Fig. 1

Host-microbiome dynamics and microbial inheritance in our model. A Dark blobs indicate hosts, coloured- and empty-circles indicate microbes and empty-space, respectively. Within the hosts, microbes go through a death and immigration-birth process, with new residents migrating from the pool of colonizing microbes with probability m or replicating within a host with probability \(1-m\). For microbes, each host is an identical habitat. The host population is at a dynamic equilibrium, every timestep there is a probability \(\tau\) that a host death occurs, immediately followed by the birth of a new one. The newborn obtains a sample of its parent microbiome according to a probability distribution. B The probability distribution of the fraction of the parental microbiome inherited vary across host taxa—among others, influenced by development, reproduction and delivery mode. Certain hosts might not transfer microbes (eg. C. elegans [25] or D. melanogaster [26]). Others might provide minimal (eg. humans [11]) or large fractions of their microbes (eg. fragmentation of some sponges, corals, fungi and plants [27, 28]), while others might be centred around a fixed value (eg. seeds of plants [17]). In our model, we control this probability distribution through the parameters \(a_i\) and \(b_i\) in Eq. (4)