A More Standardized Method for Imaging and Measuring Drosophila Thorax Length Using ImageJ

Thorax
measurements are important metrics of Drosophila
fitness and are often correlated with key life history traits such as lifespan
and fecundity. Therefore, thorax length is a widely used measure in studies of
genetic variation and plasticity in response to environmental alterations.
However, the lack of fixed landmarks means that thorax measurements can sometimes
be inconsistent and highly variable. Here we outline a dorsal bristle-guided
method of thorax measurements, which we could use to draw a reliable and
repeatable line from the thorax scutellum to the anterior thorax edge. We analyzed
and compared this bristle-guided marker method to a non-landmark based thorax
measurement, in a set of measures of female and male D. melanogaster. We found that the bristle-guided method exhibited
significantly less variation between technical replicates than did the
non-landmark based measure.