2019 Itasca, MN Data Files

The goal of this study was to determine the role of gut microbiota in shaping how birds respond to nest parasites and investigate whether this relationship varies between host species. Both eastern bluebirds (<i>Sialia sialis</i>) and tree swallows (<i>Tachycineta bicolor</i>) are parasitized by blow flies (<i>Protocalliphora sialia</i>), for which larval flies feed on nestlings’ blood. We experimentally manipulated the gut microbiota of nestling bluebirds and tree swallows by dosing nestlings with an oral antibiotic or sterile water as a control. We then quantified nestling physiology (hemoglobin, glucose, parasite-specific IgY antibody levels), body morphometrics, and survival until fledging, as well as blow fly abundance and size. The sequences for the manuscript have been uploaded to GenBank (BioProject accession number: PRJNA1174810).