Fast life-histories are associated with larger brain size in killifishes

• Published in: Evolution Vol. 75; no. 9; pp. 2286 - 2298
• Main Authors: Sowersby, Will, Eckerström-Liedholm, Simon, Kotrschal, Alexander, Näslund, Joacim, Rowinski, Piotr, Gonzalez-Voyer, Alejandro, Rogell, Björn
• Format: Journal Article
• Language: English
• Published: United States Wiley 01.09.2021; Oxford University Press
• Subjects: Animals; Body Size; Brain; brain size; Coevolution; Cognitive ability; Cyprinodontidae; Ecology; Ekologi; Fundulidae; killifish; Killifishes; life-history; Ontogeny; Organ Size; ORIGINAL ARTICLE; trade-off; Vertebrates; body size; trade-off; killifish; life-history; coevolution; brain size
• DOI: 10.1111/evo.14310
• ISSN: 0014-3820; 1558-5646

The high energetic demands associated with the vertebrate brain are proposed to result in a trade-off between the pace of lifehistory and relative brain size. However, because both life-history and brain size also have a strong relationship with body size, any associations between the pace of life-history and relative brain size may be confounded by coevolution with body size. Studies on systems where contrasts in the pace of life-history occur without concordant contrasts in body size could therefore add to our understanding of the potential coevolution between relative brain size and life-history. Using one such system–21 species of killifish –we employed a common garden design across two ontogenetic stages to investigate the association between relative brain size and the pace of life-history. Contrary to predictions, we found that relative brain size was larger in adult fast-living killifishes, compared to slow-living species. Although we found no differences in relative brain size between juvenile killifishes. Our results suggest that fast-and slow-living killifishes do not exhibit the predicted trade-off between brain size and life-history. Instead, fast and slow-living killifishes could differ in the ontogenetic timing of somatic versus neural growth or inhabit environments that differ considerably in cognitive demands.