Artificial selection on male genitalia length alters female brain size

Séverine D. Buechel, Isobel Booksmythe, Alexander Kotrschal, Michael D. Jennions, Niclas Kolm

Research output: Contribution to journalArticleResearchpeer-review

Abstract

Male harassment is a classic example of how sexual conflict over mating leads to sex-specific behavioural adaptations. Females often suffer significant costs from males attempting forced copulations, and the sexes can be in an arms race over male coercion. Yet, despite recent recognition that divergent sex-specific interests in reproduction can affect brain evolution, sexual conflict has not been addressed in this context. Here, we investigate whether artificial selection on a correlate of male success at coercion, genital length, affects brain anatomy in males and females. We analysed the brains of eastern mosquitofish (Gambusia holbrooki), which had been artificially selected for long or short gonopodium, thereby mimicking selection arising from differing levels of male harassment. By analogy to how prey species often have relatively larger brains than their predators, we found that female, but not male, brain size was greater following selection for a longer gonopodium. Brain subregion volumes remained unchanged. These results suggest that there is a positive genetic correlation between male gonopodium length and female brain size, which is possibly linked to increased female cognitive ability to avoid male coercion. We propose that sexual conflict is an important factor in the evolution of brain anatomy and cognitive ability.

Original languageEnglish
Article number20161796
Number of pages6
JournalProceedings of the Royal Society B: Biological Sciences
Volume283
Issue number1843
DOIs
Publication statusPublished - 30 Nov 2016
Externally publishedYes

Keywords

  • Brain evolution
  • Gambusia holbrooki
  • Gonopodium
  • Male harassment
  • Sexual conflict
  • Sexual dimorphism

Cite this

Buechel, Séverine D. ; Booksmythe, Isobel ; Kotrschal, Alexander ; Jennions, Michael D. ; Kolm, Niclas. / Artificial selection on male genitalia length alters female brain size. In: Proceedings of the Royal Society B: Biological Sciences. 2016 ; Vol. 283, No. 1843.
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Artificial selection on male genitalia length alters female brain size. / Buechel, Séverine D.; Booksmythe, Isobel; Kotrschal, Alexander; Jennions, Michael D.; Kolm, Niclas.

In: Proceedings of the Royal Society B: Biological Sciences, Vol. 283, No. 1843, 20161796, 30.11.2016.

Research output: Contribution to journalArticleResearchpeer-review

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