Relationship between brain size and digestive tract length support the expensive-tissue hypothesis in Feirana quadranus

The brain is among the most energetically costly organs in vertebrate body, while size of varies within species. expensive-tissue hypothesis (ETH) predicts that increasing another organ, such as gut, should compensate for cost a small brain. Here, ETH was tested by analyzing relationship between variation and digestive tract length Swelled-vented frog ( Feirana quadranus ). A total 125 individuals across 10 populations ranging from 586 to 1,702 m a.s.l. Qinling-Daba Mountains were sampled. With increase altitude, decreases increases. Different regions do not change their relative consistent manner. sizes telencephalon cerebellum decrease with olfactory nerve increases its at high altitudes. However, bulb optic tectum have no significant altitude. After controlling snout-vent (SVL), negative correlation could be found F. . Therefore, intraspecific follows general patterns this results suggest annual mean temperature precipitation are environmental factors influencing adaptive evolution length. This study also suggests food composition, activity times, habitat complexity potential reasons driving