Yuan-Ting Jin and Nai-Fa Liu
Phrynocephalus vlangalii, a toad-headed viviparous sand lizard, is endemic in the Northern Tibet (Qinghai) Plateau in China. Lizards were collected from 14 localities along the large altitudinal gradient (2289-4565 m a.s.l) to analyze the variation of reproductive traits among localities. Both litter size and mean offspring (scaled embryo) mass were positively correlated with female snout-vent length (SVL). Females produced fewer and larger offspring with increasing elevation when the effect of body size (SVL) was removed. This strategy may possibly be correlated with early survival and growth of offspring. The decreased litter size cline along altitudinal gradient might be correlated with more anatomical constraints at higher altitudes. The lizard has lower coefficient of variation (CV) of litter size at higher environments. Moreover, females from higher elevations had less reproductive investment (relative litter mass, RLM). Study concluded that P. vlangalii fit into the common pattern of higher elevation animals that have smaller clutches of larger offspring and lower reproductive effort.
Nai-fa Liu, Jian-You Zhao, Wei Zhao, Ming-qin Shao and Sen Song
Regurgitated pellets (n = 584) of Long-eared Owl (Asio otus) were collected for three seasons from Gansu Endangered Animal Research Center, Gansu Province, China. From these pellets, a total of 1011 individual prey items – representing seven species of rodents and two undetermined species of birds and one undetermined sorex-species – were identified. Long-eared Owls depend mainly on small mammals both based on prey numbers (95.5%) and prey biomass (97.0%). The composition of the diet of Long-eared Owls varied significantly among seasons by frequency and by biomass. The individual species groups indicated significant variation among seasons for Mus musculus, Meriones meridianus, Cricetulus barabensis, Phodopus roborovskii, Dipus sagitta and Rattus norvegicus by biomass. And the difference of seasonal variation of prey items were significant but not for Mus musculus by frequency. Based on prey numbers, Mus musculus was the main food item (50.5%) in its diet; this species was most common in autumn (56.9%) and least common during spring (36.7%). Main prey species, based on prey biomass, was Rattus norvrgicus which comprised 27.5% of total biomass from our pellet samples. The mean length of tibias of mammals in pellets of Long-eared Owls was 18.6 ± 5.4 mm. Long-eared Owls utilize a wide range of prey items in respect to their habitats. Results suggest that Long-eared Owls are selective predators at some levels.