Aedes albopictus and Aedes japonicus - two invasive mosquito species with different temperature niches in Europe

Abstract

Background: Aedes albopictus and Ae. japonicus are two of the most widespread invasive mosquito species that have recently become established in western Europe. Both species are associated with the transmission of a number of serious diseases and are projected to continue their spread in Europe.

Methods: In the present study, we modelled the habitat suitability for both species under current and future climatic conditions by means of an Ensemble forecasting approach. We additionally compared the modelled MAXENT niches of Ae. albopictus and Ae. japonicus regarding temperature and precipitation requirements.

Results: Both species were modelled to find suitable habitat conditions in distinct areas within Europe: Ae. albopictus within the Mediterranean regions in southern Europe, Ae. japonicus within the more temperate regions of central Europe. Only in few regions, suitable habitat conditions were projected to overlap for both species. Whereas Ae. albopictus is projected to be generally promoted by climate change in Europe, the area modelled to be climatically suitable for Ae. japonicus is projected to decrease under climate change. This projection of range reduction under climate change relies on the assumption that Ae. japonicus is not able to adapt to warmer climatic conditions. The modelled MAXENT temperature niches of Ae. japonicus were found to be narrower with an optimum at lower temperatures compared to the niches of Ae. albopictus.

Conclusions: Species distribution models identifying areas with high habitat suitability can help improving monitoring programmes for invasive species currently in place. However, as mosquito species are known to be able to adapt to new environmental conditions within the invasion range quickly, niche evolution of invasive mosquito species should be closely followed upon in future studies.

Keywords: Asian bush mosquito; Asian tiger mosquito; Climate change; Invasive species; Species distribution modelling.

Fig. 1

Observed and modelled European distribution for Aedes albopictus and Ae. japonicus. a Occurrence records for Ae. albopictus (n = 336). b Modelled habitat suitability for Ae. albopictus under current climatic conditions, Ensemble forecasting (AUC = 0.972). c Occurrence records for Ae. japonicus (n = 178). d Modelled habitat suitability for Ae. japonicus under current climatic conditions, Ensemble forecasting (AUC = 0.999)

Fig. 2

Area with modelled habitat suitability (Ensemble forecasting) in Europe for Aedes albopictus and Aedes japonicus and both mosquito species under current climatic conditions. Sensitivity equals specificity threshold was applied to yield binary modelling results

Fig. 3

Modelled habitat suitability (Ensemble forecasting) for Aedes albopictus under current and future climatic conditions

Fig. 4

Modelled habitat suitability (Ensemble forecasting) for Aedes japonicus under current and future climatic conditions

Fig. 5

One-variable-response-curves for Aedes albopictus (solid line) and Aedes japonicus (dotted line) considering the different environmental variables (required: AUC value for the one variable model for both species > 0.75, see Table 2)