Interplay between historical and current features of the cityscape in shaping the genetic structure of the house mouse (Mus musculus domesticus) in Dakar (Senegal, West Africa)

Abstract

24Population genetic approaches are often used to investigate dispersal patterns of species living in highly 25 urbanized environment in order to improve management strategies for biodiversity conservation or pest 26 control. However, in such environment, population genetic structure may reflect both current features of 27 the cityscape and urbanization history. This can be especially relevant when focusing on non-native 28 invasive commensal rodents that have been introduced in numerous primary colonial European 29 settlements. Accounting for spatial and temporal cityscape heterogeneity to determine how past and 30 recent demographic events may interplay to shape current population genetic structure of synanthropic 31 rodents may provide useful insights to manage their populations. In this study, we addressed these issues 32 by focusing on the house mouse, Mus musculus domesticus, in Dakar, Senegal, where the species may 33 have been introduced as soon as Europeans settled in the middle of the nineteenth century. We examined 34 genetic variation at one mitochondrial locus and 15 nuclear microsatellite markers from individuals 35 sampled in 14 sampling sites representing different stages of urbanization history and different socio-36 economic environments in Dakar. We used various approaches, including model-based genetic clustering 37 and model-free smoothing of pairwise genetic estimates. We further linked observed spatial genetic 38 patterns to historical and current features of Dakar cityscape using random forest and Bayesian 39 conditional autoregressive models. Results are consistent with an introduction of the house mouse at 40 colonial time and current genetic structure reflects the interplay between the historical dynamics of 41 urbanization and the variation of contemporary urban habitats, including socio-economic features, that 42 translate in habitat quality for the house mouse. Our results highlight the potential importance of 43 accounting for past demographic events to understand spatial genetic patterns of non-native invasive 44 commensal rodents in highly urbanized environment.45 46

Native and Invasive Small Mammals in Urban Habitats along the Commercial Axis Connecting Benin and Niger, West Africa

“…Rats and mice were first introduced in West Africa in coastal cities, probably from the pre-colonial period to the present day, and they disseminated within lands, following human movements and goods trade [23,24,[38][39][40]. These invasive rodents expanded rapidly inland over the last decades, with their dispersal being tightly associated with fluvial and road networks, transport improvement, as well as growing urbanization [22][23][24]38,[40][41][42][43][44][45]. As such, history was important in shaping current distributions of invasive rodent species in West Africa.…”

Maritime international trade and bioinvasions: A three‐year long survey of small mammals in Autonomous Port of Cotonou, Benin

“…In any case, our findings represent a novel illustration of species‐specific segregations that have already been observed elsewhere in African commensal habitats facing with biological invasions of exotic rodents. For instance, (i) M. musculus and R. rattus have almost completely replaced native species in many cities and villages of Senegal (Dalecky et al., 2015; Stragier et al., 2019); (ii) R. norvegicus tended to displace R. rattus as early as in the 1950s in Douala, Cameroon (Voelckel & Varieras, 1960); and (iii) the usually highly prolific native Mastomys natalensis was locally replaced by invasive black rats and/or house mice in Niamey, Niger (Garba et al., 2014). An alternative, non‐exclusive explanation could rely on local predator–prey interactions, which may also drive contrasted spatial distributions of the rodents.…”

Toxoplasma gondii in house mice Mus musculus domesticus from Dakar, Senegal: clues for oral rather than vertical mode of infection

“…Two traps (one wire mesh trap and one Sherman trap) were set per room or courtyard in buildings corresponding to dwelling houses, boutiques, workshops, offices or warehouses, and whose locations were precisely recorded with a GPS device. This survey led to the sampling of 481 mice, which were genotyped using a set of 15 microsatellite markers (Stragier et al, 2019) and whose the infectious status was determined using a real-time PCR specific to T. gondii on brain DNA extracts (Galal et al, 2018b).…”