Effects of Sex and Diet on Gut Microbiota of Farmland-Dependent Wintering Birds

Abstract

Gut microbiota plays an important role for bird biological and ecological properties, and sex and diet may be important intrinsic and extrinsic factors influencing gut microbial communities. However, sex difference of gut microbiota has been rarely investigated in free-living birds, and it remains unclear how sex and diet interactively affect avian gut microbiota composition and diversity, particularly under natural conditions. Here we used non-invasive molecular sexing technique to sex the fecal samples collected from two wintering sites of Great Bustard, which is the most sexually dimorphic among birds, as well as a typical farmland-dependent wintering bird. High-throughput sequencing of 16S was applied to identify the gut microbiota communities for both sexes under two diets (wheat_corn and rice_peanut). The results showed that 9.74% of common microbiota taxa was shared among four groups (sex vs. diet), revealing the conservatism of gut microbiota. Microbiota diversity, composition and abundance varied on different diets for male and female Great Bustards, suggesting that the gut microbiota was interactively influenced by both sex and diet. Under the wheat_corn diet, females had higher abundances of the phylum Verrucomicrobia than males, but lower Bacteroidetes and Firmicutes compared to males; meanwhile, the microbiota diversity and evenness were higher for males than females. In contrast, under the rice_peanut diet, females were more colonized by the phylum Firmicutes than males, but less by the phylum Bacteroidetes; while males had lower microbiota diversity and evenness than females. This study investigated the impacts of sex and diet on microbiota of Great Bustards, and highlights the need of new studies, perhaps with the same methodology, taking into account bird ages, flock size, breeding or health status, which will contribute to the understanding of ecology and conservation of this vulnerable species.

The gut microbiota of wild wintering great bustard (Otis tarda dybowskii): survey data from two consecutive years

“…This result was largely consistent with previous studies, which report that Great Bustards from wintering habitats with differing diet modes (wheat-corn and rice-peanut) have different gut microbial compositions. These findings collectively suggest that diet is potentially a significant microbial composition determinant in Great Bustards ( Liu et al, 2020 ).…”

“…In addition, the uncontrollable variations between individuals are a common challenge for gut microbiome studies in wild birds ( Wang et al, 2019 ; Wang et al, 2020 ). Compared with previous studies of this threatened species ( Liu et al, 2020 ), this study employed a larger sample size to improve the accuracy of the partial results.…”

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

“…Similar microbiome compositions were reported for great tits in several other studies (Davidson et al, 2019(Davidson et al, , 2020, but population differences may paly role to some extent (e.g., Teyssier et al (2018) reported great tit microbiomes dominated by Firmicutes and Actinobacteria, with only small prevalence of Proteobacteria; notably, their analyses were done on fledglings, contrary to our study and other cited studies which used at least 1-year old adults). Blue tit microbiomes do significantly differ from microbiomes of other bird species (e.g., Darwin's finchesdomination of Firmicutes and Actinobacteria (Loo et al, 2019); swan geese -domination of Firmicutes (Wu et al, 2018); white ibises -domination of Firmicutes (Murray et al, 2020); great bastards -domination of Firmicutes and Bacteroidetes (Liu et al, 2020)), which may reflect general differences due to different dietary niches (Waite & Taylor, 2015;Grond et al, 2018).…”

Wild gut microbiomes reveal individuals, species, and location as drivers of variation in two critically endangered tropical birds

“…In the current study we found a higher presence of the bacterial classes Melainabacteria, Mollicutes, Phycisphaerae, and especially, Negativicutes in males than females. Another study on wild birds found an association with Negativcutes and male birds (Liu et al 2020).…”