Color Change in Neotropical Yellow Toads: Do Males Compete Based on their Breeding Coloration?

Standing

Undergraduate

Type of Proposal

Oral Research Presentation

Challenges Theme

Open Challenge

Faculty

Faculty of Science

Faculty Sponsor

Dr. Dan Mennill and Dr. Stephanie Doucet

Proposal

Visual signals play a vital role in sexual selection in anurans. Females often use visual cues such as elaborate colors and patterns to select their ideal mate, however, male competition has shown to be the most prevalent evolutionary mechanism driving mate choice in animals. Neotropical Yellow Toad (Incilius luetkenii) males have been observed to express a dynamic visual signal during brief, explosive mating events. For just a few short hours, males display a vibrant yellow coloration until actively engaging in reproduction, after which they revert to a female-like cryptic brown color. Recent studies suggest that males use color as a sex identification signal during these explosive events, and that females do not selectively interact with males based on their coloration, but we have yet to determine whether this trait may function as an intrasexual signal during competitive interactions. If intrasexual selection is driving rapid color changes in male Yellow Toads, we hypothesize that males will differentially compete with other males based on their coloration. To test this, we placed a male Yellow Toad along with two hyper-realistic stimuli of amplectant pairs into the different apexes of a triangular arena. One stimulus male exhibited bright yellow coloration and the other a dull coloration. If color is an indicator of male quality, we predict that males will initiate physical competition with the duller male model more frequently than with the brighter, and potentially higher quality, male model. Our research will enhance our understanding of the function of conspicuous visual cues in anurans.

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Color Change in Neotropical Yellow Toads: Do Males Compete Based on their Breeding Coloration?

Visual signals play a vital role in sexual selection in anurans. Females often use visual cues such as elaborate colors and patterns to select their ideal mate, however, male competition has shown to be the most prevalent evolutionary mechanism driving mate choice in animals. Neotropical Yellow Toad (Incilius luetkenii) males have been observed to express a dynamic visual signal during brief, explosive mating events. For just a few short hours, males display a vibrant yellow coloration until actively engaging in reproduction, after which they revert to a female-like cryptic brown color. Recent studies suggest that males use color as a sex identification signal during these explosive events, and that females do not selectively interact with males based on their coloration, but we have yet to determine whether this trait may function as an intrasexual signal during competitive interactions. If intrasexual selection is driving rapid color changes in male Yellow Toads, we hypothesize that males will differentially compete with other males based on their coloration. To test this, we placed a male Yellow Toad along with two hyper-realistic stimuli of amplectant pairs into the different apexes of a triangular arena. One stimulus male exhibited bright yellow coloration and the other a dull coloration. If color is an indicator of male quality, we predict that males will initiate physical competition with the duller male model more frequently than with the brighter, and potentially higher quality, male model. Our research will enhance our understanding of the function of conspicuous visual cues in anurans.