| Climate warming has an extremely important impact on the survival and reproduction of ectotherms,and the related research is a frontier hot spot in the field of animal ecology.Qinghai toad-headed agamid(Phrynocephalus vlangalii)distributed on plateau,as the reptile with the largest altitude span among the oviparous lizards in China,is an ideal model species to study how ectotherms responds to climate warming.In this study,the low-altitude(2600m)and high-altitude(3600m)populations of the lizard P.vlangalii distributed in the Dangjinshan region of Gansu province were taken as the objects.Based on the experimental enclosures constructed in the field,a climate warming simulation experiment concerning to the warming control of the high-altitude and low-altitude lizard populations was carried out to explore the effects of temperature increase on their reproductive life history and offspring fitness,and to reveal their response and adaptation strategies to climate warming.The results showed that:(1).Monitoring the air temperature at 10 cm above ground and the underground temperature at 30 cm depth showed that the daily average air temperature and the daily average underground temperature were 6.75℃ and 5.46℃ higher at the low than high altitudes respectively,3.37℃ and 2.76℃ higher at the warming than control enclosures of the low altitude respectively,3.63℃ and 1.56℃ higher at the warming than control enclosures of the high altitude respectively.The warming treatment of the experimental enclosures could better simulate the temperature conditions under the background of the future climate warming.(2).There was no significant difference in body size of lizards between the warming and control enclosures at the same altitude.The sexual dimorphism of the lizard was obvious,adult females were larger than adult males.The lizard individuals were larger at the high than low altitudes.(3).The lizard populations gave birth earlier at the low than high altitudes,but the high altitude population gave birth more intensively.Increase of temperature made the pregnant females give birth 6 days earlier at the low altitude and 11 days earlier at the high altitude.(4).No matter the high-altitude population or the low-altitude population,the experimental warming did not significantly change the litter size,litter mass,neonate mass per litter and relative litter mass of the mother.However,these reproduction parameters were significantly lower in the low-altitude population with high environmental temperature than in its high-altitude population.(5).No matter the populations at the high or low altitudes,temperature increase could improve the growth rate and locomotion ability of the lizard offspring.From the two indexes of growth and locomotion performance,temperature increase could improve the fitness of lizard offspring.(6).Compared with the low altitude,lizard mothers at the high altitude with low ambient temperature had a late start time but a short and concentrated litter duration.At the high altitude,they tended to produce large litter and its offspring grew slowly,while at the low altitude,they tended to produce small litter and its offspring grew rapidly.Under different environmental temperatures,the populations of P.vlangalii at the high and the low altitudes showed different reproductive strategies. |
