Language: English with trilingual abstract in English, French, and German
Mosquito-borne diseases such as chikungunya, dengue, Usutu or West Nile, have come back to the forefront in both human and animal health. To prevent outbreaks, it is necessary to acquire a solid knowledge of the mosquito fauna in the considered area. Therefore, and since the mosquito fauna of Luxembourg was only partially known, the authors suggested the construction of the first comprehensive mosquito diversity and distribution database for the Grand Duchy as a base for an atlas.
This atlas of the mosquitoes of Luxembourg assembles a taxonomic list and species distribution maps. To achieve this, the authors collected and synthesised existing mosquito occurrence data, and implemented field surveys to acquire original field data. The latter were based on immature sampling and adult catches performed throughout three years (2019-2021) at sites selected in agriculture, nature or urban land cover categories within each of the 137 5 × 5 km grid squares that cover the territory of the Grand Duchy. Specimens were identified by morphology, but in the case of known cryptic species DNA-based methods were applied in addition.
As a result, the authors assembled two sets of data; firstly, 642 mosquito taxa occurrences from published or unpublished sources from the period 1997 to 2018, and secondly, 22 citizen data and 735 original mosquito occurrences obtained from 560 sites distributed across the Grand Duchy and collected over the period 2019-2021. All data are stored in a unique database that allows the production of updated mosquito distribution maps for the 28 species (31 taxa) reported to occur in Luxembourg to date. The detailed search for existing data allowed us to identify four species that do not appear in published literature but are reported by grey literature or unpublished data sets: Aedes communis, Ae. geminus, Ae. vexans, and Culiseta morsitans.
During their field study, the authors collected all species previously reported except Ae. cinereus (i.e. 22 / 23 species). In addition, they recorded five species new for the country: Ae. refki, Anopheles daciae, An. petragnani, Culex modestus, and Uranotaenia unguiculata. The assembled data reveal the taxon Cx. pipiens/torrentium to be the most widespread and frequently encountered, and probably the most abundant taxon in Luxembourg. The other taxa that show a wide-ranging distribution are An. claviger s.s., An. maculipennis s.l., Ae. geniculatus, Cs. annulata, Ae. annulipes/cantans, Cs. morsitans, Cs. longiareolata, An. maculipennis s.s., Cx. territans, and Ae. rusticus. Taxa that have a very limited distribution range are Ae. cinereus/geminus, Ae. sticticus, Ae. vexans, Coquilletidia richiardii, Ae. refki, An. petragnani, Cs. glaphyroptera, Cx. modestus, and Ur. unguiculata.
Compared to earlier data, this field study does not indicate any species extinction or distribution range retraction. On the contrary, the territory has been colonised in recent years by two new species: Ae. japonicus and Cs. longiareolata. Considering their occurrence in neighbouring countries and the availability of suitable environments in Luxembourg, they also list 22 species which may be found in upcoming field surveys. Further possible changes could indeed occur, with the introduction of additional invasive Aedes container-inhabiting species. As for Luxembourg, there is no environmental or climatic reason that the Asian tiger mosquito Ae. albopictus will not establish populations. Climatic changes may favour the establishment and expansion of warm-climate species in Luxembourg (e.g. An. petragnani, Ae. berlandi), while cold-climate species may be disfavoured and might show a retraction of their ranges (e.g. Ae. communis, Cs. glaphyroptera), according to the degree of changes that will occur in the future.
A primary risk assessment performed for the mosquito species reported to occur in Luxembourg, plus the invasive species Ae. albopictus, shows that at least 15 species could be involved in pathogen or parasite transmission. Considering the nuisance aspect, 18 species may have the potential to disturb humans, with five taxa that can be considered as primary nuisance species.