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Aebi, Alexandre

Nom
Aebi, Alexandre
Affiliation principale
Site web
Fonction
MER
Email
alexandre.aebi@unine.ch
Identifiants
https://libra.unine.ch/handle/123456789/769
_
0000-0003-2309-1497

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  • Publication
    Accès libre
    Gene transfers into the environment
    (Neuchâtel Commission fédérale d’éthique dans le domaine non-humain. CENH., 2015-1-14)
    Aebi, Alexandre 
    ;
    Schoenenberger, Nicola
    Global trade and climate change contribute to erase the bio-geographical boundaries separating the ecological niches of numerous species, favouring the emergence or re-emergence of crop pest or disease vector species. This report, commissioned by the Swiss Federal Ethics Committee on Non-Human Biotechnology (ECNH) will describe technologies implying the transfer of genetic material in the environment such as biological control, CRISPR-Cas9 and Wolbachia based technologies. It purposely focuses on technologies that are currently not used in Switzerland but that could be used in the future. The focus is set on potential future technologies. Every technology described is used somewhere in the world, enabling us to discuss biosafety concerns and provide an analysis of the regulation procedures mobilized to evaluate potential environmental risks. A classical biological control case study focusing on risks associated with hybridization between introduced biological control agents and native species showed that the laws regulating releases of environment in the environment is suitable to ensure biosafety but that the environmental risk assessment procedure is incomplete. This case study revealed the need for an harmonized European environmental risk assessment and the need to integrate socio-economic aspects in environmental risk assessment procedures. An analysis of a Wolbachia-based control strategy to control disease vectors showed that the Swiss laws regulating releases of organisms in the environment seems perfectly suitable to ensure biosafety. The environmental risk assessment scheme developed by Australian researchers seems to be adequate to evaluate the risks even if the technology is probably to new for evaluating its long-term appropriateness. The chapters on the CRISPR/Cas9 technology that could be used to control disease vectors such as mosquitoes, herbicide resistant agricultural weeds or invasive alien plants highlighted the disruptive character of the technology, the need for more stringent biosafety measures in gene drive experiments compared to other genetic manipulations and potential gaps between law texts in force in certain countries and this rapidly evolving new technology. To overcome this problem, we encourage regulators to consider a product based regulation rather than a technology-based regulation. To summarize, this works highlights the need to consider every case as a unique case necessitating a precise and thorough evaluation or expertise. We strongly encourage regulators to advocate for case-by-case environmental risk assessment.
  • Publication
    Accès libre
    Plant diversity in a nutshell: testing for small-scale effects on trap nesting wild bees and wasps
    (2014-3-31)
    Fabian, Yvonne
    ;
    Sandau, Nadine
    ;
    Bruggisser, Odile T
    ;
    Aebi, Alexandre 
    ;
    Kehrli, Patrik
    ;
    Rohr RP, Rudolf
    ;
    Naisbit, Russel E
    ;
    Bersier, Louis-Felix
    Declining plant species richness in agro-ecosystems and thus reduced habitat quality can have cascading effects on ecosystem functioning, leading to reduced pollination and biological control. Here we test if plant diversity can affect arthropod diversity and abundance on a very small scale, manipulating plant species richness (2, 6, 12 and 20 sown species) in small adjacent subplots (63 9 m) in 10 wildflower strips in an agricultural landscape. We simultaneously analyzed the effect of plant species richness, vegetation structure, and plant composition on the species richness and abundance of cavity-nesting wild bees, wasps, their prey and natural enemies, and on the structure of their food webs. By separating the trap-nesting species into functional groups according to their prey, we aimed to understand the underlying patterns for the effects of plant diversity. Increasing plant species richness had a significant effect only on spider-predating wasps, the group of wasps trophically most distant from plants. In contrast, bees and food-web structure were unaffected by plant diversity. Spider-predating wasp abundance negatively correlated with the abundance of spiders, suggesting top-down control. Interestingly, the abundance of spiders was the only variable that was strongly affected by plant composition. The hypothesis that the effect of plant diversity decreases with increasing trophic level is not supported by our study, and the mobility of species appears to play a greater role at this small spatial scale.
  • Publication
    Accès libre
    Arthropod symbioses: a neglected parameter in pest- and disease-control programmes
    Zindel, Renate
    ;
    Gottlieb, Yuval
    ;
    Aebi, Alexandre 
    1. Arthropods are important players in biological control as pests, control agents and transmitters of invertebrate diseases. Arthropods are frequently infected with one or several micro-organisms, serving as micro-ecosystems in which multiple interactions can take place. These micro-organisms include disease agents and symbiotic micro-organisms. The latter are usually vertically transmitted and can have a broad spectrum of effects on their hosts, ranging from reproductive manipulations to protection against natural enemies. These interactions may directly or indirectly alter the biology of many arthropods in agriculturally, medically and ecologically relevant ecosystems.
    2. Symbiotic micro-organism-induced reproductive manipulations such as cytoplasmic incompatibility and parthenogenesis induction can substantially affect the rearing of biological control agents. Many insects, and recently also mites and nematodes, have been found to be infected, displaying a wide range of effects. We discuss examples of arthropod-micro-organism interactions and effects, which could have consequences for the practical application of arthropods in biological control.
    3. Symbiotic micro-organisms can also be involved in host protection against natural enemies such as parasitoids, pathogenic bacteria, fungi and viruses.
    4. Symbiotic bacteria can influence the vectorial capacity of disease-vectoring arthropods and may be very helpful in decreasing the transmission of disease agents.
    5. Synthesis and applications. The effect of micro-organisms on the outcome of biological control programmes is usually not considered in risk assessments and failure analyses. This review emphasizes the importance of endosymbiotic micro-organisms in comprehensive biological control programmes and provides recommendations on how to recognize, avoid or benefit from these influential tenants.