Does brain size affect mate choice? An experimental examination in pygmy halfbeaks

Area of Science:

• Behavioral Ecology
• Neuroscience
• Animal Behavior

Background:

• Female mate choice is crucial for reproductive success and often relies on evaluating male sexual ornaments.
• Cognitive abilities, potentially linked to brain size, may influence the evaluation of these ornaments.
• The relationship between brain size and mate choice, however, remains under-investigated in many species.

Purpose of the Study:

• To investigate the effect of brain size on mate preferences in the pygmy halfbeak (Dermogenys collettei).
• To determine if relative brain size or telencephalon size influences female mate choice based on male sexual ornamentation.

Main Methods:

• External brain measurements were validated as a proxy for internal brain size in pygmy halfbeaks.
• Females were presented with males differing in sexual ornamentation (red coloration area).
• Female mate preferences were assessed in relation to female brain size and the difference in male ornamentation.

Main Results:

• Neither total relative brain size nor relative telencephalon size significantly affected female mate preference.
• The degree of difference in male sexual ornamentation influenced female choice.
• Females preferred males with smaller red coloration areas when the difference in ornamentation between males was large.

Conclusions:

• Brain size does not appear to be a primary driver of mate choice in pygmy halfbeaks.
• Mate choice is complex and influenced by the magnitude of differences in sexual ornaments.
• Further research should consider multiple factors influencing mate selection beyond cognitive proxies.