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It is becoming increasingly obvious that species' courtship is more complex than originally thought. Hundreds of studies have described courtship systems focusing on a single trait, but we know many species have multiple signaling methods (Hebets, 2005). Multimodal courtship describes a composition of signals covering different sensory modalities, including visual, auditory, and tactile. Is having multiple courtship methods better than just one? This study focused on two types of signaling- sexual dichromatism and the presence of vocal sacs- in the family Hylidae. The goal was to determine the preferred signaling methods and their evolutionary relationship. We predicted that most species use multimodal courtship systems. It will be more likely that species evolve a secondary courtship signaling method to increase the range of sensory stimulation. Data on sexual dimorphism and vocal sacs was collected for 203 species in the Hylidae family from peer-reviewed literature. We analyzed each character trait using ancestral state reconstruction methods in Rstudio. To test whether the evolution of vocal sacs and dichromatism is correlated, we used Pagel's Method and BayesTraits (Revel 2012, Pagel 1994, Pagel et al 2004). The results revealed that the use of unimodal signaling in the form of vocal sacs was the preferred system. When given a multimodal system, there was a higher likelihood of losing a method to preserve a unimodal system than gaining an additional method. Certain combinations of multimodal signaling must be too costly evolutionary-wise to be found in nature. Elaborate courtship displays such as bright colors have the potential to attract predators. The role of each signaling component is still unclear, as are the influences that promote uni and multimodal courtship signaling systems (Mitoyen, 2019).

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Logan, UT


courtship systems, Hylidae, multimodal courtship, sexual dimorphism


Life Sciences

Multimodel Courtship Signaling in The Family Hylidae

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