The Herpetological Journal

pp. 149-154
Authors: Lu, Hong-Liang; Jiang, Chuan-Quan & Ji, Xiang

Abstract: Locomotor impairment during pregnancy can be attributed to physical burden or physiological changes associated with pregnancy. However, the degree to which physical and physiological changes affect reproductive costs likely varies between species. Here, we used the Qinghai toad-headed lizard (Phrynocephalus vlangalii) as a model to assess locomotor costs during pregnancy and the relative impact of physical and physiological effects in pregnant viviparous lizards. The locomotor costs of pregnancy were pronounced: sprint speed decreased gradually throughout pregnancy, reached a minimum at parturition and increased slowly thereafter. The reduced speed in pregnant females was not related to relative litter mass. Compared with the locomotion of non-reproductive females or males, pregnant females exhibited lower speeds and shorter stride lengths. These results suggest that, despite having a physical effect on locomotor performance, physiological changes associated with pregnancy likely play a major role in locomotor impairment in pregnant P. vlangalii.

Keywords: PHRYNOCEPHALUS VLANGALII, REPRODUCTIVE COSTS, STRIDE LENGTH, AGAMIDAE, LOCOMOTOR PERFORMANCE, PHYSICAL BURDEN