Bellymount enables longitudinal, intravital imaging of abdominal organs and the gut microbiota in adult Drosophila

Cell- and tissue-level processes often occur across days or weeks, but few imaging methods can capture such long timescales. Here we describe Bellymount, a simple, non-invasive method for longitudinal imaging of the Drosophila abdomen at sub-cellular resolution. Bellymounted flies remain live and intact, so the same individual can be imaged serially to yield vivid time series of multi-day processes. This feature opens the door to longitudinal studies of Drosophila internal organs in their native context. Exploiting Bellymounts capabilities, we track intestinal stem cell lineages and gut microbial colonization in single flies, revealing spatiotemporal dynamics undetectable by previously available methods.