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Data from: Life history stage-dependent effects of food supplementation on gut microbiome diversity in Sialia sialis (Eastern Bluebird)

Baiz, Marcella1; Cornell, Allison2

Published Apr 09, 2026 on Dryad. https://doi.org/10.5061/dryad.sqv9s4ngv

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Apr 09, 2026 version files 1.22 MB

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Abstract

Diet can be an important health factor that links fitness to an individual’s ecology. The gut microbiome responds to diet changes and plays an important role in host physiology. Dietary interventions are known to impact gut microbiome composition, but long-term effects and to what extent these impacts vary among individuals at different life history stages is unclear. To address this question, we performed a supplemental feeding experiment by providing live mealworms (Tenebrio molitor) to Sialia sialis (Eastern Bluebirds) during the chick-rearing period. We produced 16S metabarcoding data to quantify gut microbiome diversity from fecal samples of adults and nestlings collected during our experimental period, and again one year later when individuals returned to breed at the study site. Food supplementation was associated with shifts in gut microbiome composition for adults, but not early (8-day-old) or late stage (15-day-old) nestlings. In particular, one bacterium in the genus Staphylococcus was more abundant in food-supplemented adults. Nestling gut microbiomes were similar among nest-mates, and differed between the sexes during early development, but sex-differences disappeared before fledging (nest departure). Microbiome richness was higher in female nestlings, but not related to chick maturity. We did not observe any effects of the previous year’s diet treatment among returning breeders. Humans commonly provide mealworms for S. sialis in order to attract them to their property and to help them achieve nutritional requirements. Our results suggest this practice has limited, short-term effects on gut microbiome diversity that differ among individuals of different life history stages.