Data from: Scaling of morphological characters across trait type, sex and environment: a meta-analysis of static allometries

Biological diversity is to a large extent a matter of variation in size.
Proportional (isometric) scaling where large and small individuals are
magnified versions of each other is often assumed the most common way
morphological traits scale relative to overall size within species.
However, the many traits showing non-proportional (allometric) scaling
have motivated some of the most discussed hypotheses on scaling
relationships in biology, like the positive allometry hypothesis for
secondary sexual traits and the negative allometry hypothesis for
genitals. I evaluate more than 3200 allometric parameters from the
literature and find that negative allometry, not isometry, is the expected
scaling relationship of morphological traits within species. Slopes of
secondary sexual traits are more often steeper compared to other traits,
but slopes larger than unity is also common for traits not under sexual
selection. The steepness of the allometric slope is accordingly a weak
predictor of past and present patterns of selection. Scaling of genitals
varies across taxonomic groups, but negative allometry of genitals in
insects and spiders is a consistent pattern. Lastly, I find indications
that terrestrial organisms have an overall different scaling of
morphological traits compared to aquatic species.