title: Evolution of brain-body allometry in Lake Tanganyika cichlids.
abstract: Brain size is strongly associated with body size in all vertebrates. This relationship has been hypothesized to be an important constraint on adaptive brain size evolution. The essential assumption behind this idea is that static (i.e., within species) brain-body allometry has low ability to evolve. However, recent studies have reported mixed support for this view. Here, we examine brain-body static allometry in Lake Tanganyika cichlids using a phylogenetic comparative framework. We found considerable variation in the static allometric intercept, which explained the majority of variation in absolute and relative brain size. In contrast, the slope of the brain-body static allometry had relatively low variation, which explained less variation in absolute and relative brain size compared to the intercept and body size. Further examination of the tempo and mode of evolution of static allometric parameters confirmed these observations. Moreover, the estimated evolutionary parameters indicate that the limited observed variation in the static allometric slope could be a result of strong stabilizing selection. Overall, our findings suggest that the brain-body static allometric slope may represent an evolutionary constraint in Lake Tanganyika cichlids.
authors.affiliation: Evolutionary Biology Centre, Department of Ecology and Genetics/Animal Ecology, Uppsala University, Norbyvägen 18D, SE-75236, Uppsala, Sweden. masa.tsuboi@gmail.com.
authors.forename: Masahito
authors.initials: M
authors.lastname: Tsuboi
authors.affiliation: Department of Zoology/Ethology, Stockholm University, Svante Arrhenius väg 18B, SE-10691, Stockholm, Sweden.
authors.forename: Alexander
authors.initials: A
authors.lastname: Kotrschal
authors.affiliation: Department of Zoology/Ethology, Stockholm University, Svante Arrhenius väg 18B, SE-10691, Stockholm, Sweden.
authors.forename: Alexander
authors.initials: A
authors.lastname: Hayward
authors.affiliation: Department of Zoology/Ethology, Stockholm University, Svante Arrhenius väg 18B, SE-10691, Stockholm, Sweden.
authors.forename: Severine Denise
authors.initials: SD
authors.lastname: Buechel
authors.affiliation: IFM Biology, Linköping University, Campus Valla, SE-58183, Linköping, Sweden.
authors.forename: Josefina
authors.initials: J
authors.lastname: Zidar
authors.affiliation: IFM Biology, Linköping University, Campus Valla, SE-58183, Linköping, Sweden.
authors.forename: Hanne
authors.initials: H
authors.lastname: Løvlie
authors.affiliation: Department of Zoology/Ethology, Stockholm University, Svante Arrhenius väg 18B, SE-10691, Stockholm, Sweden.
authors.forename: Niclas
authors.initials: N
authors.lastname: Kolm
mesh_terms: D000818:Animals; D005075:Biological Evolution; D049628:Body Size; D001921:Brain / Q000033:anatomy & histology*; D023681:Cichlids / Q000033:anatomy & histology*; D060106:Lakes; D009929:Organ Size; D010802:Phylogeny; D015024:Zambia
keywords: Allometry; Lake Tanganyika cichlid; brain evolution; brain-body allometry; constraints; phylogenetic comparative analysis