The Effects of Prey Items Diversity and Digestible Materials in Stomach on Digestive Tract Length in Hylarana guentheri

Difference in environmental condition shapes variation in digestive tract length in evolutionary process.In particular,environmental difference results in variation in food resource among different habitats,and thereby affecting energy intake and energy allocation.The digestive theory predicts that animals foraging high indigestible materials of stomach contents can promote the increased gut dimensions.Here,we studied variation in digestive tract and gut length across six Hylarana guentheri populations at different altitudes and latitudes to test the prediction of the digestive theory.We found that altitude and latitude did not affect variation in relative size of digestive tract and gut among populations.We also found that relative size of digestive tract and gut did not be correlated with diversity of prey items,but negatively correlated with proportion of digestible materials.Our findings suggest that individuals foraging less digestible materials display relatively longer digestive tract than individuals foraging more digestible materials.