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Converging or diverging? Shape coevolution between a sperm-dependent asexual and its sexual hosts.
Waldir M Berbel-Filho1,2,3, Michael Tobler4,5,6, Tyler Reich2,3
1Department of Biology, University of West Florida, Pensacola, FL 32514, USA.
Proceedings. Biological Sciences
|July 1, 2025
Summary
Asexual Amazon mollies exhibit unique shape variations, differing from their sexual hosts in a host-specific manner. This supports character displacement in sexual-asexual systems.
Area of Science:
- Evolutionary biology
- Genetics
- Ecology
Background:
- Asexual species can evolve and impact sexual species.
- Gynogenesis, a mode of asexual reproduction, involves sperm from a different species.
- The Amazon molly (Poecilia formosa) is a gynogenetic species utilizing sperm from sexual mollies.
Purpose of the Study:
- To investigate shape variation in asexual Amazon mollies relative to their sexual hosts.
- To test hypotheses of sexual mimicry, character displacement, and random variation.
- To understand eco-evolutionary dynamics in a sexual-asexual system.
Main Methods:
- Analysis of morphological shape variation in wild Amazon mollies and their sexual hosts (Poecilia latipinna and Poecilia mexicana).
- Testing three distinct hypotheses: sexual mimicry, character displacement, and a null hypothesis of random variation.
Main Results:
- Significant shape variation was observed in Amazon mollies.
- Amazon mollies displayed host-specific shape differences.
- Findings indicated that Amazon mollies resemble the non-host sexual species, supporting character displacement.
Conclusions:
- Asexual species can exhibit complex eco-evolutionary dynamics with sexual hosts.
- Character displacement occurs at the interspecific level in this sexual-asexual molly system.
- Morphological divergence in asexuals is influenced by interactions with sexual hosts.
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