A process-based model simulating the life-cycle of Culex pipiens s.s./Cx. torrentium (Diptera: Culicidae) in Germany

Mosquitoes are well known for their ability to transmit pathogens, including various arthropod-borne viruses (arboviruses) of veterinary and medical interest. In Europe, the increasing public health relevance of mosquito-borne pathogens highlights the need to understand how environmental drivers shape mosquito population dynamics relevant to transmission risk. Culex pipiens sensu stricto (s.s.) and Culex torrentium (collectively referred to here as Cx. pipiens s.s./Cx. torrentium) are the primary vectors of Usutu virus and West Nile virus in Europe and are commonly found in and around human settlements. The prediction of their spatial-temporal abundance supports early assessment of arbovirus transmission risk and the planning of effective intervention methods, such as vector control.

A process-based model was developed to simulate the spatial-temporal occurrence of Cx. pipiens s.s./Cx. torrentium in Germany, with a particular focus on depicting realistic overwintering behaviour, including, diapause induced through photoperiod and temperature in the larval stage. The model output is driven by local temperature and rainfall data provided by the European re-analysis and observations for monitoring data set and evaluated with field data from 106 sampling sites in Germany.

A significant association between relative simulated and observed mosquito abundance was found for 75% of the sampling sites, using site-specific beta regression models. An overall beta mixed-effects model across all sites was also significant (estimate = 2.17, standard error = 0.062, Z-value = 35.03, p-value < 0.0001, marginal R² = 0.4).

This model offers a robust framework for the depiction of the mosquito population dynamics of Cx. pipiens s.s./Cx. torrentium under current and future climate scenarios, thereby supporting vector surveillance and control strategies across Europe.