Anuran mating systems: The role of climate, life history traits, and sex ratio

There is a great diversity of mating systems in anurans, but the factors
driving this diversity remain uncharted. Here, using phylogenetic
comparative methods, we explore which factors are related to the presence
of mating systems in anurans and examine evolutionary patterns. We
collected data for 717 anuran species and evaluated the effects of
climate, temporal breeding pattern, sex ratios, terrestriality, and
fecundity on their mating systems. Scramble competition and simultaneous
polyandry occur more in species with aquatic eggs and oviposition sites,
which have larger clutches, in habitats with high temperature seasonality,
and low annual temperature/precipitation. Direct benefits occur often in
species with terrestrial larger eggs and smaller clutches, which have
terrestrial or sheltered oviposition sites, and in habitats with lower
temperature seasonality. Only lek and polygyny were correlated with sex
ratios. Most mating systems are strongly influenced by shared evolutionary
history and are linked to the evolution of reproductive modes. Climate and
sex ratios seem to play a role in the plasticity of mating systems, as a
species can have more than one. Finally, our study represents a
considerable advance toward understanding the anuran mating system
evolution.