Sampling scheme and protocols
Elements of the trapping procedures followed here have already been partly described in Dalecky et al. (2015), Diagne et al. (2021), and Granjon et al. (2021). The live traps used were of two types: locally made wire-mesh live traps (8.5 × 8.5 × 26.5 cm) and Sherman [H.B. Sherman Traps, Inc., Tallahassee, Florida, USA] folding box traps (8 × 9 × 23 cm). Traps were set inside housing or working units (e.g. dwelling houses, storehouses, shops, workshops) which potentially included inner yards and associated parts (e.g. exterior staircases, verandas). In each of these buildings, traps were set between one and three consecutive nights in different “rooms”. Most of the time, a trap of each type was placed in each room, on the floor, on furniture, or even high up (wall tops, frame…). When the traps were initially set up, each room sampled was georeferenced (geographic coordinates GPS-recorded with an accuracy of +/- 5m). The rooms were classified as belonging to eight “room types”, namely bedrooms, granaries, food shops, kitchens, non-food stores, outdoors, stock rooms and workshops. In the rooms, the presence or absence of food, and the nature (materials) of the floor, walls and ceiling (see modalities in Fig. 1 legend) was noted. This information represents markers of the type of habitat (traditional vs. modern) in which the small mammals studied live in contact with their human hosts. Traps were checked and then baited once a day with peanut butter spread on a slice of fresh onion.
Captured rodents were morphologically identified (following keys provided in Granjon and Duplantier 2009), euthanized by cervical dislocation as recommended by Mills et al. (1995), then weighed to the nearest 0.5g, sexed and dissected. When necessary, molecular data were generated to allow unambiguous species identification of rodents (following procedures described by Lecompte et al., 2005; Dobigny et al., 2011).