Data from: Frequency-dependent selection on female morphs driven by pre-mating interactions with males

Species showing color polymorphisms—the presence of two or more
genetically determined color morphs within a single population—are
excellent systems for studying the selective forces driving the
maintenance of genetic diversity. Despite a shortage of empirical
evidence, it is often suggested that negative frequency-dependent mate
preference by males (or diet choice by predators) results in fitness
benefits for the rare female morph (or prey type). Moreover, most studies
have focused on the male (or predator) behavior in these systems and
largely overlooked the importance of female (or prey) resistance behavior.
Here, we provide the first explicit test of the role of
frequency-dependent and frequency-independent intersexual interactions in
female polymorphic damselflies. We identify the stage of the mating
sequence when frequency-dependent selection is likely to act by comparing
indexes of male mate preference when the female has little (females
presented on sticks), moderate (females in cages), and high (females free
to fly in the field) ability to avoid male mating attempts.
Frequency-dependent male preferences were found only in those experiments
where females had little ability to resist male harassment, indicating
that premating interactions most likely drive negative frequency-dependent
selection in this system. In addition, by separating frequency-dependent
male mating preference from the baseline frequency-independent component,
we reconcile the seemingly contradictory results of previous studies and
highlight the roles of both forms of selection in maintaining the
polymorphism at a given equilibrium. We conclude that considering
interactions among all players—here, males and females—is crucial to fully
understanding the mechanisms underlying the maintenance of genetic
polymorphisms in the wild.