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”

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

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

Spatially and Financially Explicit Population Viability Analysis of Maculinea alcon in The Netherlands

Background The conservation of species structured in metapopulations involves an important dilemma of resource allocation: should investments be directed at restoring/enlarging habitat patches or increasing connectivity. This is still an open question for Maculinea species despite they are among the best studied and emblematic butterfly species, because none of the population dynamics models developed so far included dispersal. Methodology/Principal Findings We developed the first spatially and financially explicit Population Viability Analysis model for Maculinea alcon, using field data from The Netherlands. Implemented using the RAMAS/GIS platform, the model incorporated both local (contest density dependence, environmental and demographic stochasticities), and regional population dynamics (dispersal rates between habitat patches). We selected four habitat patch networks, contrasting in several basic features (number of habitat patches, their quality, connectivity, and occupancy rate) to test how these features are affecting the ability to enhance population viability of four basic management options, designed to incur the same costs: habitat enlargement, habitat quality improvement, creation of new stepping stone habitat patches, and reintroduction of captive-reared butterflies. The PVA model was validated by the close match between its predictions and independent field observations on the patch occupancy pattern. The four patch networks differed in their sensitivity to model parameters, as well as in the ranking of management options. Overall, the best cost-effective option was enlargement of existing habitat patches, followed by either habitat quality improvement or creation of stepping stones depending on the network features. Reintroduction was predicted to generally be inefficient, except in one specific patch network. Conclusions/Significance Our results underline the importance of spatial and regional aspects (dispersal and connectivity) in determining the impact of conservation actions, even for a species previously considered as sedentary. They also illustrate that failure to account for the cost of management scenarios can lead to very different conclusions

Torymus sinensis: biology, host range and hybridization

Torymus sinensis is a parasitoid of the chestnut gall wasp Dryocosmus kuriphilus, introduced as a biological control agent into Japan, USA, and since 2005, into Europe. Although its effectiveness in controlling the pest was confirmed, some important aspects of its biology, including risks to non-target species, are still unknown or at most scarcely investigated. The results of the present study address an important aspect of the life-cycle of T. sinensis: the existence of extended diapause. Behavioural experiments confirm high levels of host specificity by the parasitoid and suggest that interbreeding with native Torymus species is highly unlikely

Native and introduced parasitoids attacking the invasive chestnut gall wasp Dryocosmus kuriphilus

The globally invasive chestnut gall wasp Dryocosmus kuriphilus was recently reported in Italy and threatens European chestnut orchards and native forests. Of Chinese origin, this species has invaded Japan, Korea, the USA, Nepal and Europe and in each region it has been attacked by parasitoids exploiting oak gall wasps. Classical biological control using the parasitoid Torymus sinensis (Hymenoptera: Torymidae) successfully reduced infestation in Japan. Subsequent work in Japan and Korea showed this parasitoid to represent a poorly understood and biologically diverse species complex. Following its success in Japan, T. sinensis was released in Italy in 2005. A growing appreciation of the taxonomic and ecological complexity of the T. sinensis complex in Japan and Korea has stimulated ongoing DNA-based work on relationships and interbreeding of species in this group. Oak cynipid parasitoids provide potential for native augmentative or conservation biological control of D. kuriphilus in Europe. Exploitation of this potential requires improved understanding of the taxonomy of these parasitoids, particularly of morphologically highly conserved lineages such as Eurytoma and Eupelmus in which recognised species may contain many cryptic lineages. There is a growing need for a molecular survey of the communities centered on chestnut and oak gall wasps to: (1) ascertain the identity of T. sinensis lineages released in Italy (2) track the dispersal of T. sinensis in the native community, either in its original form or as hybrids with native species (3) identify possible biological control agents in the native parasitoid community

Can the enemy release hypothesis explain the success of invasive predators and parasitoids?

Understanding the mechanisms that contribute to alien species becoming invasive is seen as essential for limiting effects of such species. The enemy release hypothesis is widely evoked as an explanation for success but further insight is required to understand the role of natural enemies in regulating alien and native species