Seasonality and Age is Positively Related to Brain Size in Andrew’s Toad (Bufo andrewsi)

• Published in: Evolutionary biology Vol. 42; no. 3; pp. 339 - 348
• Main Authors: Jiang, Ao, Zhong, Mao Jun, Xie, Min, Lou, Shang Ling, Jin, Long, Robert, Jehle, Liao, Wen Bo
• Format: Journal Article
• Language: English
• Published: New York Springer US 01-09-2015; Springer; Springer Nature B.V
• Subjects: Age; Animal Genetics and Genomics; Benzocaine; Biomedical and Life Sciences; Body size; Brain; Brain architecture; Bufo andrewsi; Cerebellum; Cognitive ability; Developmental Biology; Ecology; Evolutionary Biology; Human Genetics; Life Sciences; Olfactory bulb; Olfactory nerve; Research Article; Telencephalon; Toads; Cognitive Buffer Hypothesis; Expensive Brain Framework; Andrew’s toad; Brain size; Seasonality; Individual age
• ISSN: 0071-3260; 1934-2845
• DOI: 10.1007/s11692-015-9329-4

The Expensive Brain Framework (EBF) and the Cognitive Buffer Hypothesis are commonly used to explain inter- and intraspecific variation in brain size and brain architecture. Using Andrew’s toad (
Bufo andrewsi
) as a model species, we investigated whether brain attributes in amphibians are shaped by the interplay between age and the length of the activity season as determined by altitude and latitude. We found significant differences in absolute and relative brain volume across 12 populations. Supporting the EBF, we observed a positive correlation between absolute and relative brain volume with season length. In particular, populations experiencing long seasons were characterized by having relatively large olfactory nerve and optic tecta. Relative, but not absolute, brain volume was also positively correlated with individual age. When accounting for the effects of body size and brain volume, however, the size of different brain structures (olfactory nerve, olfactory bulbs, telencephalon, optic tecta and cerebellum) was independent from age. Taken together, our findings are largely in agreement with the EBF to determine brain size variation in Andrew’s toad.