Females alter their mate preferences depending on hybridization risk

Area of Science:

• Evolutionary Biology
• Behavioral Ecology
• Speciation Research

Background:

• Hybridization often results in low-fitness offspring, making it evolutionarily costly.
• Individuals are expected to avoid mating with heterospecifics when the costs of hybridization are high.

Purpose of the Study:

• To investigate if female spadefoot toads (*Spea multiplicata*) alter mate preferences for conspecific male signals in the presence of heterospecifics.
• To understand how hybridization risk influences sexual selection on male signals.

Main Methods:

• Experimental manipulation of auditory cues in simulated choruses.
• Presentation of conspecific male signals against backgrounds with and without heterospecific signals.
• Observation and analysis of female mate choice preferences.

Main Results:

• Females preferred conspecific male signals dissimilar to heterospecifics when both were present.
• In the absence of heterospecifics, some females shifted preference to exaggerated conspecific signals (high-quality mates).
• No population-level preference for exaggerated signals was observed without heterospecifics due to variable female responses.

Conclusions:

• Hybridization risk significantly alters mate choice patterns and sexual selection.
• Reproductive barriers, like female mate choice, can be context-dependent.
• Female mate choice plays a crucial role in maintaining species boundaries and influencing evolutionary trajectories.