien population, or are data deficient, and a method for assigning uncertainty to all the classifications. To demonstrate the utility of the system, we classified impacts of amphibians globally. These showed a variety of impacts on human well‐being, with the cane toad (Rhinella marina) scoring Major impacts. For most species, however, no studies reporting impacts on human well‐being were found, i.e. these species were data deficient. 2 The classification provides a consistent procedure for translating the broad range of measures and types of impact into ranked levels of socio‐economic impact, assigns alien taxa on the basis of the best available evidence of their documented deleterious impacts, and is applicable across taxa and at a range of spatial scales. The system was designed to align closely with the Environmental Impact Classification for Alien Taxa (EICAT) and the Red List, both of which have been adopted by the International Union of Nature Conservation (IUCN), and could therefore be readily integrated into international practices and policies

Species richness and abundance of native leaf miners are affected by the presence of the invasive horse-chestnut leaf miner

The effect of the alien horse-chestnut leaf miner, Cameraria ohridella, on native fauna was studied by comparing the species richness of native leaf miner communities and the abundance of selected native leaf miner species in the presence and absence of horse-chestnut trees infested by C. ohridella, in various environments in Europe. The species richness of native leaf miner communities in Switzerland was lower at sites where C. ohridella was present than at control sites. In Switzerland, France and Bulgaria, several native leaf miner species were significantly less abundant in the vicinity of infested horse-chestnuts. The native species most affected by the presence of the invasive alien species were those occurring early in the year and sharing their parasitoid complex with C. ohridella. These results suggest apparent competition mediated by shared natural enemies because these are the only link between C. ohridella and native leaf miners using other food resource

Testing a modified version of the EPPO decision-support scheme for release of classical biological control agents of plant pests using Ganaspis cf. brasiliensis and Cleruchoides noackae as case studies

The 6/04 standard of the European and Mediterranean Plant Protection Organisation (EPPO) on the safe use of biological control is a decision-support scheme (DSS) for the import and release of biological control agents in Europe. It was recently developed by the Joint EPPO/International Organisation of Biological Control (IOBC) Panel on Biological Control Agents. The DSS can be used to assess the potential environmental impacts of biological control agents. It is valid for different types of biological control: classical and augmentative biological control of invertebrates, pathogens and weeds. However, the DSS is not yet widely implemented in Europe and, during preliminary trials, it was found that its broad range of usages could lead to some confusion or misunderstandings, as well as requiring unnecessary information in some cases. Thus, the scheme was modified to specifically assess classical biological control against plant pests, i.e. the introduction of exotic natural enemies of plant pests for establishment and long-term control. The new version of the scheme was then tested on two parasitoids that are presently being released in Europe, the figitid Ganaspis cf. brasiliensis against the spotted wing drosophila Drosophila suzukii and the mymarid Cleruchoides noackae against the Eucalyptus bronze bug Thaumastocoris peregrinus. Both parasitoids were successfully assessed with the new version of the DSS. No major issues were encountered during the assessments and most questions were answered with low levels of uncertainty. Both assessments concluded that the parasitoids were safe to release in the impact assessment areas, with positive impacts exceeding negative impacts. Suggestions for potential improvements are provided

Erratum to: Non-crop plants used as hosts by Drosophila suzukii in Europe

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Prioritizing the risk of plant pests by clustering methods; self-organising maps, k-means and hierarchical clustering

For greater preparedness, pest risk assessors are required to prioritise long lists of pest species with potential to establish and cause significant impact in an endangered area. Such prioritization is often qualitative, subjective, and sometimes biased, relying mostly on expert and stakeholder consultation. In recent years, cluster based analyses have been used to investigate regional pest species assemblages or pest profiles to indicate the risk of new organism establishment. Such an approach is based on the premise that the cooccurrence of well-known global invasive pest species in a region is not random, and that the pest species profile or assemblage integrates complex functional relationships that are difficult to tease apart. In other words, the assemblage can help identify and prioritise species that pose a threat in a target region. A computational intelligence method called a Kohonen self-organizing map (SOM), a type of artificial neural network, was the first clustering method applied to analyse assemblages of invasive pests. The SOM is a well known dimension reduction and visualization method especially useful for high dimensional data that more conventional clustering methods may not analyse suitably. Like all clustering algorithms, the SOM can give details of clusters that identify regions with similar pest assemblages, possible donor and recipient regions. More important, however SOM connection weights that result from the analysis can be used to rank the strength of association of each species within each regional assemblage. Species with high weights that are not already established in the target region are identified as high risk. However, the SOM analysis is only the first step in a process to assess risk to be used alongside or incorporated within other measures. Here we illustrate the application of SOM analyses in a range of contexts in invasive species risk assessment, and discuss other clustering methods such as k-means, hierarchical clustering and the incorporation of the SOM analysis into criteria based approaches to assess pest risk

Evaluation des méthodes de piégeage des termites au nord du Burkina Faso

En Afrique de l’Ouest, les termites sont communément utilisés comme alimentation protéinique pour la volaille. Cette étude avait pour objectif de tester et d’améliorer une méthode traditionnelle de collecte des termites par piégeage avec un récipient renversé, au Nord du Burkina Faso. Des essais ont été menés avec deux genres de termites (Macrotermes et Odontotermes) afin d’évaluer l’effet des saisons, des substrats, des récipients et de l’exposition au soleil sur leur piégeage. Six substrats ont été utilisés avec trois types de récipients (en terre cuite, en fer et en plastique) pour collecter les termites. Les résultats ont montré que le canari en terre cuite est le meilleur récipient pour la collecte des termites. Les meilleurs substrats pour capturer les Macrotermes, ont été les substrats contenant des tiges de sorgho et, pour les Odontotermes, les substrats contenant la bouse de vache. L’exposition des pièges au soleil a eu un effet négatif significatif sur les Odontotermes, mais pas sur les Macrotermes. Ces résultats peuvent aider les aviculteurs à améliorer le piégeage des termites en utilisant le récipient et les substrats les plus adéquats et en protégeant leur piège du soleil.Mots clés : Termites, aliments pour volaille, Macrotermes, Odontotermes, Burkina Faso.   English Title: Evaluation of termite trapping methods in northern Burkina Faso In West Africa, termites are commonly used as a protein feed for poultry. The objective of this study was to test and improve a traditional method of trapping termites with an overturned container in northern Burkina Faso. Trials have been conducted with two termite genera (Macrotermes and Odontotermes) to assess the effect of seasons, substrates, containers and sun exposure on their trapping. Six substrates were used with three types of containers (terracotta, iron and plastic) to collect termites. The results showed that the terracotta container is the best container for collecting termites. The best substrates for Macrotermes were the substrates containing sorghum stalks and, for Odontotermes, the substrates containing cow dung. Exposure of the traps to the sun had a significant negative effect on Odontotermes, but not on Macrotermes. These results can help poultry farmers improve termite trapping by using the most suitable container and substrates and protecting their trap from the sun.Keywords: Termites, poultry feed, Macrotermes, Odontotermes, Burkina Faso

Strategies for Biological Control of Invasive Insects

The most widely used of the various approaches to biological control of invasive insects is so-called “conventional” biological control, which consists in introducing natural enemies (parasitoids, predators or pathogens) that originate from the same region as the insect. This approach is particularly well-suited to controlling forest insects because they reduce the pest population directly and lastingly all over the invaded territory. In addition to providing a description of the various stages of a biological control programme, the presentation provided answers to questions often brought up about this type of biocontrol, concentrating particularly on forest tree and woody plant pests. Information supplied by two databases was presented: the BIOCAT2010 base that records all introductions of parasitoids and predators for the purpose of controlling the insects. Another base relating to the entomopathogens used against insects. Up to 2010, more than 6 000 introductions of parasitoids and predators were carried out, targeting 588 species of insects, achieving control over 172 of those insects. Approximately 55 % of these introductions targeted woody plant pests. The rate of establishment of the natural enemies and success rates were higher for woody plant pests than for other pests. The presentation compared the success rates under various production systems and for various groups of woody plants for different orders of insect pests and for different categories of natural enemies. Trends over time since the beginning of conventional biological control at the end of the 19th century were also presented, together with the economic benefits, the risks of the strategy and the measures implemented to limit the latter. Finally, the outlook and obstacles relating to future biocontrol practices in Europe were discussed

Genome divergence and reproductive incompatibility among populations of Ganaspis near brasiliensis.

During the last decade, the spotted wing drosophila, Drosophila suzukii, has spread from eastern Asia to the Americas, Europe, and Africa. This fly attacks many species of cultivated and wild fruits with soft, thin skins, where its serrated ovipositor allows it to lay eggs in undamaged fruit. Parasitoids from the native range of D. suzukii may provide sustainable management of this polyphagous pest. Among these parasitoids, host-specificity testing has revealed a lineage of Ganaspis near brasiliensis, referred to in this paper as G1, that appears to be a cryptic species more host-specific to D. suzukii than other parasitoids. Differentiation among cryptic species is critical for introduction and subsequent evaluation of their impact on D. suzukii. Here, we present results on divergence in genomic sequences and architecture and reproductive isolation between lineages of Ganaspis near brasiliensis that appear to be cryptic species. We studied five populations, two from China, two from Japan, and one from Canada, identified as the G1 vs G3 lineages based on differences in cytochrome oxidase l sequences. We assembled and annotated the genomes of these populations and analyzed divergences in sequence and genome architecture between them. We also report results from crosses to test reproductive compatibility between the G3 lineage from China and the G1 lineage from Japan. The combined results on sequence divergence, differences in genome architectures, ortholog divergence, reproductive incompatibility, differences in host ranges and microhabitat preferences, and differences in morphology show that these lineages are different species. Thus, the decision to evaluate the lineages separately and only import and introduce the more host-specific lineage to North America and Europe was appropriate