• <tr id="yyy80"></tr>
  • <sup id="yyy80"></sup>
  • <tfoot id="yyy80"><noscript id="yyy80"></noscript></tfoot>
  • 99热精品在线国产_美女午夜性视频免费_国产精品国产高清国产av_av欧美777_自拍偷自拍亚洲精品老妇_亚洲熟女精品中文字幕_www日本黄色视频网_国产精品野战在线观看 ?

    Oxygen Availability Affects Behavioural Thermoregulation of Turtle Embryos

    2024-01-02 06:49:20LiangLIANGandWeiguoDU
    Asian Herpetological Research 2023年4期

    Liang LIANG and Weiguo DU

    Key Laboratory of Animal Ecology and Conservation Biology,Institute of Zoology,Chinese Academy of Sciences,Beijing 100101,China

    Abstract Extending recent findings that reptile embryos seek optimal temperatures inside eggs for thermoregulation,our study demonstrates that this thermoregulatory behaviour can be affected by the amount of oxygen available to an embryo.We exposed embryos of a freshwater turtle (Mauremys reevesii) to two heat sources (an optimal temperature of 30°C and a high temperature of 33°C)under three different oxygen levels-hypoxia(12%O2),normoxia(21%O2)and hyperoxia(30%O2)-and quantified the interactive effects of temperature and oxygen availability on embryonic thermoregulatory behaviour.Our results demonstrated that,in both thermal treatments,embryos exposed to hypoxia did not move as close to the heat source and therefore selected lower temperatures than those exposed to normoxia or hyperoxia.Embryos may select low temperatures under hypoxic conditions to decrease oxygen consumption and therefore alleviate the negative impact of hypoxic stress.

    Keywords behavioural thermoregulation,embryonic development,heat tolerance,hypoxia,reptile

    1.Introduction

    Unlike endotherms that maintain high body temperature via internal thermogenesis (Angillettaet al.,2010),most ectothermic animals behaviourally thermoregulate to utilize environmental heat sources,and thereby achieve optimal body temperatures that maximize their functional performance(Angillettaet al.,2002).Behavioural thermoregulation by ectotherms is very important for their daily activity,but may be affected by a number of biotic and abiotic factors(e.g.food,competition,predation and oxygen availability)(Herczeget al.,2008;Rusch and Angilletta,2017;Wood and Glass,1991).For example,many ectotherms select lower body temperatures as an adaptive response to protect vital organs under hypoxic stress (Wiggins and Frappell,2002;Wood and Glass,1991).Exploring the interaction of ecological factors on behavioural thermoregulation is critical for understanding how ectotherms cope with unpredictable environmental change.

    Behavioural thermoregulation not only occurs at postembryonic stages,but also occurs in embryos of oviparous amniotes(Duet al.,2011;Liet al.,2014;Yeet al.,2021;Zhaoet al.,2013b).The adaptive significance of this behaviour was under debate(Corderoet al.,2018;Du and Shine,2022;Shine and Du,2018;Telemecoet al.,2016).Thermoregulatory behavior is expected to be conducive for successful embryonic development (Duet al.,2011).A recent study showed that behavioral thermoregulation by turtle embryos influenced offspring sex ratio,which expands the range of nest temperatures producing an equal sex ratio (Yeet al.,2019).Nonetheless,the adaptive significance of this behavior warrants further studies.

    In the Chinese three-keeled pond turtle(Mauremys reevesii),when eggs were exposed to lateral heating,embryos moved towards a heat source at an optimal developmental temperature of 30°C,but moved away from a heat source at a stressful temperature of 33°C(Zhaoet al.,2013b).Given that the thermal preference of adult ecotherms can be lowered on exposure to hypoxia (Wood and Glass,1991),we hypothesize that reptilian embryonic thermoregulatory behaviour may also be affected by oxygen availability.Further,we predict that embryos will select lower body temperatures when exposed to hypoxia than when exposed to normoxia and hyperoxia.To test this hypothesis,we conducted a manipulation experiment with a two-factor design [three oxygen levels (hypoxia,normoxia,and hyperoxia) × two thermal environments (optimal and high temperatures)]to identify the effects of oxygen availability and temperature on the thermoregulatory behaviour of freshwater turtle embryos.

    2.Material and Methods

    2.1.Study species and egg collectionThe Chinese threekeeled pond turtle is a freshwater turtle distributed in southern and central China as well as southeastern Asia.Females lay eggs at the bank of rivers or ponds with vegetation cover from May to August.Mean nest temperatures of this species at semi-natural breeding sites range from 25.7°C to 30.1°C depending on the season(Yeet al.,2019).In 2016,we collected a total of 112 fertilizedM.reevesiieggs from a private turtle farm in Zhejiang,China.These eggs were weighed(mean±SD,egg mass=7.357±0.932 g),measured(mean±SD,egg length=32.88 ± 2.15 mm),and then incubated in boxes (220 mm × 100 mm × 80 mm) with moist vermiculite(-220 kPa,1 g water/1 g vermiculite,Zhaoet al.,2013a)at a constant room temperature of 28°C in normoxic conditions(21%O2).

    2.2.Experimental design and thermoregulation behaviorWe commenced the following experiments when embryos had reached developmental stages 16-17(Greenbaum,2002).First,we located the initial position of an embryo in each egg by candling and then marked the position on the eggshells (Zhaoet al.,2013b).The eggs were then incubated individually in small plastic boxes filled with moist vermiculite (-220 kPa).We randomly assigned these boxes to the six treatments with three oxygen levels[hypoxia(12%O2),normoxia(21%O2)or hyperoxia(30%O2)]and two lateral heating treatments(30°C and 33°C,optimal and high temperature temperatures for embryonic development,respectively).We sealed plastic boxes with eggs into a 30 L polybag,which was supplied with gas containing different levels of oxygen.The polybags were then exposed to lateral heating of 30°C or 33°C.To achieve egg-surface temperatures of 30°C or 33°C,we adjusted the distance between the electronic heating mats (45 watt,300 mm ×700 mm)and the polybags accordingly(Zhaoet al.,2013b).After seven days during which the distance of embryo movements is substantial and readily measured (Zhaoet al.,2013b),the final position of each embryo was detected by candling.We recorded the distances between the initial and final positions of an embryo along the long axis of the egg with a vernier caliper (± 0.01 mm).The distance embryos moved towards or away from a heat source was used as a measure of the behavioural thermoregulatory ability of embryos.

    During incubation,oxygen concentrations in the gas polybags were achieved by mixing oxygen with nitrogen.The gas in each polybag was renewed every day to maintain the desired oxygen concentration.During gas renewal,freshwater was added to the vermiculite to maintain the water potential of moist vermiculite.The process of gas renewal and freshwater addition was completed in under 2 minutes.We sampled gas from polybags periodically before and after each renewal.The sampled gas was checked by O2and CO2analyzers(FC-10A and CA-10A;Model TR3,Sable Systems,Henderson,NV,USA)with O2and CO2sensors(UI-2;Model TR3,Sable Systems,Henderson,NV,USA).During the experiment,the O2level of the gas in each polybag was kept within 2% of the three required treatment values (12%,21%or 30%O2),and the CO2level was kept below 0.2%.

    2.3.Data analysisWe used two-way ANOVAs to analyze the effect of lateral heating treatment and oxygen concentration on the distance of embryonic movements towards or away from the heat source.Given the significant interaction between heating treatment and oxygen concentration,ANOVAs were used to analyze the effect of oxygen concentration on embryonic movement in each thermal treatment,and post-hoc tests (Tukey's test) were used to identify differences among oxygen treatments.

    3.Results

    The distances moved by embryonic Chinese three-keeled pond turtles were significantly affected by temperature(F1,106=28.996,P<0.0001),oxygen concentration (F2,106=25.008,P<0.0001),and the interaction between temperature and oxygen availability (F2,106=3.084,P<0.05).In general,embryos from the 30°C treatment moved greater distances towards the heat source than those from the 33°C treatment,which did not move as far or as close to the heat source(Figure 1).The distance that embryos moved towards the heat source decreased as oxygen concentration declined in both lateral heating treatments of 30°C(F1,56=10.061,P<0.001)and 33°C(F1,50=21.814,P<0.0001).Specifically,in the 30°C treatment embryos exposed to normoxia and hyperoxia moved towards the heat source,but those exposed to hypoxia did not;in the 33°C treatment embryos exposed to hyperoxia moved towards the heat source,but those exposed to hypoxia and normoxia moved away from the heat source (Figure 1).Therefore,the distance embryos moved towards a heat source decreased as oxygen concentration declined in both lateral heating treatments of 30°C and 33°C.

    Figure 1 Effects of oxygen concentration and thermal treatment on the behavioural thermoregulation of embryos in the Chinese three-keeled pond turtle (Mauremys reevesii).Hypoxia,normoxia,and hyperoxia are 12%,21% and 30% oxygen concentrations,respectively.The numbers above the error bars are sample sizes.Means with different alphabets above the error bars are statistically different among different oxygen concentrations in each temperature treatment.The dots below and above the boxes are outliers.

    4.Discussion

    Our study concurs with the conclusion from a previous study(Zhaoet al.,2013b)that turtle embryos at normal oxygen levels move towards a heat source when exposed to an optimal temperature of 30°C,but move away from a heat source when exposed to a high temperature of 33°C.More importantly,consistent with our prediction,we demonstrated that oxygen availability during development significantly affects behavioural thermoregulation by turtle embryos;embryos exposed to hypoxia did not move as close to a heat source and,therefore,selected lower temperatures than embryos exposed to normoxia or hyperoxia in both thermal treatments.

    This phenomenon of hypoxia-induced hypothermia has also been seen in post-embryonic stages of ectothermic animals (Petersenet al.,2003;Wiggins and Frappell,2002;Wood and Glass,1991).In adult reptiles,downregulation of their thermoregulatory setpoint is triggered by the release of adenosine due to a decrease in arterial oxygen(Petersenet al.,2003).The benefits of the regulated decrease in body temperature under hypoxia include improving oxygen loading in the lungs,reducing energetically costly cardiac hyperactivity,and decreasing oxygen consumption given the thermal sensitivity of metabolism(Sunet al.,2015;Wanget al.,1998).Therefore,embryonic selection of lower temperatures under hypoxia is a beneficial strategy that may alleviate the negative impact of hypoxic stress on development.

    Reptile eggs in a nest likely experience hypoxia when unpredictable climate events such as excess rainfall and flooding occur,and when metabolism of microbes and eggs depletes the oxygen within the nest chamber(Ackerman and Lott,2004;Seymouret al.,1986).When facing hypoxia,reptile embryos may increase chorioallantoic membrane vascular density,shunt blood flow away from non-exchanging areas,increase cardiac output and carrying capacity of blood O2,or enlarge the opaque white patch (Corona and Warburton,2000;Tanget al.,2018).In addition to these physiological adjustments in response to hypoxia,our study demonstrates the adaptive response of embryonic thermoregulatory behaviour to hypoxia in turtles,expanding our knowledge of the capabilities that embryos possess to cope with unpredictable environments.

    Hypoxia decreases the heat tolerance of ectotherms,because decreasing oxygen supply cannot meet the increasing demands of oxygen consumption when environmental temperatures increase,as suggested by the hypothesis of oxygen-and capacity-limited thermal tolerance(P?rtner and Knust,2007).Recent studies have demonstrated that oxygen supply significantly affects heat tolerance of reptile embryos,including turtles and lizards (Lianget al.,2015;Smithet al.,2015).Our results suggest that hypoxia not only decreases heat tolerance,but also the thermal preference of embryos.However,further studies are needed to fully understand the interactive effects of oxygen availability and temperature on the behaviour and physiology of ectothermic embryos.

    AcknowledgementsWe thank Bo ZHAO,Teng LI,Liang MA and Baojun SUN for their help in the laboratory.This work was supported by grants from the National Natural Science Foundation of China(32030013,31821001).

    在线播放无遮挡| 十分钟在线观看高清视频www| 国产综合精华液| 曰老女人黄片| 狠狠精品人妻久久久久久综合| 男人爽女人下面视频在线观看| 日韩伦理黄色片| 男人操女人黄网站| 99热国产这里只有精品6| 97超视频在线观看视频| 18禁裸乳无遮挡动漫免费视频| 国产欧美日韩综合在线一区二区| av在线观看视频网站免费| 欧美日韩成人在线一区二区| 欧美日韩成人在线一区二区| 七月丁香在线播放| 成人无遮挡网站| 18禁观看日本| 国产成人精品福利久久| 亚洲怡红院男人天堂| 免费大片18禁| 亚洲国产成人一精品久久久| 国产精品.久久久| 91国产中文字幕| 精品久久国产蜜桃| 99热全是精品| 在线精品无人区一区二区三| 亚洲美女黄色视频免费看| 国产视频首页在线观看| 性色av一级| 熟女av电影| 视频在线观看一区二区三区| 欧美性感艳星| 国产精品蜜桃在线观看| 久久久久久久久久久免费av| 日日撸夜夜添| 亚洲国产最新在线播放| 日日啪夜夜爽| 日本黄大片高清| 亚州av有码| 春色校园在线视频观看| 大又大粗又爽又黄少妇毛片口| 成人亚洲精品一区在线观看| 麻豆成人av视频| 91精品国产国语对白视频| 亚洲av免费高清在线观看| 99久久精品国产国产毛片| 精品一区二区三区视频在线| 熟女人妻精品中文字幕| 久久午夜福利片| 亚洲精品日本国产第一区| 美女国产高潮福利片在线看| 精品国产国语对白av| a 毛片基地| 香蕉精品网在线| 在线观看一区二区三区激情| a级片在线免费高清观看视频| 夫妻性生交免费视频一级片| 欧美精品人与动牲交sv欧美| 午夜av观看不卡| 久久久久视频综合| 18禁在线播放成人免费| 人妻人人澡人人爽人人| 欧美3d第一页| 男女无遮挡免费网站观看| 性高湖久久久久久久久免费观看| 母亲3免费完整高清在线观看 | 亚洲欧洲国产日韩| 久久精品久久精品一区二区三区| 纯流量卡能插随身wifi吗| 黄色一级大片看看| 日韩三级伦理在线观看| 51国产日韩欧美| 成人午夜精彩视频在线观看| 国产精品偷伦视频观看了| 亚洲av电影在线观看一区二区三区| 午夜激情福利司机影院| 久久这里有精品视频免费| av网站免费在线观看视频| 亚洲欧洲日产国产| 亚洲精品456在线播放app| 日韩,欧美,国产一区二区三区| av免费观看日本| 国产高清有码在线观看视频| 老女人水多毛片| 精品国产露脸久久av麻豆| 草草在线视频免费看| 嫩草影院入口| 亚洲少妇的诱惑av| 久久久亚洲精品成人影院| 黑人猛操日本美女一级片| 日韩一区二区三区影片| av有码第一页| 自拍欧美九色日韩亚洲蝌蚪91| 五月天丁香电影| 一区二区日韩欧美中文字幕 | 亚洲精品色激情综合| 国产精品熟女久久久久浪| 一级毛片aaaaaa免费看小| 久久免费观看电影| 黑人欧美特级aaaaaa片| 亚洲图色成人| 人成视频在线观看免费观看| 欧美日韩视频高清一区二区三区二| 国产精品久久久久久久久免| 国产探花极品一区二区| 亚洲精品aⅴ在线观看| 性色av一级| 飞空精品影院首页| av在线app专区| 国产成人一区二区在线| 国产av码专区亚洲av| 午夜av观看不卡| 国产成人精品婷婷| 国产成人免费无遮挡视频| 久久精品久久精品一区二区三区| 日韩免费高清中文字幕av| 在线观看www视频免费| 美女中出高潮动态图| 免费av不卡在线播放| 国产精品成人在线| 亚洲av福利一区| 91精品国产国语对白视频| a级毛色黄片| 精品一区二区三卡| 国产成人精品在线电影| 亚洲色图 男人天堂 中文字幕 | 日韩电影二区| 夫妻性生交免费视频一级片| 大陆偷拍与自拍| 婷婷色麻豆天堂久久| 天堂8中文在线网| 亚洲不卡免费看| 免费观看av网站的网址| 成人18禁高潮啪啪吃奶动态图 | 只有这里有精品99| 啦啦啦视频在线资源免费观看| 99久久人妻综合| 我的老师免费观看完整版| 久久久精品94久久精品| 黑人巨大精品欧美一区二区蜜桃 | 在线观看三级黄色| 熟女人妻精品中文字幕| 亚洲经典国产精华液单| 亚洲欧洲日产国产| 老熟女久久久| 午夜日本视频在线| 成人无遮挡网站| 在线观看免费视频网站a站| 汤姆久久久久久久影院中文字幕| videossex国产| 大又大粗又爽又黄少妇毛片口| 超色免费av| 免费观看无遮挡的男女| 免费人成在线观看视频色| 大香蕉久久成人网| 美女cb高潮喷水在线观看| 99久久精品一区二区三区| 免费人妻精品一区二区三区视频| 最后的刺客免费高清国语| 成年女人在线观看亚洲视频| 又大又黄又爽视频免费| 亚洲五月色婷婷综合| 大香蕉久久网| 激情五月婷婷亚洲| 国产亚洲精品第一综合不卡 | 精品一区在线观看国产| 亚洲精品国产av蜜桃| 全区人妻精品视频| 黄色怎么调成土黄色| 亚洲精品一区蜜桃| 亚洲一区二区三区欧美精品| 午夜福利视频精品| 国产淫语在线视频| 精品一区二区免费观看| 精品一区二区三区视频在线| 国产免费现黄频在线看| 国产亚洲欧美精品永久| 免费黄网站久久成人精品| 寂寞人妻少妇视频99o| 国产日韩一区二区三区精品不卡 | 超色免费av| 丰满迷人的少妇在线观看| 色吧在线观看| 国产有黄有色有爽视频| 日本av免费视频播放| 久久久精品94久久精品| av女优亚洲男人天堂| 国产日韩欧美亚洲二区| 亚洲国产精品一区二区三区在线| 黑人猛操日本美女一级片| 欧美亚洲日本最大视频资源| 欧美+日韩+精品| 日本免费在线观看一区| 欧美日韩精品成人综合77777| 国产高清国产精品国产三级| 在线亚洲精品国产二区图片欧美 | 一本久久精品| 人人妻人人爽人人添夜夜欢视频| 国产男女内射视频| 亚洲图色成人| 国产精品成人在线| 熟女人妻精品中文字幕| 全区人妻精品视频| 91久久精品国产一区二区成人| 久久婷婷青草| 美女国产视频在线观看| 国产精品久久久久久久久免| 日韩av在线免费看完整版不卡| 少妇猛男粗大的猛烈进出视频| 美女中出高潮动态图| 国产一区二区在线观看日韩| 狂野欧美激情性bbbbbb| 国产精品久久久久久久电影| 国产av国产精品国产| 美女中出高潮动态图| 久久精品国产自在天天线| 91精品伊人久久大香线蕉| 久久精品久久久久久久性| 国产高清三级在线| 久久女婷五月综合色啪小说| 最黄视频免费看| 欧美日韩国产mv在线观看视频| 午夜影院在线不卡| 国产男女超爽视频在线观看| 日本午夜av视频| 国产男女内射视频| 99久久综合免费| 丝袜喷水一区| 黄片无遮挡物在线观看| 在现免费观看毛片| 最近中文字幕2019免费版| 制服人妻中文乱码| 久久这里有精品视频免费| 草草在线视频免费看| 国产日韩欧美视频二区| 亚洲中文av在线| 七月丁香在线播放| 日韩亚洲欧美综合| 亚洲av在线观看美女高潮| 不卡视频在线观看欧美| 免费观看在线日韩| 亚洲综合色惰| 成年人午夜在线观看视频| 欧美激情 高清一区二区三区| 久久久久久久久大av| 在线观看www视频免费| 男女免费视频国产| av国产久精品久网站免费入址| kizo精华| 2018国产大陆天天弄谢| 精品亚洲成国产av| 亚洲国产av新网站| 亚洲av不卡在线观看| 人成视频在线观看免费观看| 99久久精品国产国产毛片| 国产欧美亚洲国产| 人人澡人人妻人| 一级毛片aaaaaa免费看小| 亚洲美女视频黄频| 国产欧美日韩一区二区三区在线 | 亚洲精品中文字幕在线视频| 最新的欧美精品一区二区| 高清欧美精品videossex| 国产欧美亚洲国产| 观看美女的网站| 精品一品国产午夜福利视频| 久久久久视频综合| 精品亚洲成a人片在线观看| 亚洲美女黄色视频免费看| 亚洲国产色片| 国产免费福利视频在线观看| 丰满少妇做爰视频| 看十八女毛片水多多多| 日日摸夜夜添夜夜爱| 日韩在线高清观看一区二区三区| 久久久国产一区二区| 日日啪夜夜爽| 国产一区二区在线观看av| 免费看av在线观看网站| 免费高清在线观看视频在线观看| 亚洲人与动物交配视频| 午夜福利网站1000一区二区三区| 亚洲av免费高清在线观看| 色94色欧美一区二区| 观看美女的网站| 精品人妻在线不人妻| 免费不卡的大黄色大毛片视频在线观看| 在线亚洲精品国产二区图片欧美 | 精品人妻一区二区三区麻豆| av免费观看日本| 99热全是精品| 婷婷色麻豆天堂久久| a级毛片黄视频| 在线天堂最新版资源| 91精品国产国语对白视频| 人妻一区二区av| 精品久久国产蜜桃| 在线观看免费视频网站a站| 成人国产av品久久久| 中文欧美无线码| 国产精品99久久99久久久不卡 | 在线观看www视频免费| 伊人亚洲综合成人网| 高清欧美精品videossex| 色94色欧美一区二区| 精品少妇久久久久久888优播| 80岁老熟妇乱子伦牲交| 欧美国产精品一级二级三级| 成人午夜精彩视频在线观看| 97在线视频观看| 成人综合一区亚洲| 爱豆传媒免费全集在线观看| 97在线人人人人妻| 日韩伦理黄色片| 免费看av在线观看网站| 国产精品无大码| 国产乱来视频区| 日韩一本色道免费dvd| 亚洲av免费高清在线观看| 欧美日韩综合久久久久久| 国产成人免费无遮挡视频| 99国产精品免费福利视频| 激情五月婷婷亚洲| 蜜桃在线观看..| 精品久久国产蜜桃| 两个人免费观看高清视频| 亚洲综合色网址| 又黄又爽又刺激的免费视频.| 色婷婷av一区二区三区视频| 91成人精品电影| 极品人妻少妇av视频| 欧美日韩亚洲高清精品| 国产熟女午夜一区二区三区 | av免费在线看不卡| 高清毛片免费看| 美女主播在线视频| 在线亚洲精品国产二区图片欧美 | av在线老鸭窝| 亚洲精品色激情综合| 涩涩av久久男人的天堂| 97超视频在线观看视频| 亚洲国产毛片av蜜桃av| 一本色道久久久久久精品综合| 97在线人人人人妻| 十分钟在线观看高清视频www| 老熟女久久久| 女人精品久久久久毛片| 午夜影院在线不卡| 九色成人免费人妻av| 日本欧美视频一区| 国产精品人妻久久久影院| 国产亚洲精品第一综合不卡 | av不卡在线播放| 欧美日韩综合久久久久久| 嫩草影院入口| 在线天堂最新版资源| 精品久久久精品久久久| 制服丝袜香蕉在线| 亚洲欧美中文字幕日韩二区| 国产永久视频网站| 久久久久国产精品人妻一区二区| 亚洲一区二区三区欧美精品| 在线观看www视频免费| 日本与韩国留学比较| 天堂俺去俺来也www色官网| 伊人亚洲综合成人网| a 毛片基地| 国产永久视频网站| 青春草国产在线视频| 蜜臀久久99精品久久宅男| 国产日韩欧美视频二区| 亚洲熟女精品中文字幕| 三上悠亚av全集在线观看| 99热国产这里只有精品6| 久久久久久人妻| 最黄视频免费看| 狠狠精品人妻久久久久久综合| 99热国产这里只有精品6| 久久久久久人妻| 精品国产一区二区久久| 高清在线视频一区二区三区| 五月玫瑰六月丁香| 一区二区日韩欧美中文字幕 | 热re99久久国产66热| 五月开心婷婷网| 国产成人a∨麻豆精品| videosex国产| 日韩免费高清中文字幕av| 免费观看av网站的网址| 黄色视频在线播放观看不卡| 蜜臀久久99精品久久宅男| 丰满饥渴人妻一区二区三| 欧美日韩在线观看h| 91精品国产九色| 26uuu在线亚洲综合色| 成年av动漫网址| 国产精品秋霞免费鲁丝片| 丝瓜视频免费看黄片| 亚洲伊人久久精品综合| av在线老鸭窝| 国国产精品蜜臀av免费| 高清视频免费观看一区二区| 久久久久精品久久久久真实原创| 十八禁高潮呻吟视频| 一级毛片 在线播放| 久久久久久久亚洲中文字幕| 国产精品欧美亚洲77777| 97超碰精品成人国产| 黄片播放在线免费| 亚洲无线观看免费| 91在线精品国自产拍蜜月| 女人久久www免费人成看片| 一区二区三区免费毛片| 满18在线观看网站| 国产日韩欧美视频二区| 日韩中字成人| 乱码一卡2卡4卡精品| 国产男人的电影天堂91| 国产av一区二区精品久久| 搡老乐熟女国产| 一个人看视频在线观看www免费| 视频中文字幕在线观看| 精品少妇黑人巨大在线播放| 大片免费播放器 马上看| 欧美日韩一区二区视频在线观看视频在线| 美女国产高潮福利片在线看| 国产黄频视频在线观看| 高清毛片免费看| 日韩大片免费观看网站| 久热这里只有精品99| 丰满迷人的少妇在线观看| 久久鲁丝午夜福利片| 午夜福利视频精品| 寂寞人妻少妇视频99o| 亚洲欧美一区二区三区国产| 成人黄色视频免费在线看| 欧美成人午夜免费资源| 自拍欧美九色日韩亚洲蝌蚪91| av视频免费观看在线观看| 国产成人av激情在线播放 | 黑人欧美特级aaaaaa片| 久久精品人人爽人人爽视色| 老司机影院成人| 汤姆久久久久久久影院中文字幕| 狠狠精品人妻久久久久久综合| 99久久中文字幕三级久久日本| 日韩精品免费视频一区二区三区 | av国产久精品久网站免费入址| 制服丝袜香蕉在线| 三级国产精品片| 精品国产乱码久久久久久小说| 中文字幕人妻熟人妻熟丝袜美| 国产男人的电影天堂91| 欧美激情 高清一区二区三区| 黄色毛片三级朝国网站| 国产成人精品久久久久久| 亚洲欧美日韩另类电影网站| 国产极品粉嫩免费观看在线 | 亚洲欧洲国产日韩| 黄色欧美视频在线观看| 国国产精品蜜臀av免费| 在线观看免费视频网站a站| 免费观看a级毛片全部| 午夜视频国产福利| 亚洲精品,欧美精品| 一级黄片播放器| 视频在线观看一区二区三区| 欧美xxxx性猛交bbbb| 男女啪啪激烈高潮av片| 最近手机中文字幕大全| 国产成人精品在线电影| 亚洲高清免费不卡视频| 成人免费观看视频高清| 久久97久久精品| 亚洲国产日韩一区二区| 制服人妻中文乱码| 亚洲人成网站在线观看播放| 少妇的逼好多水| 日韩视频在线欧美| 天堂8中文在线网| 成人亚洲欧美一区二区av| 老司机影院成人| 久久99蜜桃精品久久| 精品亚洲乱码少妇综合久久| √禁漫天堂资源中文www| 99国产精品免费福利视频| 一区二区三区乱码不卡18| 天天躁夜夜躁狠狠久久av| 如何舔出高潮| 免费不卡的大黄色大毛片视频在线观看| 午夜免费男女啪啪视频观看| 久久韩国三级中文字幕| 天天操日日干夜夜撸| 欧美亚洲日本最大视频资源| 久久久久视频综合| 欧美人与善性xxx| 国产免费一区二区三区四区乱码| 国产永久视频网站| 亚洲人成网站在线播| 啦啦啦在线观看免费高清www| 91精品一卡2卡3卡4卡| 18禁在线无遮挡免费观看视频| 久久久久久久久久久久大奶| 国产爽快片一区二区三区| 国产亚洲欧美精品永久| 人妻制服诱惑在线中文字幕| 女性被躁到高潮视频| 午夜av观看不卡| 亚洲国产毛片av蜜桃av| 天堂8中文在线网| 全区人妻精品视频| 国产亚洲一区二区精品| 99久久中文字幕三级久久日本| 97超碰精品成人国产| 18禁在线无遮挡免费观看视频| a级毛片在线看网站| 亚洲人成网站在线播| 日本猛色少妇xxxxx猛交久久| 免费大片黄手机在线观看| 亚洲av免费高清在线观看| 欧美精品一区二区免费开放| 国产精品麻豆人妻色哟哟久久| 制服人妻中文乱码| 高清午夜精品一区二区三区| 韩国高清视频一区二区三区| 国产精品国产三级国产av玫瑰| 人妻一区二区av| 我要看黄色一级片免费的| av播播在线观看一区| 丝袜喷水一区| 黄色怎么调成土黄色| 国产免费福利视频在线观看| 欧美 日韩 精品 国产| 大片电影免费在线观看免费| 黄色一级大片看看| 精品人妻熟女av久视频| 亚洲怡红院男人天堂| 国产精品国产av在线观看| 精品国产国语对白av| 亚洲精品久久久久久婷婷小说| 日日啪夜夜爽| 亚洲情色 制服丝袜| 亚洲第一区二区三区不卡| 亚洲成人一二三区av| 精品午夜福利在线看| 国产一区二区三区综合在线观看 | 久久久久久久国产电影| 欧美国产精品一级二级三级| 国产男女超爽视频在线观看| 建设人人有责人人尽责人人享有的| 亚洲av男天堂| 欧美激情国产日韩精品一区| 女性被躁到高潮视频| 日韩伦理黄色片| 两个人免费观看高清视频| 国产免费一区二区三区四区乱码| 久久99精品国语久久久| 亚洲欧美色中文字幕在线| 久久精品久久精品一区二区三区| 91久久精品电影网| 丝瓜视频免费看黄片| 搡老乐熟女国产| 中文字幕人妻丝袜制服| 91精品国产九色| 有码 亚洲区| 欧美最新免费一区二区三区| 国产精品一二三区在线看| 久久久久视频综合| 欧美激情极品国产一区二区三区 | 久久亚洲国产成人精品v| 中文字幕精品免费在线观看视频 | 美女福利国产在线| freevideosex欧美| 老女人水多毛片| 日本爱情动作片www.在线观看| 亚洲国产精品一区二区三区在线| 亚洲人成网站在线播| 狂野欧美激情性xxxx在线观看| 国产精品久久久久久久电影| 欧美成人精品欧美一级黄| 国国产精品蜜臀av免费| 人体艺术视频欧美日本| 国产一级毛片在线| 2018国产大陆天天弄谢| 免费高清在线观看日韩| 建设人人有责人人尽责人人享有的| 黑人高潮一二区| 女人久久www免费人成看片| 日韩一区二区三区影片| xxx大片免费视频| 久久久久久久久久久免费av| 韩国高清视频一区二区三区| 一级片'在线观看视频| 免费高清在线观看日韩| 免费看av在线观看网站| 男女边吃奶边做爰视频| 国产精品久久久久久久电影| 女的被弄到高潮叫床怎么办| 狂野欧美激情性xxxx在线观看| 欧美xxⅹ黑人| 精品99又大又爽又粗少妇毛片| 久久久久人妻精品一区果冻| 男女免费视频国产| 乱人伦中国视频| 校园人妻丝袜中文字幕| 一级,二级,三级黄色视频| 少妇精品久久久久久久| 国产成人a∨麻豆精品| 成人手机av| 久久狼人影院| 性色avwww在线观看| av福利片在线| 免费看不卡的av| 亚洲精品日本国产第一区|