Abstract
<jats:p> Zoonotic and other livestock-associated pathogens move readily within animal production systems, yet their dispersal into surrounding environments is poorly characterized. We evaluated whether synanthropic filth flies act as spatially integrating sentinels of livestock-associated pathobiomes. From 30 roadside sites in six Texas counties stratified by livestock production intensity, we collected 3,373 Calliphoridae spp. and 12 <jats:italic>Musca domestica</jats:italic> , together with co-located soil, water, plant, and fecal samples, and characterized 195 metagenomes (122 insect, 73 environmental). Using diversity, differential-abundance, machine-learning, indicator-species, and network analyses, we found three robust patterns. First, fly metagenomes form a microbial compartment compositionally distinct from co-located environmental matrices (PERMANOVA R² = 0.094, F = 19.81, P = 0.001) and carry markedly higher relative abundances of pathogen-associated taxa, so insect sampling is complementary to, not redundant with, environmental sampling. Second, the dominant landscape signal is categorical rather than graded: cattle presence, not a Low–Medium–High density gradient, most strongly correlated with community structure, with the ruminant-associated anaerobe <jats:italic>Peptostreptococcus russellii</jats:italic> as the most reproducible biomarker. Third, intensification produced taxon-level enrichments (notably the feedlot pathogen <jats:italic>Trueperella pyogenes</jats:italic> ) and progressive co-occurrence-network fragmentation, without a monotonic dose-response. A curated 12-pathogen panel failed to classify landscape context, whereas whole-community analysis succeeded. Filth flies thus provide a pragmatic, spatially integrated readout that distinguishes low-impact from livestock-impacted landscapes, offering a defensible tool for One Health pathogen surveillance. </jats:p>