Staff directory
Nathalie Smitz
Biology
Invertebrates
Invertebrates
Publication details
Smitz, N., De Wolf, K., Deblauwe, I., De Witte, J., Schneider, A., Verlé, I., Vanslembrouck, A., Dekoninck, W., Meganck, K., Gombeer, S., Vanderheyden, A., De Meyer, M., Backeljau, T. & Van Bortel, W. 2020. ‘A pipeline for DNA-based identification of exotic and native mosquitoes in Belgium’. AIM-COST. Book of abstracts.
Conference abstract
A critical point in monitoring exotic mosquito species (EMS; Diptera: Culicidae) is the correct identification of specimens. This can be difficult in the case of damaged individuals, immature stages or cryptic taxa. When morphology-based species identification becomes problematic, DNA-based techniques can provide rapid and reliable EMS identifications. In the framework of the MEMO project (Monitoring of Exotic MOsquitoes), which aims at detecting EMS and their introduction pathways in Belgium, a systematic DNA validation of (suspected) EMS is performed, irrespective of the developmental stage (egg, larva, pupa, adult). Besides the validation of EMS identifications, a random 5% of the annually collected mosquito specimens is verified by DNA-based approach (approximately 1,000 specimens/year), as quality control of the morphology-based identifications. Since 2017, twenty-three points of entry (PoE’s) are monitored in Belgium, including used tyre and lucky bamboo import companies, airports and car parking lots along highways. Method- To perform DNA-based species identifications, we first evaluated the available DNA markers for each mosquito species (native and exotic) recorded and encountered in Belgium (N=37). For each DNA marker, we checked the number of reference sequences and their geographical coverage, as well as their ability to provide reliable identifications. Afterwards, an identification pipeline was developed, including multiple markers to obtain an identification at species level (COI,ITS2,ACE2,CQ11). Except for three species complexes (all native), all species were considered reliably identifiable by DNA-based methods. For the three complexes (Nspecies=6), we are currently investigating alternative markers, tested on Belgian specimens. Results- All EMS could be distinguished from the native culicids and identified with high reliability using DNA barcoding. Presently, four EMS were collected once or multiple times at one or multiple PoE’s: Aedes koreicus, Ae. japonicus, Ae. albopictus, and Anopheles pharoensis. Besides EMS identification, 11 and 18 native species/complexes were validated in 2017 and 2018, respectively. In addition, the monitoring project resulted in the detection of three new species for Belgium: Culex modestus, Culiseta longiareolata and Anopheles daciae. Significance- EMS were found to enter Belgium repeatedly through different introduction pathways. The DNA-based approach has proven its usefulness to ensure the quality of the morphological identifications and confirm the presence of EMS, especially in case of damaged specimens or immature stages like eggs. The final contribution to the project will be to develop a DNA reference collection of all mosquito species, which will be useful for future monitoring programs.