naa a22 4500 528786989 20180924065502.0 cr unu---uuuuu 180924e20120119xx s 000 0 eng 10.3929/ethz-b-000047262 doi 10.1371/journal.pone.0030055 doi (ETHRESEARCH)oai:www.research-collection.ethz.ch:20.500.11850/47262 Extreme Sexual Brain Size Dimorphism in Sticklebacks: A Consequence of the Cognitive Challenges of Sex and Parenting? [Elektronische Daten] [Alexander Kotrschal, Katja Räsänen, Bjarni K. Kristjánsson, Mike Senn, Niclas Kolm] PLoS ONE Open access ethresearch Selection pressures that act differently on males and females produce numerous differences between the sexes in morphology and behaviour. However, apart from the controversial report that males have slightly heavier brains than females in humans, evidence for substantial sexual dimorphism in brain size is scarce. This apparent sexual uniformity is surprising given that sexually distinct selection pressures are ubiquitous and that brains are one of the most plastic vertebrate organs. Here we demonstrate the highest level of sexual brain size dimorphism ever reported in any vertebrate: male three-spined stickleback of two morphs in an Icelandic lake have 23% heavier brains than females. We suggest that this dramatic sexual size dimorphism is generated by the many cognitively demanding challenges that males are faced in this species, such as an elaborate courtship display, the construction of an ornate nest and a male-only parental care system. However, we consider also alternative explanations for smaller brains in females, such as life-history trade-offs. Our demonstration of unprecedented levels of sexual dimorphism in brain size in the three-spined stickleback implies that behavioural and life-history differences among the sexes can have strong effects also on neural development and proposes new fields of research for understanding brain evolution. Creative Commons Attribution 3.0 Unported http://creativecommons.org/licenses/by/3.0 ethresearch Kotrschal Alexander joint author Räsänen Katja joint author Kristjánsson Bjarni K. joint author Senn Mike joint author Kolm Niclas joint author PLoS ONE Lawrence, KS, USA : Public Library of Science 7 (1), p. e30055 1932-6203 http://hdl.handle.net/20.500.11850/47262 text/html WWW-Backlink auf das Repository (Open access) 1 Journal Article ethresearch ETHRESEARCH 856 40 http://hdl.handle.net/20.500.11850/47262 text/html WWW-Backlink auf das Repository (Open access) ETHRESEARCH 700 1- Kotrschal Alexander joint author ETHRESEARCH 700 1- Räsänen Katja joint author ETHRESEARCH 700 1- Kristjánsson Bjarni K. joint author ETHRESEARCH 700 1- Senn Mike joint author ETHRESEARCH 700 1- Kolm Niclas joint author ETHRESEARCH 773 0- PLoS ONE Lawrence, KS, USA : Public Library of Science 7 (1), p. e30055 1932-6203 BK010053 XK010053 XK010000 ETHRESEARCH ETHRESEARCH ETHRESEARCH Journal Article Open access