Bowel Movement: Integrating Host Mobility and Microbial Transmission Across Host Taxa

Abstract

The gut microbiota of animals displays a high degree of plasticity with respect to environmental or dietary adaptations and is shaped by factors like social interactions, diet diversity or the local environment. But the contribution of these drivers varies across host taxa and our ability to explain microbiome variability within wild populations remains limited. Terrestrial animals have divergent mobility ranges and can either crawl, walk or fly, from a couple of centimeters toward thousands of kilometers. Animal movement has been little regarded in host microbiota frameworks, though it can directly influence major drivers of the host microbiota: (1) Aggregation movement can enhance social transmissions, (2) foraging movement can extend range of diet diversity, and (3) dispersal movement determines the local environment of a host. Here, I would like to outline how movement behaviors of different host taxa matter for microbial acquisition across mammals, birds as well as insects. Host movement can have contrasting effects and either reduce or enlarge spatial scale. Increased dispersal movement could dissolve local effects of sampling location, while aggregation could enhance inter-host transmissions and uniformity among social groups. Host movement can also extend the boundaries of microbial dispersal limitations and connect habitat patches across plant-pollinator networks, while the microbiota of wild populations could converge toward a uniform pattern when mobility is interrupted in captivity or laboratory settings. Hence, the implementation of host movement would be a valuable addition to the metacommunity concept, to comprehend microbial dispersal within and across trophic levels.

Bumble bee microbiota shows temporal succession and increase of lactic acid bacteria when exposed to outdoor environments

“…Second, our initial setup excluded other pollinators and does not allow floral visitation and introduction of microbes from wild pollinators (but only wind-dispersed microbes). Including other insects within a modified setup could provide additional insights about the importance of cross-species transfer of microbes, since vectoring insects can move microbes along the plant-pollinator network and share them with other pollinators ( Keller et al., 2021 ; Zemenick et al., 2021 ; Weinhold, 2022 ). As the third reason, several bumble bees manage to escape through tiny holes that have been bitten into the nets and could be observed returning from foraging flights outside of the cages.…”

Transmission mode and dispersal traits correlate with host specificity in mammalian gut microbes

“…It would be also interesting to investigate the hypothesis that microbial host‐specificity correlates with mammalian traits like sociality. For example, it could be hypothesized that, in social mammals, increased contacts between individuals of the same host species will increase the transmission of gut microbes within host species rather than between host species, which could result in increased host specificity over evolutionary time, compared to nonsocial species (Raulo et al, 2021; Weinhold, 2022).…”

Bumble bee microbiota shows temporal succession and increase of lactic acid bacteria when exposed to outdoor environments

“…Bumble bees are even well capable of dispersing microbes among flowers themselves, as demonstrated with B. impatiens (Russell et al, 2019). Here, flowers should not only be seen as a source of food provision, but as well as dispersal hubs for environmental microbes, so that vectoring insects move microbes along the plant-pollinator network (McFrederick et al, 2017; Keller et al, 2021; Zemenick et al, 2021; Weinhold, 2022).…”