Habitat shapes diversity of gut microbiomes in a wild population of blue tits Cyanistes caeruleus

Abstract

Microbiome constitutes an important axis of individual variation that, together with genes and the environment, influences an individual's physiology and fitness. Microbiomes are dependent not only on an individual's body condition but also on external factors, such as diet or stress levels, and as such can be involved into feedbacks between the external ecological factors and internal physiology. In our study, we used a wild population of blue tits Cyanistes caeruleus to investigate the impact of external habitat composition on the microbiome of adult birds. We hypothesized that -through differences in plant composition, potentially affecting diet complexity -habitat type may impact the diversity and structure of the gut microbiome. Blue tits breeding in dense deciduous forests tended to have more diverse microbiomes and be significantly different in terms of microbiome composition from birds breeding in open, sparsely forested hay meadows. Distinct study plots also tended to differ in a number of parameters describing microbiome diversity. We observed no microbiome differentiation according to individual characteristics such as sex or age. The study emphasizes that external environment is one of the important modulators of microbiome diversity and calls for more such studies in wild animal populations.

Individual variation in the avian gut microbiota: The influence of host state and environmental heterogeneity

“…Exposure to different environmental pools of microbes are probably important, such as those in the air, soil or diet (Grond et al, 2017; Kartzinel et al, 2019; Liddicoat et al, 2020; Ren et al, 2017). The link with diet is especially likely to explain why gut microbiota can vary with habitat (Drobniak et al, 2021; Goossens et al, 2022; Teyssier, Rouffaer, et al, 2018). Vegetation and diet can also vary dramatically within habitats, for example with respect to edge effects (Chen et al, 1992; Wilkin et al, 2007), although it is unknown whether individual microbial communities are affected by these fine‐scale processes.…”

No evidence for associations between brood size, gut microbiome diversity and survival in great tit (Parus major) nestlings

“…Secondly, breeding habitat may lead to differences in gut microbiome diversity [ 120 ]: adult birds living in deciduous forests have shown to harbor different gut microbiome diversity than their counterparts living in open forested hay meadows. Here, we used a cross-fostering design to study if the rearing environment contributed to the variation in gut microbiome diversity: Our study indicated that the nest of rearing seemed to explain more of the gut microbiome variation than the nest of origin (although not significant), which follows some previous results [ 43 , 44 , 52 ].…”

No evidence for associations between brood size, gut microbiome diversity and survival in great tit (Parus major) nestlings

“…Secondly, breeding habitat may lead to differences in gut microbiome diversity [120]: adult birds living in deciduous forests have shown to harbor different gut microbiome diversity than their counterparts living in open forested hay meadows. Here, we used a cross-fostering design to study if the rearing environment contributed to the variation in gut microbiome diversity: Our study indicated that the nest of rearing seemed to explain more of the gut microbiome variation than the nest of origin (although not significant), which follows some previous results [43–44, 52].…”

“…Secondly, breeding habitat may lead to differences in gut microbiome diversity [120]: adult birds living in deciduous forests have shown to harbor different gut microbiome diversity than their counterparts living in open forested hay meadows.…”