Research Article |
Corresponding author: Andjeljko Petrović ( andjeljko@bio.bg.ac.rs ) Academic editor: Jose Fernandez-Triana
© 2017 Andjeljko Petrović, Jelisaveta Čkrkić, Aiman Jamhour, Olivera Petrović-Obradović, Milana Mitrović, Petr Starý, Barbro Nedstam, Željko Tomanović.
This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Citation:
Petrović A, Čkrkić J, Jamhour A, Petrović-Obradović O, Mitrović M, Starý P, Nedstam B, Tomanović Ž (2017) First record of Aphidius ericaphidis (Hymenoptera, Braconidae) in Europe: North American hitchhiker or overlooked Holarctic citizen? Journal of Hymenoptera Research 57: 143-153. https://doi.org/10.3897/jhr.57.12517
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Aphidius ericaphidis, an aphid parasitoid originally described from North America, is recorded in Europe for the first time, based on morphological and molecular analyses. The species is recorded in Serbia, the Netherlands, Sweden and the United Kingdom. It was formerly recorded as Aphidius sp./Ericaphis latifrons/Vaccinium uliginosum from the Alps (France). The possible origin of A. ericaphidis, as well as its likely distribution, is discussed in relation to its host. As it is a specific parasitoid of Ericaphis aphids, especially the invasive aphid Ericaphis scammelli on blueberries, its potential as a biocontrol agent is also discussed.
Alien species, Aphidius ericaphidis , Ericaphis scammelli , blueberries, biological control
Growing of highbush blueberry started with the experiments of
One of the economically most important blueberry pathogens is the blueberry scorch virus (BlScV), which was first observed in Washington, USA, in commercial blueberry fields (
The blueberry scorch virus is transmitted mainly by Ericaphis fimbriata (Richards) in a nonpersistent manner (
The braconid parasitoid complex of E. scammelli (=E. fimbriata) in North America consists of 10 species (Hymenoptera: Aphidiinae), among which the most common are Praon unicum Smith, 1944 and Aphidius ericaphidis Pike & Starý, 2011 (
During the last several years, the Aphidiinae fauna on different fruit species was investigated throughout Europe. Samples of Vaccinium spp. leaves with aphids and mummies were collected. The samples were kept under laboratory conditions until parasitoid emergence. After emergence, parasitoids were immersed in 96% ethanol and preserved for later examination. External morphology of the specimens was studied using a ZEISS Discovery V8 stereomicroscope. Scanning electron micrographs were obtained using a JEOL JSM-6390 scanning electron microscope. All specimens are deposited in the collection of the Institute of Zoology, Faculty of Biology, University of Belgrade and the collection of P. Starý, České Budĕjovice, Czech Republic.
Three A. ericaphidis specimens from Scotland were used for molecular analysis. DNA was extracted from individual adult wasps using the Qiagen DNeasy Blood & Tissue Kit (Qiagen Inc., Valencia, CA) following the manufacturer’s instructions. The barcoding region of the mitochondrial cytochrome oxidase subunit I (COI) gene was amplified using the primers LCO1490 and HCO2198 (
DNA amplification was performed in a final volume of 20 μl containing 1 μl of DNA, 11.8 μl of H2O, 2 μl of High Yield Reaction Buffer A with 1 x Mg, 1.8 μl of MgCl2 (2.25 mM), 1.2 μl of dNTP (0.6 mM), 1 μl of each primer (0.5 μM) and 0.2 μl of KAPATaq DNA polymerase (0,05U/μl) (Kapa Biosystems Inc., USA). PCR was conducted in an Eppendorf Mastercycler® (Hamburg, Germany) using the following thermal profile: initial denaturation at 95°C for 5 min, followed by 35 cycles of 94°C for 60 s, 54°C for 60 s, 72°C for 90 s and a final extension step at 72°C for 7 min. Purification of PCR products and DNA sequencing in both directions was performed by Macrogen Inc. (Seoul, Korea).
Sequences of A. ericaphidis specimens from North America and other Aphidius species were obtained from GenBank and used in phylogenetic analysis. Those Aphidius species were chosen because of their morphological similarity to A. ericaphidis or because they parasitize E. scammelli. An Ephedrus sp. sequence from GenBank (acc. number KR787408) was used as an outgroup taxon. Sampling data for specimens used in this study are given in Table
Parasitoid | Code | Geographic origin | Aphid host | Plant | Accession number |
---|---|---|---|---|---|
Aphidius ericaphidis | IM50 | Scotland | Ericaphis scammelli | Vaccinium corymbosum | KY513289 |
Aphidius ericaphidis | IM51 | Scotland | Ericaphis scammelli | Vaccinium corymbosum | KY513290 |
Aphidius ericaphidis | IM52 | Scotland | Ericaphis scammelli | Vaccinium corymbosum | KY513291 |
Aphidius ericaphidis | Canada/USA | Ericaphis fimbriata | Vaccinium corymbosum | KC211024 | |
Aphidius ericaphidis | Canada/USA | Ericaphis fimbriata | Vaccinium corymbosum | EU574902 | |
Aphidius avenaphis | USA | Sitobion avenae | Triticum aestivum | JN164784 | |
Aphidius matricariae | Canada | KR888554 | |||
Aphidius urticae | UK | JX507436 | |||
Aphidius ervi | Canada/USA | KC211026 | |||
Ephedrus sp. | KR787408 |
Sequences were edited using FinchTV ver 1.4.0 (http://www.geospiza.com). Alignment was conducted using CLUSTAL W integrated in MEGA 5 software (
A phylogenetic tree was constructed using the MEGA 5 software (
Aphids infesting Vaccinium corymbosum in Serbia, Sweden and Scotland were identified as E. scammelli. Rearing parasitoids from E. scammelli resulted in finding the species A. ericaphidis for the first time in Europe. Aphidius ericaphidis is recorded in Serbia, Sweden and the United Kingdom (Scotland). Additional re-examination of collections (P. Starý) led to identification of A. ericaphidis in France and the Netherlands as well, the re-examined specimens from both countries having been previously identified as Aphidius sp. (
As the original differential diagnosis of A. ericaphidis referred to North American congeners (
Fig.
Serbia, Mladenovac, 10 VI 2015, 7 females and 4 males reared from Ericaphis scammelli on Vaccinium corymbosum; 23 VI 2015, 3 males reared from Ericaphis scammelli on Vaccinium corymbosum. United Kingdom, Scotland, 19 VI 2014, 9 females and 5 males reared from Ericaphis scammelli on Vaccinium corymbosum. Sweden, Glemmingebro, Scania, 24 VI 2008, 1 female and 1 male from Ericaphis scammelli on Vaccinium corymbosum; 30 VI 2008, 5 females and 5 males from Ericaphis scammelli on Vaccinium corymbosum, greenhouse. Netherlands, Kootwijk, 8 VI 1965, 1 female from Ericaphis latifrons on Empetrum nigrum. France, Lognan (Hte-Savoie), 12 VIII 1968, 1 female and 1 male from Ericaphis latifrons on Vaccinium uliginosum.
Three barcoding sequences of A. ericaphidis originating from Scotland were compared with two sequences of A. ericaphidis from the USA and were determined to be identical, with no variable sites detected.
Topology of the phylogenetic tree shows clear separation of A. ericaphidis from other Aphidius species used in the analysis (Fig.
Highbush blueberry production has been on the rise in the world, and as a consequence of increased international trade of planting material, plant pathogens and pests are also being spread to new areas. In the last 15 years, two exotic Vaccinium pathogens with North American origin (Monilinia vaccinii-corymbosi and BlScV) were detected in Europe, and it is assumed that both were imported with plant material (
However, our revision of material from earlier collections from France and the Netherlands showed that the parasitoid has been present in Europe at least as long as E. scammelli (if not longer). At the time of the records, blueberry production in Europe wasn’t as extensive as it is today, and the import of plants from North America was limited to a few countries. The record from France suggests that those populations of A. ericaphidis had enough time to spread and establish, especially since the record is from a native high mountain ecosystem (Vaccinium uliginosum/Ericaphis latifrons/Aphidius ericaphidis).
The lack of any genetic differences shows that analysed European and North American populations of A. ericaphidis are very closely related. This can suggest that the analysed specimens were from a recent introduction or that they represent a species with no genetic differentiations based on the COI gene, as has been recorded before for some other Aphidius species (A. uzbekistanicus and A. avenaphis) (
Since molecular and morphological analyses of the target parasitoid populations revealed no significant differences, it might be concluded that A. ericaphidis is a member of the Holarctic forest tundra faunistic complex (
The current known host range of European populations of A. ericaphidis is similar to that of North American populations, with the vast majority of records reported from Ericaphis aphids (
The current distribution of A. ericaphidis and that of its host Ericaphis scammelli in Europe are most likely much broader than those recorded so far, and field surveys should therefore be conducted in all Vaccinium growing areas to monitor the spread of A. ericaphidis in Europe and possible changes of its host range.
This study was supported by the Ministry of Education, Science and Technological Development of the Republic of Serbia (project III43001). The participation of P. Starý was funded by the Institute of Entomology, while that of B. Nedstam (ret.) was funded by the Swedish Board of Agriculture. We thank the Viridaxis company for the loan of A. ericaphidis specimens from Scotland.
Table
Data type: species data