Nuclear gene phylogeography reveals the historical legacy of an ancient inland sea on lineages of the western pond turtle,Emys marmorata in California

The historical biogeography of California’s taxa has been the focus of extensive research effort. The western pond turtle (Emys marmorata) is an example of a wide‐ranging taxon that spans several well‐known California diversity hotspots. Using a dataset comprised of one mitochondrial and five nuclear loci, we elucidate the major biogeographic patterns of the western pond turtle across the California landscape. By employing a combination of phylogenetic and network‐based approaches, we recovered a relatively ancient (c. 2–8 Ma) north/south split among populations of E. marmorata and find an area of intergradation centred in the Central Coast Ranges of California. In addition, discordant mitochondrial/nuclear genetic patterns suggest subsequent gene flow from northern populations and from San Joaquin Valley populations into the Central Coast Ranges after the Pliocene‐Pleistocene marine embayment of the Great Central Valley subsided. Our results emphasize the utility of nuclear DNA phylogeography for recovering the impact of relatively ancient biogeographic events, and suggest that the Central Coast Ranges of California have played a major role in the geographic structuring of the western pond turtle, and possibly other co‐distributed taxa.     

Field observation of predation on a turtle by a giant water bug

The giant water bug, subfamily Lethocerinae, which has the largest body size among Belostomatidae, is known to be a vertebrate specialist that preys upon fish, amphibians and snakes. However, there have been no reports concerning predation on a turtle by Lethocerinae. Here, I report that a male giant water bug Kirkaldyia (Lethocerus) deyrolli (Heteroptera: Belostomatidae) (58.09 mm in total length) was catching hold of a turtle Chinemys reevesii (34.14 mm in carapace length) in a ditch adjoining a paddy rice field. This is a first report of K. deyrolli eating a turtle.     

短时高温暴露对菊方翅网蝽成虫存活和生殖特性的影响

为了明确短时高温暴露对菊方翅网蝽成虫存活和生殖特性的影响,将采集的菊方翅网蝽成虫辨别雌、雄后放入玻璃管中,然后将其放入水浴进行短时高温暴露,实验设置了6个温度,分别为35℃、37℃、39℃、41℃、43℃和45℃,暴露时间为2 h,随后将其在26℃下恢复2 h后研究其存活率、寿命、产卵前期、产卵期、产卵量及F_1代存活能力和性比的变化。以饲养在26℃未经高温暴露的菊方翅网蝽为对照。结果表明,在35～39℃范围内,高温暴露2 h对菊方翅网蝽成虫的存活、寿命、产卵期、产卵量、F_1代性比没有影响,但会导致其产卵前期、F_1代卵孵化率和存活率显著延长或下降。41℃下暴露2 h,除了菊方翅网蝽雌虫的存活率与对照没有显著差异外,雄虫的存活率、雌虫的繁殖能力以及后代的存活能力均出现显著下降;菊方翅网蝽成虫在43℃下暴露2 h,其雌雄虫的存活时间均不超过24 h。45℃下暴露2 h,其雌雄虫的存活时间不超过2 h。因此,41℃及其以上的短时高温暴露对菊方翅网蝽的种群发展具有一定的威胁。     

温度对黄喉拟水龟性别决定的影响

研究了不同孵育温度对黄喉拟水龟(MauremysmuticaCantor)性别决定的影响,同时分析了孵育温度对胚胎发育及成活率的影响。实验设置的3个孵化温度为(25±0.5)℃,(29±0.5)℃和(33±0.5)℃。每一温度指标下设置40枚受精卵。在实验温度内,胚胎的发育速度随着孵化温度的升高而加快,所用的孵育时间也越来越短。孵化累积温度CTUs在25℃时最高,在29℃时最低,而33℃时则居中,在25℃和29℃时,孵化成活率较高,均达到97.5%。在33℃时孵化成活率只有67.5%,而在孵出的稚龟中亦有一定数量的畸形龟,累积孵化温度也高于29℃时的CTUs,说明33℃的孵育温度对胚胎发育有不利影响,预示33℃已临近其胚胎发育的存活阈(Survivalthreshold)。在25℃时,雄性子代占优势,雌性率为23.7%;在33℃时,雌性子代占绝对优势,雌性率为94.7%;在29℃时,性比达到平衡,雌性率为50%。经X2检验,在25℃及33℃时的性比与依赖概率估计的性比(1∶1)有极显著的差异(p<0.005),这种显著的偏离说明黄喉拟水龟的性别决定属于TSD机制,而且可能属于其中的TSDⅠ型,即高温产生雌性子代,低温产生雄性子代。而29℃可能是黄喉拟水龟性别决定的临界温度。     

黄喉拟水龟转铁蛋白基因的克隆以及表达特征分析

转铁蛋白在铁的新陈代谢中起着重要的作用,参与细菌感染后的免疫反应。研究克隆了黄喉拟水龟Tf基因组DNA全长序列,并对Tf基因的序列特征进行了分析。序列分析表明,黄喉拟水龟Tf是由两个相似结构域构成的单一肽链,每个结构域包含两个亚基,它们相互作用形成一个深的、亲水的铁结合位点。其基因组DNA由17个外显子和16个内含子组成,与其他脊椎动物Tf基因结构相似,显示了黄喉拟水龟Tf基因在结构上的保守性。同源性分析表明,黄喉拟水龟的Tf基因与鸟类、爬行类的Tf基因同源性最高,约为75%—97%;与哺乳类Tf基因的同源性约为65%—75%;与爪蟾等两栖类的Tf基因也有一定的同源性。荧光定量PCR结果显示,黄喉拟水龟人工感染粘质沙雷氏菌后,Tf基因在其肝脏、脾脏、肾脏及心脏各组织中的表达量均有上调的趋势,这与其他动物经病原刺激后的表达特征具有相似性。     

乌龟线粒体全基因组序列和结构分析

龟鳖类同其它类群脊椎动物的系统进化关系一直存在争论。为进一步从分子水平上探讨这一问题,本文参照近源物种的线粒体基因组,设计了16对特异引物,采用PCR产物直接测序法测得了乌龟线粒体基因组全序列。结果表明:乌龟线粒体基因组序列全长16576bp,包括2个rRNA基因、22个tRNA基因、13个蛋白质编码基因和1个非编码控制区。乌龟线粒体基因组结构和基因排列顺序与其它龟鳖类相同,在“WANCY区”包含一个“stemloop”结构,ND3基因174位点存在一个额外插入的腺苷酸(A)。本文通过比较分析结构基因在主要脊椎动物类群中的排列顺序,探讨了龟鳖类与其它主要脊椎动物类群的系统进化关系     

莲-鳖-龟-鱼生态种养模式对莲田病虫害的影响

设置莲-鳖-龟-鱼生态种养（JGBY）、莲-龟-鱼生态种养（JGY）、子莲单作（JCK）及子莲生态种植（JCK0）田间对比试验;研究不同种养模式对莲田病虫害的影响。结果表明:投放养殖动物后;与JCK0相比;在各处理间发病率差异最大的时期;JGBY、JGY、JCK对莲褐纹病的防效分别为21.3%、20.8%和42.5%;对莲叶枯病的防效分别为17.7%、16.4%和37.6%;对莲腐败病的防效分别为7.7%、6.4%和27.5%;JGBY处理对各主要病害的防效比JGY更好;但防控效果均不如JCK处理。在各虫害高峰期;各处理对食根金花虫和福寿螺的控制效果最好;JGBY、JGY和JCK处理的食根金花虫的虫口密度较JCK0分别下降76.9%、46.2%和84.6%;福寿螺的虫口密度分别下降69.2%、53.8%和46.2%;各处理对食根金花虫和福寿螺的防效分别表现为:JGY相似文献   

How do goannas find sea turtle nests?

Squamate reptiles rely heavily on visual and chemical cues to detect their prey, so we expected yellow‐spotted goannas (Varanus panoptes) which are predators of sea turtle nests on mainland beaches in northern Australia would use these cues to find sea turtle nests. Ghost crabs (Ocypode ceratophthalmus and Ocypode cordimanus) are also common on Australian sea turtle nesting beaches and frequently burrow into sea turtle nests. However, the potential for ghost crab burrowing activity at sea turtle nests to signal the location of a nest to goannas has not been investigated. Here, we used camera traps and presence of tracks at nests to record goanna activity around selected nests during the incubation period and 10 days after hatchling turtles emerged from their nests. We also recorded the number of ghost crab burrows around nests to evaluate ghost crab activity. Our results indicated that nest discovery by goannas was independent of nest age, but that the nest visitation rate of goannas and crabs increased significantly after a nest had been opened by a goanna or after hatchlings had emerged from the nest. There was no apparent connection between ghost crab burrows into a nest and the likelihood of that nest being predated by goannas.