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Laryngeal Demasculinization in Wild Cane Toads Varies with Land Use
Sara Zlotnik1,2, Marcos Gridi-Papp3, Ximena E Bernal4,5
1Department of Biological Sciences, Purdue University, 915 West State Street, West Lafayette, IN, 47907, USA. zlotniks@ufl.edu.
Ecohealth
|October 20, 2019
Summary
Endocrine-disrupting chemicals near sugarcane fields demasculinized male cane toads. This wildlife endocrine disruption affected reproductive traits, including the larynx crucial for mating calls.
Area of Science:
- Environmental Toxicology
- Wildlife Reproductive Biology
- Ecotoxicology
Background:
- Anthropogenic factors, such as endocrine-disrupting chemicals (EDCs), impact wildlife reproduction.
- Research on EDCs often overlooks secondary sexual traits vital for mating signals and reproductive success.
- The larynx in anurans (frogs and toads) is a sexually dimorphic trait, larger in males and essential for vocalizations.
Purpose of the Study:
- To investigate if male cane toads (Rhinella marina) near Florida sugarcane fields exhibit demasculinized larynges compared to those near urban areas.
- To assess the impact of potential anthropogenic factors on both primary and secondary sexual traits in wild anuran populations.
Main Methods:
- Comparative analysis of laryngeal morphology (mass, vocal cord length, dilator muscle width) in male cane toads from sugarcane versus urban environments.
- Examination of correlations between primary (e.g., testes) and secondary (e.g., larynx, skin) sexual traits to understand the extent of demasculinization.
Main Results:
- Male cane toads inhabiting sugarcane regions showed reduced relative laryngeal mass, vocal cord length, and dilator muscle width compared to urban counterparts.
- Evidence of demasculinization was observed in both primary and secondary sexual traits.
- Strong correlations indicated that demasculinization affected multiple organs, including testes, larynx, and skin, in a coordinated manner.
Conclusions:
- Anurans exposed to sugarcane field environments exhibit demasculinized reproductive systems.
- Endocrine disruption extends to secondary sexual traits like the larynx, impacting mating capabilities.
- Anthropogenic factors associated with sugarcane cultivation are likely causes of observed reproductive system demasculinization in cane toads.
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