Data from: You sound like my Mr. Right: female frogs choose size-assortative mates through acoustic features

1. Amplexus is a distinctive mating strategy in the reproductive life cycle of amphibians, during which females may adopt assortative or random mating strategies in selecting mates. Prior to amplexus, male frogs usually emit acoustic signals to attract females, emphasizing the predominant role of acoustic communication in anuran reproductive process. However, it has remained unclear whether males' acoustic signals significantly affect female’s preference for male size.2. In this study, we investigated the mating strategy of Fejervarya multistriata, a paddy frog, and examined whether females can use acoustic signals to locate assortatively-sized males. We measured the body size of frog amplexus pairs to explore the relationship between female and male body size. We then recorded male advertisement calls and employed stepwise algorithm to optimize a linear model for predicting male size based on acoustic properties, identifying the properties that most effectively predict male size. We also conducted two-choice arena phonotaxis experiments in which females were simultaneously exposed to male calls representing different body sizes.3. Our findings showed that: (1) F. multistriata could use size-assortative mating as a reproductive strategy. (2) The optimal acoustic-morphometric model, incorporating the first frequency band and note interval that both negatively correlated with male size, could accurately predict male body size. (3) Female frogs exhibited preferences for calls representing size-assortative males.4. Therefore, we suggested that F. multistriata females can use acoustic signals to discriminate between males of different sizes, supporting an acoustically-mediated size-assortative mating strategy. In conclusion, this study provides valuable insights into the mechanisms of size-assortative mate choice in amphibians and contributes to understanding the role of acoustic signals in reproductive processes.