Data from: Bateman gradients in hermaphrodites: an extended approach to quantify sexual selection

Sexual selection is often quantified using Bateman gradients, which
represent sex-specific regression slopes of reproductive success on mating
success and thus describe the expected fitness returns from mating more
often. Although the analytical framework for Bateman gradients aimed at
covering all sexual systems, empirical studies are biased towards
separate-sex organisms, probably because important characteristics of
other systems remain incompletely treated. Our synthesis complements the
existing Bateman gradient approach with three essential reproductive
features of simultaneous hermaphrodites. First, mating in one sex may
affect fitness via the opposite sex, e.g. through energetic trade-offs. We
integrate cross-sex selection effects and show how they help
characterizing sexually mutualistic versus antagonistic selection. Second,
male and female mating successes may be correlated, complicating the
interpretation of Bateman gradients. We show how to quantify the impact of
this correlation on sexual selection, and propose a Principal Component
Analysis on male and female mating success to facilitate interpretation.
Third, self-fertilization is accounted for by adding selfed progeny as a
separate category of reproductive success to analyzes of Bateman
gradients. Finally, using a worked example from the snail Biomphalaria
glabrata, we illustrate how the extended analytical framework can further
our understanding of sexual selection.