Female Reproductive Cycles of Phrynocephalus przewalskii (Lacertilia:Agamidae) in the Tengger Desert,China

The timing of reproduction can significantly affect an offspring＇s fitness, thereby also influencing the fitness of the parents, especially in species inhabiting extreme environments, such as deserts. Female reproductive cycles in Phrynocephalus przewalskii were studied from April to September 2008. Significant cycles of gonadal volume were found in all studied populations and the cycles were similar among the various populations. Females began vitellogenesis in April and contained oviductal eggs form May to June. Gonad volume decreased significantly in July and reached minimum volume from August to September. The follicular growth was negatively correlated with increasing precipitation and temperature in all populations. Hatching occurs during summer and early fall, when most of the annual rainfall occurs. Mean clutch size based on all populations was 2.7 ± 0.9 SE （n = 71）.

Sexual Dimorphism of Head Size in Phrynocephalus przewalskii: Testing the Food Niche Divergence Hypothesis

Sexual size dimorphism （SSD） is a general phenomenon in lizards, and can evolve through sexual selection or natural selection. But natural selection, which was thought to operate mainly through reducing the competition be- tween the two sexes （niche divergence hypothesis）, gave rise to a lot of controversy. We tested the niche divergence hypothesis in the toad-headed lizard Phrynocephalus przewalskii by comparing diet composition and prey sizes between males and females. The species was found to be sexual dimorphic, with males having relatively larger snout-vent length, head width, head length, and tail length, while females have relatively larger abdomen length. Based on analysis of 93 studied stomachs, a total of 1359 prey items were identified. The most common prey items were formicid, lygaeid and tenebrionid. The two sexes did not differ in the relative proportions of prey size categories they consumed and the dietary overlap based on prey species was high （O = 0.989）. In addition, the meal size, the volume or any maximal dimension of the largest prey item in the stomach was not explained by the sexes. According to our results, food niche divergence might not play an important role in the SSD evolution ofP. przewalskii.

Geographic Variation in Clutch and Egg Size for the Lizard Phrynocephalus przewalskii(Squamata:Agamidae)

In order to tease apart proximate vs. ultimate sources of variation in reproductive strategy, studies have increasingly focused on populations rather than species as the unit of interest. The reproductive parameters of Phrynocephalus przewalskii （Agamidae） in different populations within the same phylogenetic clade were compared in this study. Female SVL, clutch size, egg volume and clutch volume varied significantly among populations. With increase in latitude, clutch size increased, while egg size decreased. Relatively fewer but larger eggs were produced with increasing of population density. Food availability had positive effects on clutch size, but no effect on egg size. Our result indicated that latitude, food availability and population density may be the proximate factors affecting the reproductive parameters ofP. przewalskii.

Sex Ratio and Sexual Size Dimorphism in a Toad-headed Lizard, Phrynocephalus guinanensis

Phrynocephalus guinanensis has sexual dimorphism in abdominal coloration, but its ontogenetic development of sexual size dimorphism （SSD） is unknown. Using mark-recapture data during four days each year from August from 2014 to 2016, we investigated the development of sex ratios, SSD, sex-specific survivorship and growth rates in a population of P guinanensis. Our results indicated that the sex ratio of males to females was 1：2.8. Males had a lower survival rate （6%） than females （14%） across the age range from hatchling to adult, which supported the discovered female-biased sex ratio potentially associated with the low survival rate of males between hatchlings and juveniles. Male-biased SSD in tail length and head width existed in adults rather than in hatchling or juvenile lizards. The growth rates in body dimensions were undistinguishable between the sexes during the age from hatchling to juvenile, but the growth rate in head length from juvenile to adult was significantly larger in males than females. Average growth rate of all morphological measurements from hatchling to juvenile were larger compared with corresponding measurements from juvenile to adult, but only being significant in tail length, head width, abdomen length in females and snout-vent length in males. We provided a case study to strengthen our understanding of the important life history traits on how a viviparous lizard population can survive and develop their morphology in cold climates.

Variation in egg and clutch size of the Black Redstart(Phoenicurus ochruros) at the northeastern edge of the Qinghai-Tibetan Plateau

Background: In birds, the trade-off between the quality and number of nestlings is one of the most important theories of the evolution of life history of birds, which is closely related with climate. We investigated variation in egg and clutch size of the Black Redstart(Phoenicurus ochruros) on the northeastern edge of the Qinghai-Tibetan Plateau in order to explore and test the relation between egg size and clutch size and the rules governing the variation in these two components with climate change.Methods: We monitored each located nest daily to determine the exact laying order of the eggs and measured their sizes. The variations in egg volume and clutch size between 2008 and 2009 were studied by independent sample t tests. The difference in egg volume in the sequence of the laying order was tested by Kendall's W test and we employed Pearson correlations to investigate the relation between egg size and laying order. All statistical analyses were performed with IBM SPSS Statistics, version 19.0Results: In 2008, the mean egg volume of the Black Redstart was 2.40 and clutch size wer± 0.20 cm^3(n e 2.26 = 50), and the mean clutch size 4.90 ± 0.57(n = 11). In 2009, the mean egg volumeation between eg± 0.18 cm^3(n g size and layin= 74) and 5.20 g order(r ± 0.26(n = 15) respectively. We found a significantly positive correl, while egg size was strongly and negatively correlated with clutch size(r = 0.397, p = 0.030) smaller eggs but a larger clutch in a brood in a resource-rich year, w= h-0.274, p ereas large= 0.002). Black Redstarts tend to layr eggs but smaller clutches are produced in a harsh year.Conclusions: The Black Redstart adopted a "brood survival strategy" to ensure that more offspring could survive. The Black Redstart' trade-off in egg volume and clutch size would guarantee that it will gain maximum benefit in any case.

Limited gene flow and partial isolation phylogeography of Himalayan snowcock Tetraogallus himalayensis based on part mitochondrial D-loop sequences

Himalayan snowcock Tetraogallus himalayensis are distributed in alpine and subalpine areas in China. We used mi- tochondrial DNA control-region data to investigate the origin and past demographic change in sixty-seven Himalayan snowcock T. himalayensis. The fragments of 1155 nucleotides from the control region of mitochondrial DNA were sequenced, and 57 poly- morphic positions defined 37 haplotypes. A high level of genetic diversity was detected in all populations sampled and may be associated isolation of the mountains and habitat fragmentation and deterioration from Quaternary glaciations. In the phylogenetic tree, all haplotypes grouped into four groups： clade A （Kunlun Mountains clade）, clade B （Northern Qinghai-Tibetan Plateau clade）, clade C （Tianshan Mountains clade） and clade D （Kalakunlun Mountains clade）. We found a low level of gene flow and significant genetic differentiation among all populations. Based on divergence time we suggest that the divergence of Himalayan snowcock occurred in the middle Pleistocene inter-glaciation, and expansion occurred in the glaciation. Analysis of mtDNA D-loop sequences confirmed demographic population expansion, as did our non-significant mismatch distribution analysis. In conclusion, limited gene flow and a pattern of partial isolation phylogeographic was found in geographic populations of T. hima- layansis based on the analysis on mtDNA D-loop sequences [Current Zoology 57 （6）： 758-767, 2011].

Population structure and demographic history of the chukar partridge Alectoris chukar in China

Pleistocene climate fluctuations have shaped the patterns of genetic diversity observed in extant species. Although the effects of recent glacial cycles on genetic diversity have been well studied on species in Europe and North America, genetic legacy of species in the Pleistocene in north and northwest of China where glaciations was not synchronous with the ice sheet development in the Northern Hemisphere or or had little or no ice cover during the glaciations＇ period, remains poorly understood. Here we used phylogeographic methods to investigate the genetic structure and population history of the chukar partridge Alec- toris chukar in north and northwest China. A 1,152 - 1,154 bp portion of the mtDNA CR were sequenced for all 279 specimens and a total number of 91 haplotypes were defined by 113 variable sites. High levels of gene flow were found and gene flow esti- mates were greater than 1 for most population pairs in our study. The AMOVA analysis showed that 81% and 16% of the total genetic variability was found within populations and among populations within groups, respectively. The demographic history of chukar was examined using neutrality tests and mismatch distribution analyses and results indicated Late Pleistocene popula- tion expansion. Results revealed that most populations of ehukar experienced population expansion during 0.027 - 0.06 Ma. These results are at odds with the results found in Europe and North America, where population expansions occurred after Last Glacial Maximum （LGM, 0.023 to 0.018 Ma）. Our results are not consistent with the results from avian species of Tibetan Plateau, either, where species experienced population expansion following the retreat of the extensive glaciation period （0.5 to 0.175 Ma）

Asymmetrical introgression patterns between rusty-necklaced partridge (Alectoris magna) and chukar partridge (Alectoris chukar) in China

The rusty-necklaced partridge(Alectoris magna)and the chukar partridge(Alectoris chukar)are the most com­mon gamebirds in northern China.Previous comparisons of mitochondrial DNA(mtDNA)have revealed an in­trogression phenomenon between 2 species of partridge in the Liupan Mountain region of China.mtDNA is ma­ternally inherited,making it difficult to determine the origin of parental genes.We assessed the genetic variation and gene flow between these 2 species of partridges using 8 microsatellite loci as neutral diagnostic markers in 171 samples from the hybrid zone.Our data revealed an extensive divergence of genetic structure between populations of rusty-necklaced partridges and chukar partridges.In this study,we found that 19 samples had been previously morphologically identified as rusty-necklaced partridge were genetically identified as hybrids through Bayesian analysis using STRUCTURE analysis.These hybrids exhibited a mosaic of alleles that were derived from both parental lineages.However,chukar partridges did not present the genotype of the rusty-neck­laced partridge.Thus,our findings demonstrate that the hybridization between the 2 species was the result of asymmetrical introgression,with gene flow occurring only from the chukar partridge to the rusty-necklaced par­tridge.In addition,we also note the high linkage disequilibrium in populations of the rusty-necklaced partridge.These results indicate that although unidirectional introgression did not reduce genetic diversity of the Alectoris partridges,it affected the balance of gene flow between populations.The data from microsatellite DNA prompt­ed our concern about the genetic integrity of the rusty-necklaced partridge.

Habitat selection of the Tibetan Snow Cock Tetraogallus tibetanus in the spring in Lhasa

The habitat selection of Tibetan Snow Cocks in shrub vegetation was investigated in Lhasa,Tibet,China,between March and April,2005.Fourteen parameters were measured.These include altitude,slope,slope aspect,slope position,vegetation cover,plant type and other environmental parameters.Results show that Snow Cocks favor foraging in areas where vegetation cover was small and close to the residents’houses.Supplementary food supplied by humans has caused Snow Cocks to decrease their foraging range.Snow Cocks also favor roosting in areas with low vegetation,sparse grass,short grass,large rocks and close to houses.The Snow Cocks’activity in the study areas show a close relationship with human activities.