Modelling the effects of spatial heterogeneity and temporal variation in extinction probability on mosquito populations

Abstract

Spatial synchrony plays an important role in dictating the dynamics of spatial and stage-structured populations. Here we argue that, unlike the Moran effect where spatial synchrony is driven by exogenous factors, spatial correlation in intrinsic/local-scale processes can affect the level of spatial synchrony among distinct sub-populations, and therefore the persistence of the entire population. To explore this mechanism, we modelled the consequences of spatial heterogeneity in aquatic habitat quality, and that of temporal variation in local extinction probability, on the persistence of stage-structured mosquito populations. As a model system, we used two widely distributed mosquito species, Aedes albopictus and Culex pipiens, both key vectors of a range of infectious diseases. Spatial heterogeneity in aquatic habitat quality led to increased population persistence, and this pattern was more pronounced at intermediate dispersal rates, and in the long-dispersing species (C. pipiens). The highest regional persistence was obtained at high dispersal rates. This is probably because dispersal, in our model, did not carry any additional costs. Population persistence of both species was negatively correlated with increased temporal variation in local extinction probability. These differences were stronger in the short-dispersing species (A. albopictus), especially at intermediate dispersal rates. The dispersal of A. albopictus adults in each time step was limited to the nearest habitat patches, weakening the positive effect of spatial heterogeneity in aquatic habitat quality on population persistence. In contrast, C. pipiens adults could disperse into more remote sub-populations, resulting in much higher recolonization rates. Hence, the negative effect of temporal variation in local extinction probability on patch occupancy disappeared at intermediate dispersal rates. We suggest that effectively controlling these two mosquito species requires making few spatially synchronized control efforts (i.e., generating high temporal variation in local extinction probability), rather than many asynchronized local control efforts. Finally, our model can be easily fitted to other organisms characterized by complex life cycles, and it can be also used to examine alternative scenarios, including the effect of spatial configuration of local habitat patches and dispersal kernel shape on population persistence.

Trade-off between local transmission and long-range dispersal drives infectious disease outbreak size in spatially structured populations

“…An alternative in which space is also implicit are the so-called patch-occupancy models. Here, the population is made up of a number of predefined suitable patches that may or may not be occupied by hosts or pathogens [13][14][15][16][17]. There are also models that evaluate the infection dynamics in an explicit spatial setting [5,[18][19][20][21].…”

The potential effects of climate change on the populations of Aedes punctor (Diptera: Culicidae) in Hungary

“…punctor can strongly depend on the climatic alterations, other factors can also play a role in this process. These potential non-climatic elements are as follows: (1) the dispersal rate of the species and (2) spatial heterogeneity and the quality of aquatic habitats (Alcalay et al 2017). The flying dispersal rate of Ae.…”

“…The second criterium of Alcalay et al (2017) is related to the larval and general habitats or, in other words, the realized ecological niche of the species. However, at the first step, because this second criterium assumes niche conservatism that may not necessarily occur, the possibility of a niche shift should be discussed.…”

Ecological predictors of mosquito population and arbovirus transmission synchrony estimates

“…Theoretical work has also examined the climatic and spatial factors that influence synchrony in mosquitoes. A mathematical model representative of Culex nigripalpus Theobald in Florida determined that precipitation patterns can force synchronous population fluctuations (Shaman and Day 2007), while a separate model representative of Culex pipiens Linnaeus and Aedes albopictus Skuse concluded dispersal rescues populations across expansive and spatially heterogeneous landscapes, which has important implications for the design of local and regional mosquito control programs (Alcalay et al 2017). While these studies provide evidence that local and regional factors influence synchrony of mosquito species of public health concern, there are no studies that address the generality of synchrony among communities of mosquitoes and the viruses they transmit to humans and wildlife at scales relevant to public health.…”