Diet induces parallel changes to the gut microbiota and problem solving performance in a wild bird

Abstract

Studies in lab rodents indicate diet alters host gut microbiome and that the gut 16 microbiome influences behaviour. However, the ecological relevance across species and in wild 17 animals is unclear. First we showed that problem solving performance in wild-caught great tits 18 (Parus major) was weakly associated with natural variation in the gut microbiome. Then we 19experimentally manipulated the gut microbiome by feeding birds one of two different diets -an all 20insect diet or an all seed/nut diet. We presented these individuals with the problem solving task 21 after the dietary manipulation to test whether the gut microbiome alterations influenced foraging 22innovativeness. Microbial communities changed substantially when given the insect, but not the 23 seed diet. Individuals were less likely to problem-solve after being given the insect diet, and 24 performance was positively associated with microbiome diversity. This is the first demonstration of 25 an association between innovative problem solving and the gut microbiome in a wild animal. 26

Flexibility and resilience of Great tit (Parus major) gut microbiomes to changing diets

“…Exploration of host-gut microbiome dynamics of wild hosts is important to better understand the exibility, resilience and long-term associations of symbiotic interactions under dietary changes. By examining the exibility and resilience of wild omnivorous passerine bird gut microbiomes through diet manipulation, our ndings document a rapid and signi cant impact of diet, aligning with other studies on passerine birds [51,52]. We observed a signi cant deviation in microbial community structure from the initial gut microbiomes after diet manipulation, but we found no signi cant differences in gut communities between the three diet groups (Fig.…”

“…This is potentially associated with more homogeneous nutrient availability in the mealworm diet [58] compared to the more heterogeneous nutrient availability from multiple types of seeds (e.g., sun ower seeds [59], millet [60], and wheat [61]). Additionally, the taxonomic diversity of initial gut microbiomes of P. major in this study differed markedly from the other diet manipulation study [52], where Proteobacteria dominated the gut microbiomes, indicating regional differences. However, the observed similarity in the overall community-level response of gut microbiomes for individuals on seed or insect diets in the two studies, suggest that despite the regional differences of P. major gut microbiomes, microbial communities respond in similar ways to similar dietary changes.…”

“…Microbiomes of birds fed with mealworms experienced signi cantly lower individual variation than birds fed with a standard or a seed diet ( Figure S4). The reduced individual variation in insectivores has been demonstrated in wild birds [14] and in another diet manipulation study of P. major [52], suggesting that a strictly insectivorous diet (mealworms) might be associated with a speci c and more narrow set of gut microbes [58] compared to the seed diet. This is potentially associated with more homogeneous nutrient availability in the mealworm diet [58] compared to the more heterogeneous nutrient availability from multiple types of seeds (e.g., sun ower seeds [59], millet [60], and wheat [61]).…”

“…Intra-speci c differences in bird populations from habitats with potentially different food availabilities further support the plastic nature of bird gut microbiomes [28,31,[45][46][47][48][49][50], as does the higher individual variation and gut bacterial diversity of omnivorous birds compared to bird species with more specialized diets (e.g., insectivores) [14]. The gap in pinpointing the impact of diet on gut microbiomes has to some extent been lled by recent diet manipulation studies of Passer domesticus (house sparrows) [51] and Parus major (great tits) [52], in which gut microbiomes respond according to dietary contents. If dietary changes are regular (e.g., seasonality and migration) we would expect gut microbiomes to cyclically change over time depending on temporal changes in food availability [24,53].…”

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

“…In addition, diet has currently been found to interfere with sex impacts regarding microbiota profiles (Bolnick et al, 2014;Bridgewater et al, 2017). There are several evidence supporting that the avian gut microbiota changes with the shift of feeding habits (Grond et al, 2018;Risely et al, 2018;Wang et al, 2018;Wu et al, 2018;Davidson et al, 2020). However, less is known about the interacting effects of sex and diet on avian gut microbiota under natural conditions.…”