Effects of Predation by Invasive Western Mosquitofish(Gambusia affinis) on Survival of Eggs,Embryos and Tadpoles of Pelophylax nigromaculatus and Duttaphrynus melanostictus in South China

Alien species are one of the most serious threats to the decline and extinction of native amphibian populations. In this study, we examined the predation of invasive Western Mosquitofish Gambusia affinis on the eggs, embryos, and tadpoles of Duttaphrynus melanostictus and Pelophylax nigromaculatus in south China. Our results suggested that the survival of eggs and embryos remaining in the egg capsules of P. nigromaculatus and D. melanostictus was significantly higher than those removed from the egg capsule at 12-h intervals within 72 h in the presence of G. affinis. The survival of P. nigromaculatus eggs and embryos without egg capsules was significantly lower than those of D. melanostictus without egg capsules. The survival of P. nigromaculatus eggs and embryos with egg capsules was significantly higher than those of D. melanostictus with egg capsules from 24 h to 72 h except for 12 h. The survival of D. melanostictus tadpoles was significantly higher than that of P. nigromaculatus tadpoles in the presence of G. affinis. The survival of Gosner stage 26 tadpoles of P. nigromaculatus was significantly higher than that of Gosner stage 30 tadpoles from 12 h to 60 h, but there were no significant differences at 72 h. In contrast, the survival of Gosner stage 26 tadpoles of D. melanostictus was significantly lower than that of Gosner stage 30 tadpoles within 72 h, recording every 12 h. The increasing temperature caused a significant increase in predation by G. affinis on P. nigromaculatus eggs and embryos. The outer jelly capsule surrounding anurans eggs might serve as a mechanical defense against predation by G. affinis due to its large diameter, relatively stationary state and unpalatability. The differences in the vulnerability of P. nigromaculatus and D. melanostictus embryos and tadpoles to G. affinis probably due to differences in the unpalatability, black skin and activity. Based on the magnitude of predation by G. affinis on the eggs, embryos and tadpoles of these two species and the combined impact of temperature, we might speculate that invasive G. affinis and global warming would have more detrimental impacts on population viability of P. nigromaculatus than D. melanostictus in China.

Antipredator Behavioral Responses of Native and Exotic Tadpoles to Novel Predator

Factors related to the invasion process, such as high abundance of invaders, residence time, and functional distinctiveness, are well documented, but less attention has been given to the effects of antipredator strategy of invasive species during colonization. In this study, we explored the antipredator strategy of an introduced species by comparing the predator avoidance behaviors of two native anuran species and one introduced （“exotic”） species in the presence of different predators. The two native anuran species used in the study were Black-spotted Pond FrogRana nigromaculata and Terrestrial Frog Rana limnocharis. The introduced （invasive） species used was American bullfrogLithobates catesbeianus. Chinese pond turtleChinemys reevesii, Red-backed rat snakeElaphe rufodorsata, and Big-headed turtle Platysternon megacephalum were used as predator species. Chinese pond turtles and Red-backed rat snakes are native predators of Black-spotted Pond Frogs and Terrestrial Frogs, while Big-headed turtles are novel （“unfamiliar”） to the two frogs. All three predator species are novel （“unfamiliar”） to the American bullfrog. The results show that tadpoles of the two native species displayed behaviors of recognizing the two native predators, but did not display the capability of identifying the novel predator. Results from our study also suggest that American bullfrog tadpoles exhibited strong antipredator behavioral responses by displaying the capability of identifying “unfamiliar” predators without cohabitation history and prior exposure to them. Such antipredator behavioral responses could have resulted in more favorable outcomes for an invading species during the invasive introductory process.

Effects of hydroperiod duration on developmental plasticity in tiger frog （Hoplobatrachus chinensis） tadpoles

While developmental plasticity can facilitate evolutionary diversification of organisms, the effects of water levels as an environmental pressure on tiger frogs remains unclear. This study clarifies the relationship by studying the responses of tiger frog （Hoplobatrachus chinensis） tadpoles to simulated hydroperiods （i.e., constant low water levels, constant high water levels, increasing water levels, decreasing water levels, rapid changes in water levels and gradual fluctuations in water levels） in a laboratory setting. ANOVA analysis showed that none of the water level treatments had any significant effect on the total length, body mass, or developmental stages of H. chinensis tadpoles half way through development （11 days old）. Tadpoles raised in rapidly fluctuating water levels had protracted metamorphosis, whereas tadpoles raised under low and gradually fluctuating water levels had shortened metamorphosis. None of the water level treatments had a significant effect on the snout-vent length （SVL） or body mass of H. chinensis tadpoles at Gosner stage 42, or on the body mass of tadpoles at Gosner stage 45. However, the＇ tadpoles raised in high levels and rapidly fluctuating water levels, significantly larger SVL at Gosner stage 45, while ones under gradually fluctuating water levels had smaller SVL than the other groups. Time to metamorphosis was positively correlated with body size （SVL） at metamorphosis in H. chinensis tadpoles. H. chinensis tadpoles under constant low water level had the highest mortality rate among all the treatments （G-test）. Moreover, ANOVA and ACNOVA （with body length as the covariate） indicated that water levels had no significant effect on either the morphology （i.e. head length, head width, forelimb length, hindlimb length and body width） or the jumping ability of juvenile H. chinensis. These results suggest that the observed accelerated metamorphosis and high mortality of H. chinensis tadpoles under decreasing water level treatment was driven by density-induced physical interaetions among increasing conspeeifics.

Effects of light intensity on activity in four sympatric anuran tadpoles

Though light conditions are known to affect the development and anti-predation strategies of several aquatic species, relatively little is known about how different species react to light, or how light can affect these species during different points in their life-cycle. In this study, we used four sympatric anuran tadpoles （Bufo gargarizans, B. melanostictus, Pelophylax nigromaculatus and Microhyla fissipes） as animal system to examine species-specific activities of the underdoing different light intensity treatments, so as to better understand how they respond to light. We exposed four different species of tadpoles to 1660 and 14 lux light intensity treatments and then measured several parameters including development stage, body length and tail length, and as well as their basic activities. The results of this observation and analysis showed that the activities of tadpoles were significantly greater in B. gargarizans and B. melanostictus than in P. nigromaculatus and M. fissipes; and were also significantly greater during times of high light intensity as compared to during low light intensity. Moreover, the observed relationship between species and light intensity was significant. The activities ofB. gargarizans and B. melanostictus tadpoles were greater in high light, while the activity of P. nigromaculatus tadpoles was greater in low light intensity, while M. fissipes tadpoles showed no differences in either low or high intensity light. Furthermore, the activities orB. gargarizans, B. melanostictus and M. fissipes tadpoles in terms of developmental stage, body size or tail length did not seem to differ with light intensity, but during early larval developmental period of P. nigromaculatus, the activity of tadpoles was negatively correlated with development stage, but irrelevant to either body size or tail length in different light intensities. These results lead us to conclude the observed activities of the four sympatric anuran tadpoles are closely correlated with their specific anti-predation strategies.

Genotoxicity of Three Avermectins on Polypedates megacephalus Tadpoles Using the Comet Assay

Avermectins are a new class of macrocyclic lactones derived from mycelia of the soil actinomycete, and are used as effective agricultural pesticides and antiparasitic agents. However, run-off from crops treated with avermectins may contaminate various bodies of water, and accumulated to certain concentrations to impact the development of aquatic animals. Here, we tested the genotoxicity of three avermectins （abamectin, ABM; ivermectin, IVM; and emamectin benzoate, EMB） on Polypedates megacephalus tadpoles by the alkaline single-cell gel electrophoresis assay. Tadpoles were treated for 48 h in the laboratory with different concentrations of these three agents, 0.006, 0.012, 0.018, 0.024, 0.030 mg/L for ABM, 0.003, 0.006, 0.009, 0.012, 0.015 mg/L for IVM and 0.04, 0.06, 0.08, 0.10, 0.12 mg/L for EMB, and then measured their DNA damage by the Comet assay tail factor %. The concentrations of resulted in highly significant increases in DNA damage of the tadpoles were found above the concentration threshold of 0.012 mg/ L ABM, 0.003 mg/L IVM and 0.06 mg/L EMB and linear correlations between the intensity of DNA damage and the concentrations of these three avermectins. Our results showed clearly that avermectins caused dose dependent DNA damage on amphibian tadpoles, and there might be a control on the misuse of avermectins.

Morphology of Kaloula rugifera and K. borealis Tadpoles(Anura: Microhylidae: Kaloula verrucosa Group) in China

The external morphology and internal oral features of the tadpoles of Kaloula rugifera and K. borealis are described in this paper. Similarities between these two larvae include external morphology, oral disc, internal oral features(floor and roof), terminal mouth, lateral eyes, single midventral spiracle, absence of keratinized jaw sheaths and labial teeth, absence of lingual papillae and postnarial arena, while the body of K. rugifera is bigger than that of K. borealis at stages from 36 to 39 and the number of papillae in the buccal cavity is 12–19 and 9–16, respectively in the two species. All the similarities and differences of the two species illustrate that the tadpoles within the family Microhylidae could be attributed to assistance in clarifying a certain taxonomic treatment in Microhylidae.

Bioconcentration kinetics of PCBs in various parts of the lifecycle of the tadpoles Xenopus laevis

Polychlorinated biphenyls （PCBs） in Xenopus laevis have been reported only for a few congeners. Additionally, there is very little information on the ability of Xenopus laevis to bioconcentrate PCBs. To address these issues, the tadpole Xenopus laevis was exposed to Aroclor 1254 mixtures in water at room temperature for 110 d followed by an additional 110 d of nonspiked PCBs in the water for the control group. During the whole process, bioconcentration factors （BCFs） of PCBs ranged from 1180 to 15670. For most PCB congeners, the highest and lowest bioconcentrations of the kinetic curves were found to be remarkably simultaneous, respectively. All 141 PCB congeners under the same experimental conditions had no linear correlation on the lgBCF versus lgKow relationship. The relationship between lgBCFs and lgKow followed a parabolic pattern indicative of selective bioconcentration, suggesting that the kinetic curves of the PCB congeners observed in the lifecycle of the tadpoles may be concentrated due to the amphibian special species and internal metabolism. In contrast, lgBCFs for PCBs were inversely related to lgKow, suggesting that a metabolism of the higher Kow PCB congeners occurred. These results support the author＇s conclusion that the tadpole Xenopus laevis plays major roles in the bioconcentration of PCB congeners, and demonstrated that the exposure kinetic curves of PCB congeners are complex. Besides the amphibian metamorphous development, the lifecycle of the tadpole Xenopus laevis also may be of importance in determining the bioconcentration of PCB congeners.

The Influence of Environmental Factors on the Behavior and Mortality Risk of Polypedates megacephalus Tadpoles

Since tadpoles change their behavior when facing adverse environmental conditions, observing tadpoles in a tank can help detect problems in their ma intena nce. Detecting such a bnormal behavior early, an amphibian breeder can react quickly, by changing the conditions. If quick and appropriate, such a reaction can save unnecessary deaths. The paper presents an experimental study on the behavior of tadpoles of Polypedates megacephalus in various adverse environmental conditions. In addition to a control 25-liter tank, 5-liter tanks with 10 tadpoles each were studied, each having various improper conditions. Observations included the degree of tank exploration by the tadpoles, their mortality, anomalies in swimming behavior, and eating behavior.

Differentiations of 5-HT and GAS cells in the digestive canals of Rana chensinensis tadpoles

In the current study, 5-nydroxytryptamine （5-HT） and gastrin （GAS） cells in the digestive canals of Rana chensinensis tadpoles at different developmental stages were investigated by immunohistochemistry. Results showed that the 5-HT cells were only detected in the duodenum before metamorphosis began, and were extensively distributed in the stomach, duodenum, small intestine, and rectum thereafter, with the highest counts found in the duodenum and rectum when metamorphosis was completed. The GAS cells were only distributed in the stomach and duodenum, and only rarely detected in the duodenum before metamorphosis began, but increased in the stomach during metamorphosis and showed zonal distribution in the gastric mucosa when metamorphosis was completed. Metamorphosis is a critical period for amphibians, during which structural and functional physiological adaptations are required to transition from aquatic to terrestrial environments. During metamorphosis, the differentiations of 5-HT cells in the gastrointestinal canals of tadpoles could facilitate mucus secretion regulation, improve digestive canal lubrication, and help water- shortage food digestion in terrestrial environments. Conversely, GAS cell differentiations during metamorphosis might contribute to the digestive and absorptive function transition from herbivore to omnivore.

enriched diets and the growth, development and survival of litoria moorei (anura) tadpoles reared in captivity at low density

Increasing numbers of amphibian species require conservation breeding programs for their survival.A major challenge is the efficient rearing of tadpoles,many of which require complex habitats and specialised diets.Aquatic tadpoles of the West Australian frog Litoria moorei were kept at low density(1 tadpole per 1.95 litres water) in aquaria at 25℃.Fed on a staple diet of boiled lettuce and leaf litter,group of diets were supplemented with either control,Wardley Premium Spirulina Discs,Sera~(TM) GVG-mix tropical fish food,or a combination of Wardley Premium Spirulina discs and Sera~(TM) GVG-mix fish food.There was a relatively high loss(i.e.,found dead,euthanized due to scoliosis,or not found) of tadpoles fed with the lettuce/leaf litter alone,but this was increased significantly when supplemented with Wardley Premium Spirulina discs,either alone or with Sera~(TM) GVG-mix fish food,and Sera~(TM) GVG fish food alone.However,the survived tadpoles fed on the three supplements were all heavier after three weeks and at metamorphosis than those fed with lettuce/leaf litter alone,and reached metamorphosis quicker.It is concluded that any benefit of the food supplements in terms of increasing the rate of growth and development of the tadpoles is outweighed by greater mortality.There is now a need for the efficient rearing of tadpoles,many from novel species that need complex habitats.Further studies of diet are required due to the current conservation crisis of amphibians.

Little Tadpoles Look for Mummy!

人物:D—Mummy Duck F—Mummy FishFr—Mummy Frog G—Mummy GooseT—Mummy TortoiseTs （T1,T2,T3,T4,T5,T6） —Six little tadpolesScene ⅠT1:Spring is coming.The water turns warm.The grass and leaves turn green.Howbeautiful!How sweet!Ts:（sing）One,two,three,four,five,

999 TADPOLES

What’s new?英语绘本屋里装着很多新鲜事儿。大家听说过天上掉树叶、雨点儿、雪花、冰雹,听说过天上掉青蛙吗.·很多很多青蛙从天而降,而且是一家人,不不,应该说一家蛙。Mother and Father and 999young frogs fell down from the sky.999只小青蛙和爸爸妈妈从天而降。新单词:fall:v.掉下fall down from…:从…掉下来·青蛙怎么会飞上天?

A neglected risk for sparganosis:eating live tadpoles in central China

A 29-year-old farmer from central China was sent into the Emergency Department of the Affiliated Hospital of Zhengzhou University.He had a 15-day history of persistent high fever,abdominal distention and pain.The patient was clinically diagnosed as appendicitis and peritonitis,and treated with antibiotics in a local hospital,did not improve.On exploratory laparotomy,the appendicular perforation and peritonitis were seen;appendicectomy were performed,and antibiotics were given.However,high fever and abdominal pain still persisted;intestinal adhesion and obstruction,ascites appeared.He was given the“critically ill notice”.He had eosinophilia(12.95%)and the history of eating live frog tadpoles for treating his cutaneous pruritus 3 days before onset of the disease.Serum anti-sparganum antibodies assayed by ELISA were positive.This patient has hospitalized for one and half months and spend more than US$12000.This patient was primarily diagnosed as visceral sparganosis,and cured with praziquantel.Sparganosis is one neglected but important parasitic zoonosis of poverty.Human infections were mainly acquired by eating raw or uncooked meat of frogs and snakes infected with plerocercoids,using frog or snake flesh as poultices,or drinking raw water contaminated with infected copepods.However,sparganosis caused by ingestion of live tadpoles are emerging in central China.Our surveys showed that 11.93%of tadpoles in Henan province are infected with plerocercoids.Eating live tadpoles is a high risk for sparganum infection.The comprehensive public health education should be carried out for people in endemic areas and the bad habit of eating live tadpoles must be discouraged.

Time to feed： How diet, competition, and experience may influence feeding behaviour and cannibalism in wood frog tadpoles Lithobates sylvaticus

Wood frog Lithobates sylvaticus tadpoles develop in temporary wetlands where high population densities can force tadpoles into aggregations that intensify competition and can lead to cannibalism. However, chemical alarm cues released from injured conspecifics could also dissuade cannibalism. The purpose of this study was to test mechanisms that may influence can- nibalistic behaviour. We tested whether the tendency of tadpoles to consume conspecifics would increase with the presence of competition and/or cues of profitable diets. Tadpoles placed in 1L experimental containers were tested for feeding initiation times of multiple diets, including conspecific tissues and conspecific tissues combined with chemical cues from the alternative diets （brine shrimp and comrneal）. Tadpoles were tested in the presence and absence of a competitor, and at multiple times over the course of the study. Tadpoles exhibited an altered response to diets over time; however the presence of a competitor reduced re- sponse times to all diets including conspecific tissues. Similarly, the presence of specific diets also reduced the response time of tadpoles to conspecific tissues. These results suggest competition among feeding tadpoles could result in aggressive behaviour leading to indiscriminate predation and cannibalism [Current Zoology 60 （5）： 571-580, 2014 ].

THE STUDY OF EARLY DEVELOPMENT AND EVOLUTION OF Torrentophryne aspinia

Torrentophryne aspinia is a new kind of toads discovered in China recently, it lives in the forest floor in West Yunnan, the most important things for this kind of species is that they have a kind of torrent-adapted tadpoles which have abdominal suckers and can adhere to the surfaces of rocks in moving waters. In this article, we described the forming procedures of abdominal sucker and some breeding behaviors, habitats and habits. After comparing with those of other toads, it is confirmed that Torrentophryne should be a new valid genus, it is derived from ancestor toads because of adaptation to the torrent habitats, by the forming of torrent -adapted organ-abdominal sucker in the early development.

Evaluation of the Genotoxicity of Chlorpyrifos in Common Indus Valley Toad, <i>Bufo stomaticus</i>Using Alkaline Single-Cell Gel Electrophoresis (Comet) Assay

Chlorpyrifos is a commonly used pesticide of organophosphate group, which causes toxicological effects in non-target organisms especially fish and frogs. In the present study, the genotoxicity of sublethal concentrations of chlorpyrifos was observed in the erythrocytes of common Indus valley toad, Bufo stomaticus, using the Alkaline Single-Cell Gel Electrophoresis (Comet) assay. In the first step, acute toxicity of chlorpyrifos was evaluated by exposing the tadpoles to high concentrations of the pesticide. The acute LC50 value of chlorpyrifos, calculated by Trimmed Spearman-Karber (TSK) in static bioassay, was found to be 930.0 μg/L. On the basis of acute LC50 value, the tadpoles were exposed to three sublethal concentrations (155, 233 and 465 μg/L) of chlorpyrifos for 96 h. Blood cells were collected at every 24 h interval and were subjected to the Alkaline Single-Cell Gel Electrophoresis assay. The observed DNA damage was concentration and time-dependent, and those levels of DNA damage in between the tested concentrations and times were significantly different (p < 0.05). The tadpoles exposed to different concentrations of chlorpyrifos also showed different morphological abnormalities. It was concluded that chlorpyrifos is a genotoxic pesticide causing DNA damage in Bufo stomaticus.

Changes on Anuran Tadpole Functional Diversity along an Environmental Gradient at the Southernmost Atlantic Rainforest Remnant

For decades the ecologists are using the same methods in order to determine the environmental health of a community,however,the crescent need on defining how these processes act,triggered the development of new methods that could classify the organisms and their function at the habitats.Here we used the anuran larvae to understand the effects of an environmental gradient on the structure and organization of the anuran assemblages along it,and to access in a realistic form,the actual state of preservation of the la rgest remnant of Atlantic Rainforest on the Southernmost portion of Brazil.We found that despite the higher diversity of species and the conservation unit status of the place,the ecosystem itself is still in danger,given the low number of functional groups and thus a higher number of ecosystem services that can be lost.

Pesticide-Induced Alterations of Esterase and Antioxidant Enzymes of Aquatic Organisms Oreochromis mossambicus and Xenopus laevis

Pesticides are extensively utilized in modern farming to control pests and weeds, thereby ensuring high quality and quantity of crops. Aerial drifts and runoffs after rain transport these agrochemicals to aquatic bodies, where they adversely affect aquatic organisms. We carried out a study to assess the effects of carbaryl and dimethoate on esterase and antioxidant enzyme activities of tadpoles, adult frogs and juvenile fish. These organisms were exposed to sublethal contraptions of 2.9 ppm carbaryl and 4.8 ppm dimethoate for 96 hours. After the exposure period, the fish and frogs were sacrificed and post-mitochondrial fractions were prepared for enzymatic analysis. Acetylcholinesterase (AChE), carboxylesterase (CbE), superoxide dismutase, glutathione peroxidase and catalase were measured. Carbaryl and dimethoate inhibited the activities of acetylcholinesterase, carboxylesterase, superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx) in juvenile fish, tadpoles and adult frogs. Inhibition of SOD, CAT and GPx suggests that the two pesticides caused oxidative stress in the aquatic organisms, while inhibition of AChE and CbE affected the normal transmission of nerve impulses. The results indicate that the two pesticides affect the well-being of the studied aquatic organisms.

高抗氧化活性lager型啤酒酵母选育

采用过氧化氢刺激lager型啤酒酵母,Tadpoling法筛选细胞活力恢复较快突变菌,根据各菌株线粒体膜电位、胞内氧自由基(ROS)水平筛选获得4株活性较高菌株。比较突变菌与原始菌传代发酵性能、胞内ROS、活力指标及每一代细胞死亡率水平,最终获得一株抗氧化能力提高且活力稳定性较高啤酒酵母菌株。分析验证突变菌线粒体DNA修复相关基因MHR1发现,该基因发生部分碱基突变。

Observations on the morphology of embryonic and larval development in Styela canopus Savigny

The morphological characters on different developmental phases of embryo and larva and the schedule of the whole early developmental process in Styela canopus were observed and described. The types of reproduction and early development as well as the morphology, of egg and larva in different ascidian species were compared. Styela canopus is oviparous. Its egg, 230.4 similar to 336.0 mum in diameter, is equipped with extraembryonic cell layers measured 43.2 similar to 63.0 mum thick. The early development of Styela canopus is typical urodele development, including fertilization, cleavage, gastrulation, tadpole in membrane, tadpole, initiating metamorphosis and juvenile. The tadpole of Styela canopus, with a length of 0.6 similar to 0. 9 mm, consists of trunk and tail. There are obvious notochord, ocellus and adhesive papillae in the tadpole. Under the water temperature of (25 +/- 0-5) degreesC and the salinity of 27.0, the larva was hatched after 9.5 similar to 11.0 h since the fertilization.