Keeping the kids at home can limit the persistence of contagious pathogens in social animals

Lucile Marescot; Mathias Franz; Sarah Benhaiem; Heribert Hofer; Marion East; Stephanie Kramer-Schadt

Model description 120 The model description followed the ODD (Overview, Design concepts, Details) protocol for 121 describing individual-and agent-based models (Grimm et al. 2006 , Grimm et al. 2010 ). The The purpose of our model was to study how disease dynamics in group-living species are 130 affected by an 'offspring with restricted between-group contact' (ORC) trait, which occurs 131 when offspring are kept in subunits or 'modules' such as communal dens and burrows, 132 crèches or family groups within their social groups, until they reach the age at which they can 133 start engaging in between-group interactions. We were particularly interested in whether, and 134 to what extent, such age-dependent patterns of between-group interactions consistently The copyright holder for this preprint (which was not peer-reviewed) is the . https://doi.org/10.1101/2020.04.11.036806 doi: bioRxiv preprint then start roaming more widely within the clan territory, and to accompany their mothers on 142 regular long-distance foraging trips outside the clan territory to areas containing large 143 aggregations of migratory herds East 1993, Hofer et al. 2016 social groups, which consisted of a certain number of individuals, which could change over 159 time due to processes such as mortality and dispersal. 160 Processing and scheduling 161 The model included two main processes: host population dynamics and disease dynamics. At The copyright holder for this preprint (which was not peer-reviewed) is the . https://doi.org/10.1101/2020.04.11.036806 doi: bioRxiv preprint dependent transmission, where the spread of infections depends on the size of the groups, and 166 frequency-dependent transmission, where spread depends on contact frequency and not group 167 size. Abbreviated model parameters (in italics below) are defined in Table 1, where their 168 simulation values are also provided. 169 In the first process (pathogen transmission), the force of infection was influenced by i) the 170 age at first between-group contact, Age-contact, ii) the number (for density-dependent The second process (death) included two forms of mortality: the host intrinsic mortality (1-, 188 with  being the weekly survival probability) and the host mortality induced by the pathogen 189 . CC-BY-NC-ND 4.0 International license author/funder. It is made available under a The copyright holder for this preprint (which was not peer-reviewed) is the . https://doi.org/10.1101/2020.04.11.036806 doi: bioRxiv preprint (virulence ). Individuals who survived over the maximum infection length (IL) gained 190 immunity for the rest of their lives. 191 The third process (reproduction) was regulated by the carrying capacity of the host K. Births 192 occurred only in groups that were below a local breeding capacity, which was defined by the 193 maximum group size. The probability that an individual at a reproductive age of 2 years and 194 more (Age-repro ≥ 104 weeks) gave birth to one offspring was given by fage. and 195 corresponded to approximately 1 -3 offspring per year. 196 The fourth process (dispersal) described individuals which left their natal group as they 197 became reproductively mature. 198 In the last process (ageing), we updated the individual's state variable age as well as the time-199 span-infected counter. The initialization of the age of individuals was determined by a random exponential 202 distribution with a mean set at the age at first reproduction (Age-repro = 104 weeks, T