dynamAedes: a unified modelling framework for invasive Aedes mosquitoes

Abstract

Mosquito species belonging to the genus Aedes have attracted the interest of scientists and public health officers because of their capacity to transmit viruses that affect humans. Some of these species were brought outside their native range by means of trade and tourism and then colonised new regions thanks to a unique combination of eco-physiological traits. Considering mosquito physiological and behavioural traits to understand and predict their population dynamics is thus a crucial step in developing strategies to mitigate the local densities of invasive Aedes populations. Here, we synthesised the life cycle of four invasive Aedes species (Ae. aegypti, Ae. albopictus, Ae. japonicus and Ae. koreicus) in a single multi-scale stochastic modelling framework which we coded in the R package dynamAedes. We designed a stage-based and time-discrete stochastic model driven by temperature, photo-period and inter-specific larval competition that can be applied to three different spatial scales: punctual, local and regional. These spatial scales consider different degrees of spatial complexity and data availability by accounting for both active and passive dispersal of mosquito species as well as for the heterogeneity of the input temperature data. Our overarching aim was to provide a flexible, open-source and user-friendly tool rooted in the most updated knowledge on the species' biology which could be applied to the management of invasive Aedes populations as well as to more theoretical ecological inquiries.

Keywords: Biological invasions; Dispersal; Insects; Invasion ecology; Mosquitoes; Process-based models; Spatial epidemiology; Vector-borne pathogens.

Fig. 1

Graphical representation of dynamAedes model structure, adapted from Da Re et al. [10]: a the life cycle of a generic simulated mosquito species, while in b a representation of active and passive dispersal processes happening within the Adult (A) compartment at local scale. E: egg compartment; Ed: diapause egg compartment (available for all species except Ae. aegypti), J juvenile compartment, A adult compartment, Aad adult active dispersal, Apdd adult passive dispersal, Apd adult probability of getting into a car

Fig. 2

dynamAedes allows to simulate Aedes mosquitoes population dynamics at three different spatial scales. Considering the European continent as example (a), dynamAedes can predict the mosquito population dynamics at regional (b), local (c) and punctual (weather station; d) scale. Passive and active dispersal is enabled only at local spatial scale

Fig. 3

Predicted percentage of established introductions of Ae. aegypti a and Ae. albopictus b in California (USA) for the years 2011–2016 and 2013–2018, respectively. The red dots represent the centroids of the Californian municipalities with established populations in 2021 as reported by the Californian Department of Public Health (CDPH)

Fig. 4

Percentage of successful introduction for Ae. albopictus in France for the years 2015–2020: a Model prediction, b model prediction and, in red dots, the centroids of the French Municipalities with established population of Ae. albopictus reported by the French Health Ministry (SI-LAV)

Fig. 5

Temporal trend reporting simulated (dashed black line) and observed (red line) new-laid eggs of Ae. albopictus in Nice, SE France (2014–2018). The light blue bands represent the winter seasons, whereas the orange bands summer seasons. The simulated data were rescaled for graphical purposes by using the ratio between the maximum observed value, and the maximum median simulated value

Fig. 6

The distributions of simulated population abundances (boxplots) and the relative observed median abundance (red dots) of Ae. koreicus host-seeking females for the years 2016 (a), 2017 (b) and 2018 (c) in Trento, NE Italy