雷山髭蟾繁殖生态初步研究

2014年10月—2016年6月,采用野外定点观察的方法系统观察雷山髭蟾Vibrissaphora leishanensis的繁殖生态习性。研究表明:雷山髭蟾求偶、交配、产卵均在水体中进行;繁殖期在每年的9月底至12月底,11月中旬最集中;雄性的体长和体质量均显著大于雌性;繁殖行为包括筑"巢"、鸣叫求偶、抱对、产卵,雄蟾单个鸣叫,抱对时雄蟾主动。有共用一个"巢"穴抱对产卵的习性和集群产卵的行为。卵群直径65.13~100.47 mm,平均77.73 mm±9.47 mm(n=54);窝卵数162~394粒,平均226.79粒±7.89粒(n=54);卵径2.06~5.18 mm,平均3.82 mm±0.91 mm(n=270);孵化期为107~157 d,平均127.71 d±7.38 d(n=54)。     

瑶山髭蟾生态习性的研究

瑶山髭蟾主要分布在广西大瑶山海拔1000—1500米的山冲溪流附近,其生态环境是植被丰富、水源充足、气候温湿的常绿阔叶林带。全年大部分时间都栖息在陆地阴暗处的土壤及洞穴内。主要以植物和小昆虫为食。繁殖期在每年12月“大雪”之后到“冬至”前后,产卵期很短,仅在“冬至”前后10天内进行,雌雄抱对产卵一般都在黎明前完成,属一次性产卵类型,卵群粘附在石块底部的凹陷处,每次产卵298—342粒,卵径3.8—4毫米。它们除在冬季繁殖外,而且在10℃的气温条件下,仍照常活动,因此,可能没有“冬眠”习性或“冬眠”期极短。     

雷山髭蟾卵团自然状态下发育观察初报

2007年11月至2008年4月在贵州雷公山自然保护区对雷山髭蟾卵团的自然发育进行了观察.研究区域位于海拔1500～1600 m的中山地带.雷山髭蟾11月中旬在森林溪流水中交配产卵,共发现6个产卵场和23个卵团.参照赵尔宓的蛙类胚胎及蝌蚪发育分期,将雷山髭蟾卵团发育分为3个阶段.早期发育阶段,从产下卵到原肠胚晚期,此阶段肉眼不能辨别卵粒变化情况;中期发育阶段,即神经板期到鳃血循环期,肉眼能识别出卵粒变化;晚期发育阶段,即角膜透明期到蝌蚪下水自由游泳.观察结果表明:未受到冰雪冻凝卵团早期发育平均为60 d,中期74 d,晚期12 d,总计146 d.受到雪灾冻凝的卵团早期发育平均为109 d,中期22 d,晚期13 d,总计144 d.经t检验,非冻凝的卵团和冻凝的卵团在早期和中期发育时间存在极显著差异,而晚期和总的发育时间无差异,说明雷山髭蟾胚胎早期发育若因外界不利因素延迟,会在后期自动调节发育速度,加快发育.     

自然环境下雷山髭蟾卵群发育观察

2015年10月至2016年4月期间,在雷公山保护区内的雷公山工区对雷山髭蟾(Vibrissaphora leishanensis)在野外自然环境下卵群发育进行了观察。共发现产卵场14个,卵群54团。雷山髭蟾卵群从受精卵发育到鳃盖褶期的平均时间为(127.71±1.38)d(107~157 d,n=54),产卵场的气温、水温和水深对胚胎发育有一定影响。     

峨眉髭蟾早期胚胎发育的初步观察

峨眉髭蟾(Vibrissaphora boringii Liu)的外部形态,刘承钊等(1945,1950,1961)曾有记载;有关该蟾的生物学和生态学方面的资料,费梁等(1984)也作过报道,并对分布于四川峨眉山和贵州梵净山两地的成蟾和蝌蚪的形态特征进行了比较,这些资料有助于了解我国特有的珍贵蛙类——峨眉髭蟾的概况。但是,有关峨眉髭蟾的胚胎发育资料尚未见有报道。1982年我们曾对峨眉髭蟾的近缘种雷山髭蟾(Vi     

瑶山髭蟾的核型

髭蟾是我国特有的无尾两栖类,主要分布在川、黔、滇、桂、浙、闽等省的山区。自刘承钊于1945年建立髭蟾属(Vibrissaphora Liu)以来,已先后发表有五种,即峨嵋髭蟾(Vibrissaphora boringii Liu),崇安髭蟾(V.liui Pope),雷山髭蟾(V.leishanensis Liu et Hu),瑶山髭蟾(V.yaoshanensis Liu et Hu)和哀牢髭蟾(V.ailaomica Yang,Chen et Ma)。赵尔宓、吴贯夫(1983,1987)报道了全部髭蟾种的核型,并提出了瑶山髭     

探访哀牢髭蟾

髭蟾在我国有5种。实事求是地讲,以前我对髭蟾一无所知,我相信一般人对它们也缺乏了解。在5种髭蟾中,有一种直到1984年才被发现,那就是哀牢髭蟾。哀牢髭蟾仅分布于云南滇中哀牢山和无量山地区,无量山国家级自然保护区是该物种分布的最北端。哀牢髭蟾的模式产地在云南景东徐家坝,哀牢山是科学家们首次发现它的地方,哀     

长“胡子”的蛙

风景秀丽的福建武夷山自然保护区,栖息着一种世界珍奇的“头上长角”的蛙类,当地社员称它为“角怪”,学名叫“崇安髭蟾”。长“胡子”的蛙 1925年和1926年夏天,美国纽约自然博物馆两栖、爬行类学者波普,两次来保护区崇安县西南的挂墩,采集蛙类和蛇类标本。1931年,波普在发表的关于福建两栖动物的文章中,将“角怪”作为角蟾(与髭蟾近似的一类蛙)的一种。髭蟾属两栖纲、锄足蟾科,体长7—9厘米,头部、躯干部和四肢背面,均呈蓝褐色或青灰色,体侧和背上有不规则的斑点,腹面呈紫红     

峨眉髭蟾在重庆的分布——蝌蚪在无尾类分类和多样性调查中的应用一例

2008年5月在重庆市酉阳县采集到7号体尾背部具有"Y"形斑纹的蝌蚪,对其形态特征和口部结构予以描述,经与峨眉髭蟾Vibrissaphora boringii和崇安髭蟾瑶山亚种V. liui yaoshanensis蝌蚪比较,确定其为峨眉髭蟾,为重庆市新纪录.现作为应用蝌蚪进行无尾两栖动物分类鉴定和多样性调查实例予以报道.     

奇妙的动物王国

崇安髭蟾崇安髭蟾的背面红棕色,不规则散布着无数深色小点,四肢背面有深色横斑,腹面色较浅淡。繁殖季节里,雄蟾上唇缘近口角处两侧各有1～2枚黑色锥状角质刺。崇安髭蟾为我国特有种,见于福建、江西、广     

Phylogenetic relationships of the mustache toads inferred from mtDNA sequences

Species of the genus Vibrissaphora are unique among all anurans in that males exhibit external cornified spines in the maxillary region during the breeding season. They were separated from species of the genus Leptobrachium based on this unique character. We construct a phylogeny using the 16S, ND4, and cytochrome b mitochondrial genes of 42 individuals from eight species of Vibrissaphora and five species of Leptobrachium from mainland China, Southeast Asia, and Hainan Island. Species of both Oreolalax and Scutiger were used as outgroups. The results indicate that: L. huashen and L. chapaense form a clade that is nested within Vibrissaphora, and L. hainanense is the sister taxon to the clade comprising all Vibrissaphora plus L. chapaense and L. huashen; V. boringiae is grouped with a clade consisting of V. leishanensis, V. liui, and V. yaoshanensis; and V. yaoshanensis is a species separate from V. liui. We propose taxonomic changes that reflect these findings. Also based on the resulting phylogenetic trees, we propose that the mustache toads originated in the trans-Himalayan region of southwest China, and that the evolution of maxillary spines, large body size, and reverse sexual size dimorphism in these frogs was influenced by intrasexual selection due to adopting a resource-defense polygyny mating system.     

两种髭蟾的Ag—NORs,C—带及核型的研究

本文叙述和比较了峨眉髭蟾和哀牢髭蟾的核型,C-带和Ag-NORs,结果表明两者有下列相同方面:2n=26(6+7)、除No.3为SM外,其余诸对概为M,次缢痕和Ag-NoRs位于6q,并都表现出异形现象,No.1长臂有长度异形,但所增染色体片断不呈现C-带正染,C-带正染主要是在各对染色体的着丝点区域,另外No.2短臂近着丝区域亦为正染。这些表明二者之间有很大的核带型同源性。但是二者间在核型的某些对应染色体之间,在相对长度(6对)和臂比值(2对)方面有显著性差异,故可推测其机制是相互易位和臂间倒位。另外,哀牢髭蟾未发现与性别相关的异形性染色体。     

The influence of temperature and spatial distribution on the susceptibility of southern leopard frog eggs to disease

Since host defenses to infectious disease are often costly, one would expect hosts to use their defenses only when the threat of infection is high. Southern leopard frogs (Rana sphenocephala) at Ellenton Bay in South Carolina (USA) have an extended breeding season and their eggs are exposed to a wide range of temperatures depending on the time of year when they are laid. Adults aggregate their egg masses in cold temperatures, but separate them in warm temperatures. The spatial aggregation of egg masses may insulate eggs from cold temperatures, but may also affect the transmission of pathogens between the eggs. I examined the effects of temperature, pathogens, and spatial distribution on the survival of R. sphenocephala in the egg stage. Field observations found that temperature had little effect on the number of infected eggs within egg masses, but that egg masses in colder water were more likely to be aggregated together. In a controlled laboratory experiment, the presence of aquatic oomycetes led to higher mortality in cold temperatures than they did at warmer temperatures. Infectious disease may be a selective force that favors R. sphenocephala adults that aggregate their offspring when the threat of disease is high. Host aggregation can reduce the risk of infection when pathogens have a slow generation time that hinders them from responding to an abundance of hosts.     

Oviposition deterrents of Callosobruchus maculatus (Coleoptera: Bruchidae)

Abstract Many bruchids distribute their eggs uniformly among the host seeds available to them and tend to avoid adding eggs to seeds bearing any eggs if pristine seeds remain. Several authors have postulated that the adult cowpea seed beetles, Callosobruchus maculatus (F.) (Coleoptera: Bruchidae), produce pheromones inhibiting oviposition by females exposed to them. It is shown that both sexes produce compounds which can be washed from glass surfaces in a variety of organic solvents which do not deter oviposition as such, but seeds coated with such washings are avoided by ovipositing females when they are selecting seeds for egg-laying and uncoated seeds are available. Some components, at least, of the products persist for at least 30 days, longer than the normal development time of insects in the seeds. The compounds affect the distribution of eggs among the available seeds. At least three different biotypes of the species produce, recognize, and respond in the same way to each other's products. It is emphasized that the eggs themselves may not be the site of the product produced by females but that the physical presence of eggs cannot be overlooked in any discussion of the possible role of pheromones in oviposition and egg distribution by bruchids.     

Oviposition decisions in an endoparasitoid under self-superparasitism conditions

Superparasitism is a widespread phenomenon. Having accepted superparasitism, mated female parasitoids must decide on the sex of each egg they subsequently lay into the same host. Theory predicts that this decision is either based on host quality, when more male eggs are laid in hosts that are already parasitized because they are perceived to be of poorer quality; or more eggs are laid of the sex that is most likely to be a strong larval competitor, i.e. generally females.Anastatus disparis is a facultative endoparasitic egg parasitoid. We used ‘artificial’ hosts to explore outcomes of decision making by A. disparis during superparasitism under a manipulated absence of larval competition. When only one egg was laid it was always female. As the number of eggs laid increased, so more of them were male. This supports the theory that oviposition decisions are based on host quality; more male eggs were laid in hosts that were already parasitized and thus of poorer quality.In a second experiment, eggs were exposed to parasitoids for different periods of time. Half the eggs were dissected to determine the number of parasitoid eggs that had been laid. The remaining eggs were incubated and the number and sex of offspring that ultimately emerged, following larval competition, were recorded. Under superparasitism conditions fierce larval competition ensued; only one offspring survived and they were predominantly female.In conclusion, oviposition decisions by female A. disparis accepting self-superparasitism were made based on host quality.     

湖南通道发现雷山琴蛙

2020年5月23日在湖南省通道县万佛山镇(26° 11′47″N,109°56′21″E,海拔924 m)采集到4号两栖动物标本,经形态特征比较,与雷山琴蛙(Nidirana leishanensis)相似;基于线粒体16S rRNA构建的琴蛙属(Nidirana)部分物种贝叶斯系统发育树显示,此次采集的琴蛙标本与雷...     

A phylogenetic analysis of the frog genera Vibrissaphora and Leptobrachium, and the correlated evolution of nuptial spine and reversed sexual size dimorphism

A phylogeny of the frog genus Vibrissaphora and seven Leptobrachium species was reconstructed based on 3808 base pairs of mitochondrial and nuclear DNA sequence data. Maximum parsimony, Bayesian, and statistical parsimony approaches were employed to reveal the historical relationships among the recovered haplotypes. The species of the genera Vibrissaphora and Leptobrachium failed to form their respective monophyletic groups. Therefore, Vibrissaphora should be part of the genus Leptobrachium. Our analysis also further delineated several species boundaries; Leptobrachium chapense is not a single species, rather, a species complex. On the other hand, although L. liui demonstrated substantial morphological variation, all populations belong to one species. The RAG-1 data revealed a case of species-level non-monophyly; when studying slowly evolving genes, population coalescence may not have been reached within species. The phylogenetic comparative analysis revealed a positive correlation between evolution of male nuptial spines and reversed sexual size dimorphism in this group. Resource defense polygyny and male parental care are possible explanations for the presence of large male size.     

Identification of a sperm receptor on the surface of the eggs of the sea urchin Arbacia punctulata

The possibility that the surface of the egg of the sea urchin Arbacia punctulata contains a species-specific receptor for sperm has been investigated. The extent of fertilization of eggs of A. punctulata, which is proportional to the number of sperm, is unaffected by the presence of either eggs or membranes prepared from eggs of Strongylocentrotus purpuratus. In marked contrast, membranes prepared from eggs of A. punctulata quantitatively inhibit fertilization of A. punctulata eggs by A. punctulata sperm. Several lines of evidence indicate that this inhibition is due to the presence of a membrane-associated glycoprotein that binds to the sperm, thus preventing them from interacting with receptor on the surface of the eggs. First, eggs treated with trypsin are incapable of being fertilized, although they can be activated with the Ca2+ ionophore A23187. Moreover, membranes prepared from eggs pretreated with trypsin do not inhibit fertilization of eggs. Second, receptor isolated in soluble form from surface membranes binds to sperm and thus prevents them from fertilizing eggs; the inhibition by soluble receptor is species-specific. Third, the soluble receptor binds to concanavalin A-Sepharose. Fourth, eggs are incapable of being fertilized if they are pretreated with concanavalin A. The specificity of inhibition, and the affect of trypsin and concanavalin A on intact eggs, suggest that the receptor is a species-specific macromolecule located on the surface of the eggs. The sensitivity of the receptor to trypsin, and its ability to bind to concanavalin A, indicate that it is a glycoprotein.     

THE TIMING OF BIRDS' BREEDING SEASONS

Examination of survival rdtes of nestlings and fledglings of some species show that there is a strong tendency for those young which are hatched earliest in the season to have the greatest chance of surviving to breed. Since natural selection so strongly favours parents who leave many surviving young, the question arises as to why other birds breed later than the date at which they could most successfully raise their young.
It is suggested that the food supply for the breeding females immediately prior to the breeding season may limit their ability to form eggs and the females may thus not be able to lay at the time which would result in young being in the nest at the best time for raising them, but as soon after this time as the female is able to produce her eggs. Not all species are likely to be prevented, by food shortage, from breeding at the best time for raising young and the groups of birds most likely to be affected are discussed.