Data from: Comparative analyses of reproductive structures in harvestmen (Opiliones) reveal multiple transitions from courtship to precopulatory antagonism

Explaining the rapid, species-specific diversification of reproductive
structures and behaviors is a long-standing goal of evolutionary biology,
with recent research tending to attribute reproductive phenotypes to the
evolutionary mechanisms of female mate choice or intersexual conflict.
Progress in understanding these and other possible mechanisms depends, in
part, on reconstructing the direction, frequency and relative timing of
phenotypic evolution of male and female structures in species-rich clades.
Here we examine evolution of reproductive structures in the leiobunine
harvestmen or “daddy long-legs” of eastern North America, a monophyletic
group that includes species in which males court females using nuptial
gifts and other species that are equipped for apparent precopulatory
antagonism (i.e., males with long, hardened penes and females with
sclerotized pregenital barriers). We used parsimony- and Bayesian
likelihood-based analyses to reconstruct character evolution in
categorical reproductive traits and found that losses of ancestral
gift-bearing penile sacs are strongly associated with gains of female
pregenital barriers. In most cases, both events occur on the same internal
branch of the phylogeny. These coevolutionary changes occurred at least
four times, resulting in clade-specific designs in the penis and
pregenital barrier. The discovery of convergent origins and/or
enhancements of apparent precopulatory antagonism among closely related
species offers an unusual opportunity to investigate how major changes in
reproductive morphology have occurred. We propose new hypotheses that
attribute these enhancements to changes in ecology or life history that
reduce the duration of breeding seasons, an association that is consistent
with female choice, sexual conflict, and/or an alternative evolutionary
mechanism.