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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
    The parasitoid complex of D. suzukii and other fruit feeding Drosophila species in Asia
    (2018-6-27)
    Girod, Pierre
    ;
    Borowiec, Nicolas
    ;
    Buffington, Matthew
    ;
    Chen, Guohua
    ;
    Fang, Yuan
    ;
    Kimura, Masahito T
    ;
    Peris-Felipo, Francisco Javier
    ;
    Ris, Nicolas
    ;
    Wu, Hao
    ;
    Xiao, Chun
    ;
    Zhang, Jinping
    ;
    Aebi, Alexandre 
    ;
    Haye, Tim
    ;
    Kenis, Marc
    Drosophila suzukii is an invasive fly of East Asian origin that has become a serious fruit pest worldwide. Classical biological control through the introduction of parasitoids from Asia could help reduce populations of D. suzukii in invaded regions. Little is known about the native parasitoids of the fly in Asia. Therefore, surveys for larval parasitoids of D. suzukii were carried out in China and Japan between 2015 and 2017. Parasitoids of D. suzukii and other fruit-inhabiting drosophilids (D. pulchrella and D. subpulchrella) that are probably attacked by the same parasitoid complex were found in four Chinese provinces and four Japanese prefectures. Larval parasitoids were obtained at most sites where D. suzukii was found, with parasitism varying from 0.0 to 75.6%. At least eight parasitoid species were reared. The most abundant and frequent parasitoids were the Figitidae Ganaspis cf. brasiliensis and Leptopilina japonica, but another Leptopilina species and at least five Braconidae species belonging to the genera Areotetes, Asobara and Tanycarpa were obtained in low numbers. Due to its likely restricted host range, the most promising parasitoid for biological control is Ganaspis cf. brasiliensis. However, its exact specificity and taxonomic status require future research.
  • Publication
    Accès libre
    Potential for exploitative competition, not intraguild predation, between invasive harlequin ladybirds and flowerbugs in urban parks
    (2015-11-25)
    Howe, Andy G
    ;
    Ravn, Hans-Peter
    ;
    Bressen Pipper, Christian
    ;
    Aebi, Alexandre 
    In aphidophagous insect communities invaded by the harlequin ladybird Harmonia axyridis Pallas (Coleoptera: Coccinellidae), intraguild predation (IGP) is widely implicated in the displacement of native predators, however, indirect trophic interactions are rarely assessed. Using molecular gut-content analysis, we investigated the relative frequencies of IGP by H. axyridis on the predatory flowerbug Anthocoris nemoralis Fabricius (Heteroptera: Anthocoridae) and prey overlap for a shared prey, the lime aphid Eucallipterus tiliae L. (Hemiptera: Aphididae), in Tilia × europaea crowns in urban parks. The frequency of IGP by H. axyridis was low: 2.7 % of larvae and 3.4 % of adults tested positive for A. nemoralis DNA. The presence of lime aphid DNA in predators was higher: 56.5 and 47.9 % of H. axyridis larvae and adults, respectively, contained E. tiliae DNA, whereas 60.8 % of adult A. nemoralis tested positive for aphid DNA. Incorporating insect densities revealed that the density of H. axyridis larvae had a strong negative effect on the likelihood of detecting aphid DNA in A. nemoralis. Prey overlap for E. tiliae was widespread in space (2–13 m height in tree crowns) and time (May–October 2011) which suggests that interspecific exploitative competition, mediated by predator life-stage, more so than IGP, is an important indirect trophic interaction between co-occurring H. axyridis and A. nemoralis. Whether exploitative competition equates to displacement of A. nemoralis populations requires further investigation. Our results emphasize the need to incorporate indirect interactions in studies of insect communities following invasion, not least because they potentially affect more species than direct interactions alone.
  • Publication
    Accès libre
    The potential of native parasitoids for the control of Mexican bean beetles: A genetic and ecological approach
    Aebi, Alexandre 
    ;
    Shani, Tal
    ;
    Hansson, Christer
    ;
    Contreras-Garduno, Jorge
    ;
    Mansion, Guilhem
    ;
    Benrey, Betty 
    Bruchid beetles in the genus Zabrotes are important pests of field and stored beans all around the world and cause enormous economical losses in Mexico and Central America. Native parasitoids have been successfully used to suppress infestations by bruchid beetles in Africa, but few studies have assessed their potential to reduce seed damage in the New World and no successful biological control programs have been implemented, mainly due to the poor knowledge on their biology, systematics and ecology in this region. In this study, we used molecular tools to describe a new complex of three parasitoid species of bruchid beetles in the genus Horismenus, and investigated the level of gene flow and presence of ecotypes in this complex. We also examined the specific association between species of Horismenus and two sibling species of Zabrotes beetles, in order to evaluate their potential as biological control agents. Microsatellite data support the previous morphological description of three species, H. butcheri, H. missouriensis and H. depressus, but suggest some gene flow between H. missouriensis and H. depressus. Host-plant is shown to be the most important factor determining the ecological distribution of the two Zabrotes species, whereas altitude explains most of the distribution of the three Horismenus species. These results complement our understanding of this tritrophic system, providing a solid base for a potential biological control program using native parasitoids.
  • Publication
    Accès libre
    Detecting arthropod intraguild predation in the field
    Aebi, Alexandre 
    ;
    Brown, Peter M. J
    ;
    De Clercq, Patrick
    ;
    Hautier, Louis
    ;
    Howe, Andy
    ;
    Ingels, Brecht
    ;
    Ravn, Hans-Peter
    ;
    Sloggett, John J
    ;
    Zindel, Renate
    ;
    Thomas, Alison
    The process of biological control carries a distinct risk that an alien biological control agent (BCA) will become established as an invasive alien species with an associated threat to the local ecosystem biodiversity. It is imperative that a wide-ranging environmental risk assessment (ERA) is performed before the release of any BCA. This should include considering various potential but difficult to observe ecological interactions between the BCA and members of the native community, including disruption of intraguild relationships. Detection of intraguild predation (IGP) events involving predatory arthropods in the field can be done by analyzing their gut contents. Polymerase chain reaction (PCR) is a sensitive and specific tool to identify target prey DNA within a predator’s gut. This paper reviews the efficiency of a DNA based approach for detecting IGP in the field, compared with detection by the use of monoclonal antibodies or gas chromatography. Prey specificity, detection times after prey consumption, capacity for quantification, multiple prey targeting and the time and costs involved in developing and using the different methods are considered.