Specific gut bacterial responses to natural diets of tropical birds

Abstract

The composition of gut bacterial communities is strongly influenced by the host diet in many animal taxa. For birds, the effect of diet on the microbiomes has been documented through diet manipulation studies. However, for wild birds, most studies have drawn on literature-based information to decipher the dietary effects, thereby, overlooking individual variation in dietary intake. Here we examine how naturally consumed diets influence the composition of the crop and cloacal microbiomes of twenty-one tropical bird species, using visual and metabarcoding-based identification of consumed diets and bacterial 16S rRNA microbiome sequencing. We show that diet intakes vary markedly between individuals of the same species and that literature-based dietary guilds grossly underestimate intraspecific diet variability. Furthermore, despite an effect of literature-based dietary guild assignment of host taxa, the composition of natural diets does not align with crop and cloacal microbiome similarity. However, host-taxon specific gut bacterial lineages are positively correlated with specific diet items, indicating that certain microbes associate with different diet components in specific avian hosts. Consequently, microbiome composition is not congruent with the overall consumed diet composition of species, but specific components of a consumed diet lead to host-specific effects on gut bacterial taxa.

Comparative Analysis of the Gut Microbiota of Three Sympatric Terrestrial Wild Bird Species Overwintering in Farmland Habitats

“…Therefore, it is difficult to disentangle the individual effects of environmental and genetic factors on the gut microbiota. Several studies have identified dietary factors influencing the gut microbiota; however, in these studies, there were significant differences in dietary composition among the individuals within the same species ( Bodawatta et al, 2022b ), and broad dietary classifications (e.g., herbivorous, carnivorous, and omnivorous) were more significant than the variations in diet ( Hird et al, 2015 ). In the winter, farmland-dependent birds have to become herbivory, and thus, our study species share the same dietary factors.…”

Gut microbiome disturbances of altricial Blue and Great tit nestlings are countered by continuous microbial inoculations from parental microbiomes

“…Both species are dimorphic and monogamous, with females building the nest, and laying and incubating the eggs, while both parents feed the brood [42, 44, 45]. BTs and GTs differ in body size [42] and therefore prey selection [46, 47], which is expected to affect gut microbiomes [23, 48].…”

“…BTs and GTs differ in body size [42] and therefore prey selection [46,47], which is expected to affect gut microbiomes [23,48].…”

Within‐community variation of interspecific divergence patterns in passerine gut microbiota

“…Such peculiarity may have arisen due to adaptations of avian digestive system to flight, constraining relative size of individual internals (Bodawatta et al, 2021). Specifically, caeca and other parts of the digestive system are typically reduced in passerines, resulting in lesser potential for physiologically significant and stable host–microbiota interactions (Bodawatta et al, 2022; Caviedes‐Vidal et al, 2007). Major differences between GM of mammals and birds are found also in representation of major bacterial phyla.…”