Spawning location is linked to the relative size of olfactory nerves in anurans.

The brain is the most important organ associated with demands on cognitive ability, and selection pressures have been implicated to explain variation in brain size and brain architecture in a wide range of taxa. Using phylogenetic comparative methods, we studied the effect of spawning location (terrestrial, lentic and lotic) on variation in the size of different brain parts among 43 Chinese anuran species. Spawning location was not significantly associated with relative brain size, and there were no links between spawning location and independent contrasts in size of the olfactory bulbs, telencephalon, optic tecta and cerebellum. However, the independent contrasts in size of the olfactory nerves differed significantly among the three types of spawning location. Our findings provide evidence that the brain structures underlying olfaction are linked to lifehistory attributes required for spawning in specific habitat types. [ABSTRACT FROM AUTHOR]