棘腹蛙生物学特性及资源保护研究进展

棘腹蛙(Quasipaaboulengeri)是无尾目(Anura)叉舌蛙科(Dicroglossidae)棘胸蛙属的两栖动物。因其以农业和森林害虫为食且对生存环境要求高的特点,故有保护和监测环境的生态功能。但由于生态环境恶化和过度捕捉等原因,造成野生棘腹蛙数量急剧下降,被《中国脊椎动物红色名录》列为易危种。本文从棘腹蛙的习性、生存环境特征、系统进化、人工养殖和资源保护等方面进行了综述,为进一步研究棘腹蛙提供基础资料和理论依据。     

棘胸蛙的性腺分化及温度对其性别决定的影响

单性养殖在棘胸蛙(Quasipaa spinosa)养殖中意义显著。为了了解棘胸蛙性腺分化,并探讨在不同的培育温度条件下性腺分化的差异。通过组织切片观察了棘胸蛙原始性腺的形成和性腺分化。棘胸蛙的性腺分化有其特殊性:生殖嵴形成时,其中既有体细胞,又有原始生殖细胞(PGCs);无论原始性腺是分化成为精巢还是卵巢,其中都出现一个带有单层扁平上皮初生性腔,当单层扁平上皮逐渐消失后形成次生性腔。性腔周围的PGCs开始长大2—3倍时,性腺将分化成为卵巢;体细胞渗入性腔中,使腔隙变小直至消失,这种原始性腺分化成为精巢。棘胸蛙蝌蚪孵化后的l7—80 d(Gosner 25—26期)为性腺分化的敏感时期。实验选取同一批次刚孵出蝌蚪(Gosner 24期),分别用不同水温(16±1)℃、(27±1)℃、(31±1)℃3组实验组及自然水温(23±1)℃对照组条件下的培育蝌蚪。结果显示,对照组的雌、雄性比为26∶24,雄性率接近50%;(16±1)℃实验组的雌、雄比例为33∶17,雄性率仅34%(P0.05);从(27±1)℃实验组起,雄性率提高,(31±1)℃实验组的雄性率达70%(P0.05)。棘胸蛙的性别分化属于温度依赖型性决定(TSD)。较高的培育温度可使棘胸蛙蝌蚪性别分化趋向雄性,而较低的培育温度则使蝌蚪雌性化。     

贵州省首次发现合江棘蛙

2010年7和8月,采用样带法于贵州省习水国家级自然保护区进行两栖动物资源调查,在三叉河片区(28°30′43.67″N,106°25′03.72″E,海拔1 087 m)采集到25只形态相似的两栖动物标本,经过鉴定,该标本为无尾目(Anura)叉舌蛙科(Dicroglossidae)棘胸蛙属(Quasipaa)的合江棘蛙(Q.robertingeri),系贵州省两栖动物新纪录。标本现保存于贵阳学院生态研究中心标本室。     

Commensalism between cichlid fishes through differential tolerance of guarding parents toward intruders

In the shallow waters of Lake Tanganyika, a benthic cichlid Xenotilapia boulengeri rests in a cluster around the nesting sites of substrate-brooding cichlids Lepidiolamprologus attenuatus and L. elongatus . Experimental removal of parent Lepidiolamprologus guarding free-swimming young drastically reduced the number of X. boulengeri around these nesting sites within a few days, suggesting that their presence has a positive effect on attracting X. boulengeri . Xenotilapia boulengeri were less frequently disturbed by the scale-eating cichlids Perissodus microlepis and Plecodus straeleni when they remained near nesting sites of these species than when stayed away. This was attributed to the territorial behaviour of guarding parents who drove away scale-eaters at greater distances, while allowing X. boulengeri , harmless to their young, to approach the nesting site. It is concluded that a clumped distribution of X. boulengeri results from differential tolerance of breeding parents toward intruders that produces a safety zone from scale-eaters.     

湖南壶瓶山国家级自然保护区棘腹蛙种群初探

2004年5～10月,在湖南壶瓶山国家级自然保护区,采用标志-重捕法对棘腹蛙种群进行了初步的研究.结果发现,棘腹蛙种群在一年之内的种群变化呈“∧”形,即从出蛰到繁殖高峰期呈上升趋势;高峰期后由于气温、人类的捕捉、洪水等的影响呈下降趋势,同时分析了种群数与海拔、生境等因素的关系.     

Structure and projected decline of a Karoo dwarf tortoise population

Inconspicuous, secretive, or sparsely distributed species receive relatively little research attention, potentially leading to uncertainty about their status and lack of efforts to conserve them. Karoo dwarf tortoises (Chersobius boulengeri) are endemic to South Africa, spend most of the time in retreats at remote arid locations, and are seldom seen. We conducted a 3-year (2018–2020) mark-recapture study to investigate the size and structure of the only Karoo dwarf tortoise population currently known to exist. The population in the 16-ha core of our study site consisted primarily of adult males and females, at a density of 3.3 individuals/ha. Many individuals had severely worn shells and appeared old. Small individuals (straight carapace length <65 mm) represented just 8% of the population and were mostly recent hatchlings. Overall, tortoises had high estimated survival rates (0.77–0.95; lower 95% confidence limit for the smallest tortoises was 0.16), despite a 15-month drought. The lack of small individuals may reflect low levels of recruitment and population decline. Predation by corvids was an obvious threat to all size classes. We estimated that the local population across the 250-ha study area was 800–900 males and females, and recommend precautionary conservation measures focused on reducing human-subsidized avian predation.     

Rivers as barriers for high elevation amphibians: a phylogeographic analysis of the alpine stream frog of the Hengduan Mountains

At high altitude, rivers may function as barriers for amphibians. We examined 21 populations of Scutiger boulengeri from the Hengduan Mountains with 1038 base pairs of mitochondrial cytochrome b gene sequences. The haplotypes of S. boulengeri formed three clades on the gene tree, and each clade was restricted to one mountain ridge separated by two major river systems, the Yalong River and the Dadu River. The vicariant pattern of the gene tree suggests that these rivers functioned as effective barriers during population differentiation. On the other hand, mountain ridges may have facilitated amphibian movement. Populations within the uninterrupted mountain ranges of clades II and III, revealed little genetic structure. The northern clade I, harboured a substantial amount of genetic variation, which might be the consequence of the rugged terrain and heterogeneous habitat of this area. Furthermore, one outgroup species, Scutiger glandulatus , formed the fourth clade and nested within S. boulengeri , suggesting that S. boulengeri is likely a paraphyletic species or a species complex.     

棘腹蛙消化道脂肪酶的分布及pH和温度对脂肪酶活力的影响

采用聚乙烯醇橄榄油乳化液水解法,测定了棘腹蛙消化道不同部位的脂肪酶活力,研究了pH和温度对脂肪酶活力的影响。结果显示,棘腹蛙消化道不同部位脂肪酶活力依次为回肠>直肠>十二指肠>胃>食道。pH和温度显著影响脂肪酶的活力,二者对脂肪酶活力影响的关系曲线均呈现为单峰型,食道、胃和肠道脂肪酶活力的最适pH值分别为5.0、5.0和7.5,最适温度均为35℃。     

棘胸蛙（Quasipaa spinosa）对重复急性冷暴露的生理应激与适应耐受

为探讨棘胸蛙(Quasipaa spinosa)这一溪源性两栖类对环境温度极端变化做出的生理响应与适应机制,测定了该物种在反复遭受急性冷暴露(4℃,12 h)过程中其非特异性免疫反应、氧化还原状态以及热休克蛋白70(Hsp70)mRNA表达的变化,结果发现:棘胸蛙在初次冷暴露过程中外周血细胞吞噬活性(第4小时和第12小时;P0.05)、脾巨噬细胞呼吸爆发强度(第4小时和第12小时;P0.05)以及胃溶菌酶活力受到显著抑制(第12小时;P0.05);当蛙返回到22℃环境12 h后3种免疫指标均恢复到初始和对照组水平(P0.05)。经过连续7 d冷暴露后,除溶菌酶外,血细胞吞噬活性和脾巨噬细胞呼吸爆发强度均能恢复到初始和对照组水平(P0.05)。另外,冷暴露增加了肝脏和肾脏内丙二醛(MDA)的含量,但肾脏内MDA含量升高的幅度要明显大于肝脏;肝脏SOD活力和GSH含量也表现出急性和适应性升高,而肾脏仅SOD活力有所升高,暗示在低温胁迫状态下棘胸蛙肝脏氧自由基清除能力要强于肾脏。HSP70作为应激保护蛋白,当机体遭受冷暴露后肝脏Hsp70 mRNA表达量始终未呈现出应激性升高,反而受到显著抑制(P0.05)。综上所述,棘胸蛙在经历多次急性冷胁迫后体内部分非特异性免疫功能以及肝脏氧化防御系统可以产生不同程度的适应性改变。     

棘腹蛙肌肉嫩度及营养成分的初步分析

本文对棘腹蛙与牛蛙的肌肉嫩度作了比较,并测定了棘腹蛙肌肉的营养成分,且与甲鱼和田鸡的相应成分作了对照分析。结果表明,棘腹蛙肉质细嫩、营养价值高、风味较好,具有开发养殖前景。