Data from: Diurnal moths have larger hearing organs: Evidence from comparative 3D morphometric study on geometrid moths

Tympanal organs, crucial for anti-bat defence in moths and key for
taxonomy, are often overlooked due to their fragility during dissection.
Using micro-CT, we analyzed the tympanal organs of 19 geometrid species,
comparing diurnal and nocturnal species to understand how predators, like
bats and diurnal birds or lizards, influence tympanal morphology and its
allometric relationship with body size. We hypothesized that diurnal
moths, with reduced anti-bat function, would have smaller tympanal organs,
irrespective of body size. Allometry was tested using phylogenetic linear
regression and tympanal volume was compared across diurnal and nocturnal
moths relative to the abdominal volume. We used 3D geometric morphometry,
followed by comparative analysis of the shape and size of ansa, a unique
“mechanical” for geometrids. Contrary to our hypothesis, diurnal moths had
significantly larger tympanal organs, with no allometric relationship with
body size. Activity patterns had no significant effect on ansa shape and
size, but nocturnal species exhibited convergence, suggesting potential
auditory functions. This study shows how daily activity patterns and
predator-prey interactions shape sensory adaptations, with larger tympanal
organs of diurnal species potentially reflecting adaptations to detect
lower “non-bat” frequency. It also highlights non-invasive imaging
techniques for studying delicate anatomical features in museum specimens.