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Oh, Hye-Ji, Kwang-Hyeon Chang, Mei-Yan Jin, Jong-Mo Suh, Ju-Duk Yoon, Kyung-Hoon Shin, Su-Gon Park e Min-Ho Chang. "Trophic Ecology of Endangered Gold-Spotted Pond Frog in Ecological Wetland Park and Rice Paddy Habitats". Animals 11, n. 4 (31 marzo 2021): 967. http://dx.doi.org/10.3390/ani11040967.
Testo completoAbstract (sommario):
The gold-spotted pond frog (Pelophylax chosenicus) is an endangered amphibian species in South Korea. In order to obtain ecological information regarding the gold-spotted pond frog’s habitat environment and biological interactions, we applied stable isotope analysis to quantify the ecological niche space (ENS) of frogs including black-spotted pond frogs (P. nigromaculatus) and bullfrogs (Lithobates catesbeianus) within the food web of two different habitats—an ecological wetland park and a rice paddy. The gold-spotted pond frog population exhibited a broader ENS in the ecological wetland park than in the rice paddy. According to the carbon stable isotope ratios, gold-spotted pond frogs mainly fed on insects, regardless of habitat type. However, the results comparing the range of both carbon and nitrogen stable isotopes showed that gold-spotted pond frogs living in the rice paddy showed limited feeding behavior, while those living in the ecological wetland park fed on various food sources located in more varied trophic positions. Although the ENS of the gold-spotted pond frog was generally less likely to be overlapped by that of other frog species, it was predicted to overlap with a high probability of 87.3% in the ecological wetland park. Nevertheless, gold-spotted pond frogs in the ecological wetland park were not significantly affected by the prey competition with competitive species by feeding on other prey for which other species’ preference was low. Since these results show that a habitats’ food diversity has an effect on securing the ENS of gold-spotted pond frogs and prey competition, we recommend that the establishment of a food environment that considers the feeding behavior of gold-spotted pond frogs is important for the sustainable preservation of gold-spotted pond frogs and their settlement in alternative habitats.
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KORNILOVA, N. V., V. G. ABUSHKEVICH, A. N. ARDELYAN, Yu Yu PEROVA e A. G. POKHOT'KO. "VISUALIZATION OF THE EXCITATION PROCESS IN THE FROG'S NERVES". Kuban Scientific Medical Bulletin 25, n. 4 (3 ottobre 2018): 51–54. http://dx.doi.org/10.25207/1608-6228-2018-25-4-51-54.
Testo completoAbstract (sommario):
Aim.Visualization of the excitation process in the frog's nerves.Materials and methods. Observations were carried out on 30 immobilized frogs. Vagosympathetic trunks and sciatic nerve were allocated from the frogs. Ligatures were placed on the right vagosympathetic trunk crossing it. A scanner of the gas discharge visualization camera of the CELSY device, which created a high- frequency electromagnetic field (1024 Hz), was installed above the nerves. The scanner with a highly sensitive camera shot a 60-second video (the frequency of frame-by-frame shooting to 1000 frames per second), during which the edge luminescence (Kirlian effect) and the glow spots were recorded inside the nerve. The electrocardiogram (ECG) was synchronously recorded in the I standard lead. The processing of the obtained results was carried out according to the area of the glow spot, the area of the highest luminescence brightness, the direction of the movement of the foci of the luminescence, and the linear velocity of the movement of the glow foci.Results.Foci of the internal luminescence appeared only in the high-frequency electromagnetic field in the sciatic nerve of the frog when the nerve was stimulated by electrical impulses, which resulted in the contraction of the frog's foot. Glow foci of the brain synchronous to the heart rhythm and preceding the tooth of the V- wave on the frog’s ECG were observed at the central end of the cut of the frog’s vagosympathetic trunk. Conclusion.Visualized foci of luminescence in the nerve reflect the neural activity.
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Lenin, Kanagasabai. "Factual Power Loss Diminution by Enhanced Frog Leaping Algorithm". Journal of Applied Science, Engineering, Technology, and Education 3, n. 2 (2 luglio 2020): 114–18. http://dx.doi.org/10.35877/454ri.asci112.
Testo completoAbstract (sommario):
This paper proposes Enhanced Frog Leaping Algorithm (EFLA) to solve the optimal reactive power problem. Frog leaping algorithm (FLA) replicates the procedure of frogs passing though the wetland and foraging deeds. Set of virtual frogs alienated into numerous groups known as “memeplexes”. Frog’s position’s turn out to be closer in every memeplex after few optimization runs and certainly, this crisis direct to premature convergence. In the proposed Enhanced Frog Leaping Algorithm (EFLA) the most excellent frog information is used to augment the local search in each memeplex and initiate to the exploration bound acceleration. To advance the speed of convergence two acceleration factors are introduced in the exploration plan formulation. Proposed Enhanced Frog Leaping Algorithm (EFLA) has been tested in standard IEEE 14,300 bus test system and simulation results show the projected algorithm reduced the real power loss considerably.
4
Sugiura, Shinji. "Anti-predator defences of a bombardier beetle: is bombing essential for successful escape from frogs?" PeerJ 6 (30 novembre 2018): e5942. http://dx.doi.org/10.7717/peerj.5942.
Testo completoAbstract (sommario):
Some animals, such as the bombardier beetles (Coleoptera: Carabidae: Brachinini), have evolved chemical defences against predators. When attacked, bombardier beetles can discharge noxious chemicals at temperatures of approximately 100 °C from the tip of their abdomens, “bombing” their attackers. Although many studies to date have investigated how bombardier beetles discharge defensive chemicals against predators, relatively little research has examined how predators modify their attacks on bombardier beetles to avoid being bombed. In this study, I observed the black-spotted pond frog Pelophylax nigromaculatus (Anura: Ranidae) attacking the bombardier beetle Pheropsophus jessoensis under laboratory conditions. In Japan, Pe. nigromaculatus is a generalist predator in grasslands where the bombardier beetle frequently occurs. Almost all the frogs (92.9%) observed rejected live bombardier beetles; 67.9% stopped their attacks once their tongues touched the beetles, and 25.0% spat out the beetles immediately after taking the beetles into their mouths. No beetle bombed a frog before being taken into a frog’s mouth. All beetles taken into mouths bombed the frogs. Only 7.1% of the frogs swallowed live bombardier beetles after being bombed in the mouth. When dead beetles were provided instead, 85.7% of the frogs rejected the dead beetles, 71.4% stopped their attacks after their tongues touched the beetles, and 14.3% spat out the beetles. Only 14.3% of the frogs swallowed the dead beetles. The results suggest that the frogs tended to stop their predatory attack before receiving a bombing response from the beetles. Therefore, bombing was not essential for the beetles to successfully defend against the frogs. Using its tongue, Pe. nigromaculatus may be able to rapidly detect a deterrent chemical or physical characteristics of its potential prey Ph. jessoensis and thus avoid injury by stopping its predatory attack before the beetle bombs it.
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Chuang, Tsai-Fu, e Yuan-Hsiou Chang. "A New Design Concept of an Ecological Corridor for Frogs to Improve Ecological Conservation". Sustainability 13, n. 20 (10 ottobre 2021): 11175. http://dx.doi.org/10.3390/su132011175.
Testo completoAbstract (sommario):
Ecological corridors are an essential element in conserving the biodiversity and proper functioning of ecosystems. Without their connectivity, a very large number of species would not have access to all of the habitats needed for their life cycles. Although the concept of an ecological corridor has been discussed for many years, few studies on ecological corridors for frogs have been conducted. Frogs are often considered to be a keystone species. They are a good indicator of habitat health, and they are often the first to be harmed by pollution or ecosystem deterioration. However, there have been reports of frogs crossing ecological corridors and being attacked or consumed by natural enemies. It is vital to create ecological corridors for frogs that allow them to migrate quickly and safely. The purpose of this study was to propose a new ecological corridor design concept for frogs to address the limitations mentioned above. In this paper, grey system theory was employed to offer the necessary information for the frog ladder’s design. In addition, the frog’s high jump capacity and its defense mechanisms against natural enemies were used to determine the rest space and shelter.
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McCAY, MICHAEL G. "AERODYNAMIC STABILITY AND MANEUVERABILITY OF THE GLIDING FROG POLYPEDATES DENNYSI". Journal of Experimental Biology 204, n. 16 (15 agosto 2001): 2817–26. http://dx.doi.org/10.1242/jeb.204.16.2817.
Testo completoAbstract (sommario):
SUMMARY Gliding has evolved independently in two families of tree frog. Tree frogs glide to descend rapidly to mating sites over temporary pools on the forest floor or to escape predators. The physical mechanisms used by frogs to glide and maneuver were investigated using a combination of observations of live frogs (Polypedates dennysi) gliding in a tilted wind-tunnel and aerodynamic forces and torques measured from physical models of tree frogs in a wind-tunnel. Tree frogs maneuvered in the tilted wind-tunnel using two different turning mechanisms: a banked turn (the frog rolls into the turn) and a crabbed turn (the frog yaws into the turn). Polypedates dennysipossessed overall weak aerodynamic stability: slightly stable about the pitch and roll axis, slightly unstable about the yaw axis. The maneuverability of gliding tree frogs was quantified using a maneuverability index. The maneuverability of tree frogs was roughly equivalent for tree frogs performing a banked turn and performing a crabbed turn. The maneuverability of tree frogs was approximately one-third of the maneuverability of a falcon (Falcon jugger).
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Wang, Shuqi, Jizhuang Fan e Yubin Liu. "Simulation Analysis of Frog-Inspired Take-Off Performance Based on Different Structural Models". Biomimetics 9, n. 3 (11 marzo 2024): 168. http://dx.doi.org/10.3390/biomimetics9030168.
Testo completoAbstract (sommario):
The frog-inspired jumping robot is an interesting topic in the field of biomechanics and bionics. However, due to the frog’s explosive movement and large range of joint motion, it is very difficult to make their structure completely bionic. To obtain the optimal jumping motion model, the musculoskeletal structure, jumping movement mechanism, and characteristics of frogs are first systematically analyzed, and the corresponding structural and kinematic parameters are obtained. Based on biological characteristics, a model of the articular bone structure is created, which can fully describe the features of frog movement. According to the various factors affecting the frog’s jumping movement, mass and constraints are added, and the complex biological joint structure is simplified into four different jumping structure models. The jumping ground reaction force, velocity, and displacement of the center of mass, joint torque, and other motion information of these four models are obtained through ADAMS simulation to reveal the jumping movement mechanism and the influencing factors of frogs. Finally, various motion features are analyzed and compared to determine the optimal structural model of the comprehensive index, which provides a theoretical basis for the design of the frog-inspired jumping robot.
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Smith, Lora L., Jennifer M. Howze, Jennifer S. Staiger, Eric R. Sievers, Deborah Burr e Kevin M. Enge. "Added Value: Gopher Tortoise Surveys Provide Estimates of Gopher Frog Abundance in Tortoise Burrows". Journal of Fish and Wildlife Management 12, n. 1 (27 ottobre 2020): 3–11. http://dx.doi.org/10.3996/jfwm-20-030.
Testo completoAbstract (sommario):
Abstract The gopher frog Lithobates capito is one of the most terrestrial frogs in the southeastern United States and often inhabits gopher tortoise burrows Gopherus polyphemus outside of the breeding season. Gopher frog populations have declined, and the species is under review for listing as threatened or endangered under the U.S. Endangered Species Act. Much of our knowledge on the status of gopher frogs is based on detections of larvae at breeding wetlands, which can be challenging because of environmental variability and provides no information on the terrestrial life stages of the species. Therefore, an alternative method is called for. We recorded observations of gopher frogs during gopher tortoise surveys at four conservation lands in Florida and used line-transect distance sampling to estimate frog abundance. We also recorded burrow size, incidence of frog co-occupancy with tortoises, and distance from frog-occupied burrows to breeding wetlands. We observed 274 gopher frogs in 1,097 tortoise burrows at the four sites. The proportion of burrows occupied by gopher frogs among sites ranged from 0.17 to 0.25. Gopher frog abundance in tortoise burrows was 742 (512–1,076 95% CL) at Etoniah Creek State Forest, 465 (352–615) at Ft. White Wildlife Environmental Area, 411 (283–595) at Mike Roess Gold Head Branch State Park, and 134 (97–186) at Watermelon Pond Wildlife Environmental Area. We observed up to four frogs in a single burrow. The proportion of frogs detected in burrows occupied by a gopher tortoise ranged from 0.46 to 0.79 among sites, and overall, gopher frogs preferred burrows occupied by tortoises over unoccupied burrows (χ2 = 15.875; df = 3; P = 0.001). Gopher frogs used burrows from 7 to 43 cm in width; mean width of frog-occupied burrows did not differ from that of unoccupied burrows (F1,3 = 0.049, P = 0.825). Distance from frog-occupied tortoise burrows to the nearest breeding wetland ranged from 141 to 3,402 m. Our data on gopher frogs collected in conjunction with gopher tortoise monitoring efforts using line-transect distance sampling and burrow cameras provided novel information on frog abundance in their terrestrial habitat and required no additional effort. However, the extent to which frogs use tortoise burrows relative to other available refuges (small mammal burrows, stumps, or other structures) is unknown; thus, our estimates should be considered conservative. We suggest that terrestrial abundance estimates for gopher frogs can complement efforts to monitor breeding activity to provide a more comprehensive means of monitoring population trends in this cryptic species.
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Woinarski, J. C. Z., S. M. Legge, L. A. Woolley, R. Palmer, C. R. Dickman, J. Augusteyn, T. S. Doherty et al. "Predation by introduced cats Felis catus on Australian frogs: compilation of species records and estimation of numbers killed". Wildlife Research 47, n. 8 (2020): 580. http://dx.doi.org/10.1071/wr19182.
Testo completoAbstract (sommario):
Abstract ContextWe recently estimated the numbers of reptiles, birds and mammals killed by cats (Felis catus) in Australia, with these assessments providing further evidence that cats have significant impacts on Australian wildlife. No previous studies have estimated the numbers of frogs killed by cats in Australia and there is limited comparable information from elsewhere in the world. AimsWe sought to (1) estimate the numbers of frogs killed by cats in Australia and (2) compile a list of Australian frog species known to be killed by cats. MethodsFor feral cats, we estimated the number of frogs killed from information on their frequency of occurrence in 53 cat dietary studies (that examined stomach contents), the mean number of frogs in dietary samples that contained frogs, and the numbers of cats in Australia. We collated comparable information for take of frogs by pet cats, but the information base was far sparser. Key resultsFrogs were far more likely to be reported in studies that sampled cat stomachs than cat scats. The mean frequency of occurrence of frogs in cat stomachs was 1.5%. The estimated annual per capita consumption by feral cats in Australia’s natural environments is 44 frogs, and, hence, the annual total take is estimated at 92 million frogs. The estimated annual per capita consumption by pet cats is 0.26 frogs, for a total annual kill of one million frogs by pet cats. Thirty native frog species (13% of the Australian frog fauna) are known to be killed by cats: this tally does not include any of the 51 threatened frog species, but this may simply be because no cat dietary studies have occurred within the small ranges typical of threatened frog species. ConclusionsThe present study indicated that cats in Australia kill nearly 100 million frogs annually, but further research is required to understand the conservation significance of such predation rates. ImplicationsThe present study completed a set of reviews of the impacts of cats on Australian terrestrial vertebrates. Cat predation on Australian frogs is substantial, but is likely to be markedly less than that on Australian reptiles, birds and mammals.
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Şereflişan, Hülya, e Ahmet Alkaya. "Türkiye’de Eti Yenilebilen Kurbağaların (Ranidae) Biyolojisi, Ekonomisi, Avcılığı ve İhracatına Yönelik Yasal Mevzuatı". Turkish Journal of Agriculture - Food Science and Technology 4, n. 7 (15 luglio 2016): 600. http://dx.doi.org/10.24925/turjaf.v4i7.600-604.654.
Testo completoAbstract (sommario):
The frogs production is done on the basis of fully hunting, an important export product in Turkey. The frogs are almost no domestic consumption. The frogs are exported to France, Italy, Switzerland, Lebanon, Greece and Spain by five companies a processed form as live frog, frozen frog legs and chilled frog legs. In Turkey, some regulations related to hunting frogs and exports are prepared by under the Ministry of Agriculture and Rural Affairs General Directorate of Protection and Control. The hunting frogs is banned by 3/1 the Commercial Fisheries regulating the hunting notification. These prohibitions are designed to be different for each province. The provinces are permitted for frogs hunting by the legislation in Adana, Afyonkarahisar, Balıkesir, Bingöl, Bursa, Edirne, Bursa, Istanbul and Yalova. Frogs were exported in different amounts (kg) with different price in every year during the last ten years. The highest amounts of the frogs with the lowest of price were exported in 2013. Prey weight is shrinking due to overfishing. In this case, the price of export materials has got significantly negative effects. As a result, the ban on hunting and restrictive measures for protection should be taken seriously in some of the provinces. Hunting ban is absolutely necessary in Turkey. In many countries including Turkey, in order to ensure sustainability, it is important to do the frog breeding.
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McAlpine, Donald F. "Helminth communities in bullfrogs (Rana catesbeiana), green frogs (Rana clamitans), and leopard frogs (Rana pipiens) from New Brunswick, Canada". Canadian Journal of Zoology 75, n. 11 (1 novembre 1997): 1883–90. http://dx.doi.org/10.1139/z97-818.
Testo completoAbstract (sommario):
Twenty-three helminth species were identified from bullfrogs, Rana catesbeiana, green frogs, R. clamitans, and leopard frogs, R. pipiens, in New Brunswick. Digeneans dominated adult helminth communities in the aquatic bullfrog and semi-aquatic green frog; nematodes were dominant in the more terrestrial leopard frog. In green frogs and leopard frogs, richness and abundance were greatest in adults; in bullfrogs, juveniles showed the greatest richness and abundance. An increase in vertebrates in the diet of adult bullfrogs influences helminth communities in bullfrogs. Where Glypthelmins quieta and nematodes, which infect the host by skin penetration, predominate in green frogs and leopard frogs, respectively, the increase in epidermal area with age probably influences helminth abundance. Adult female leopard frogs are larger than males and harbour greater numbers of helminths. Within the most heavily sampled component communities only larval digeneans, and less frequently nematodes with direct life cycles, were common (i.e., in > 50% of hosts); other taxa were generally present at prevalences of < 20% and intensities of < 10 helminths per frog. Although wetland characteristics and helminth transmission dynamics play a role in producing variation in helminth communities among sites, ontogenetic shifts in diet and sexual size dimorphism within these anuran species are important in shaping helminth communities in individual frog hosts.
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Cao, Tu Cam, Huong Kim Huynh e Kiem Van Nguyen. "TECHNICAL AND FINANCIAL ANALYSIS OF FROG CULTURE (Rana tigerina) AT TRA VINH PROVINCE". Scientific Journal of Tra Vinh University 1, n. 41 (29 dicembre 2020): 97–103. http://dx.doi.org/10.35382/18594816.1.41.2020.648.
Testo completoAbstract (sommario):
This study was conducted through the direct interview of 90 households applying the alternative system of culturing frogs in Tra Vinh Province from 9/2020 to 3/2020. The study aimed to determine current status of frog farming. The collected data includes the technical and financial aspect of culturing frogs. The results showedthat there are two models of frog farming: culturing frogs in canvas (65.56% of households), and culturing frogs in cages (34.44% of households); Both models applied the same average farming area of 36.27 m2 with stocking density of 115 inds/m2. After 2.6 months of culturing, the average frog size was 257 g. The average frogyield produced 21,024 kg/1,000 m2/crop and the net income of 100 million VND/1,000 m2/crop was achieved. The result indicated that it is easy to raise frogs because the households can take advantage of the surrounding area of their houses for raising frogs and therefore the farmers’ could improve by this method.
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Proença, Diogo Neves, Emanuele Fasola, Isabel Lopes e Paula V. Morais. "Characterization of the Skin Cultivable Microbiota Composition of the Frog Pelophylax perezi Inhabiting Different Environments". International Journal of Environmental Research and Public Health 18, n. 5 (5 marzo 2021): 2585. http://dx.doi.org/10.3390/ijerph18052585.
Testo completoAbstract (sommario):
Microorganisms that live in association with amphibian skin can play important roles in protecting their host. Within the scenarios of global change, it is important to understand how environmental disturbances, namely, metal pollution, can affect this microbiota. The aim of this study is to recognize core bacteria in the skin cultivable microbiota of the Perez frog (Pelophylax perezi) that are preserved regardless of the environmental conditions in which the frogs live. The characterization of these isolates revealed characteristics that can support their contributions to the ability of frogs to use metal impacted environments. Frog’s skin swabs were collected from P. perezi populations that inhabit a metal-polluted site and three reference (non-metal polluted) sites. Bacterial strains were isolated, identified, and subjected to an acid mine drainage tolerance (AMD) test, collected upstream from a site heavily contaminated with metals, and tested to produce extracellular polymeric substances (exopolysaccharide, EPS). All frog populations had Acinetobacter in their cutaneous cultivable microbiota. Significant growth inhibition was observed in all bacterial isolates exposed to 75% of AMD. EPS production was considered a characteristic of several isolates. The data obtained is a preliminary step but crucial to sustain that the cultivable microbiota is a mechanism for protecting frogs against environmental contamination.
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Rhebergen, F., R. C. Taylor, M. J. Ryan, R. A. Page e W. Halfwerk. "Multimodal cues improve prey localization under complex environmental conditions". Proceedings of the Royal Society B: Biological Sciences 282, n. 1814 (7 settembre 2015): 20151403. http://dx.doi.org/10.1098/rspb.2015.1403.
Testo completoAbstract (sommario):
Predators often eavesdrop on sexual displays of their prey. These displays can provide multimodal cues that aid predators, but the benefits in attending to them should depend on the environmental sensory conditions under which they forage. We assessed whether bats hunting for frogs use multimodal cues to locate their prey and whether their use varies with ambient conditions. We used a robotic set-up mimicking the sexual display of a male túngara frog ( Physalaemus pustulosus ) to test prey assessment by fringe-lipped bats ( Trachops cirrhosus ). These predatory bats primarily use sound of the frog's call to find their prey, but the bats also use echolocation cues returning from the frog's dynamically moving vocal sac. In the first experiment, we show that multimodal cues affect attack behaviour: bats made narrower flank attack angles on multimodal trials compared with unimodal trials during which they could only rely on the sound of the frog. In the second experiment, we explored the bat's use of prey cues in an acoustically more complex environment. Túngara frogs often form mixed-species choruses with other frogs, including the hourglass frog ( Dendropsophus ebraccatus ). Using a multi-speaker set-up, we tested bat approaches and attacks on the robofrog under three different levels of acoustic complexity: no calling D. ebraccatus males, two calling D. ebraccatus males and five D. ebraccatus males. We found that bats are more directional in their approach to the robofrog when more D. ebraccatus males were calling. Thus, bats seemed to benefit more from multimodal cues when confronted with increased levels of acoustic complexity in their foraging environments. Our data have important consequences for our understanding of the evolution of multimodal sexual displays as they reveal how environmental conditions can alter the natural selection pressures acting on them.
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Džekčioriūtė, Vita. "Certain Aspects of Mythical Meaning of Frog in the Traditional Lithuanian Worldview". Tautosakos darbai 48 (10 dicembre 2014): 71–88. http://dx.doi.org/10.51554/td.2014.29097.
Testo completoAbstract (sommario):
The article is based on the traditional Lithuanian beliefs and customs recorded in the end of the 19th – first half of the 20th century. It aims at proving that frog in Lithuanian culture has its own unique realm of mythical meanings, which only partly correspond to those of the toad’s. In this realm, several groups of meanings associated with frog can be discerned. Firstly, frog is considered to be an accumulator of water in the popular meteorology. Its enhanced activity, its enlarged body or darkened color may indicate the approach of the rain. People used to believe that killing of a frog resulted in downpour, since such an act symbolically released the atmospheric water that had been accumulated in its body. A second group of mythical meanings associated with frog present it as a creature endowed with healing powers. Here, its cold-bloodedness is most important. Illness or physical malfunction represent the hot pole of the opposition hot vs. cold, while frog represents the cold one, thus being able to neutralize the heat resulting from illness. In the third group, frog is regarded as a zoomorphic part of the human body or as a foreign body embedded in it. A creature in frog’s shape is believed to live in the human belly. As result of physical malfunction, it may move and leave its place, finding itself close to the heart or in the throat. Having lost this part of the body, the person dies. So whenever this frog-like creature, commonly also called macica (womb) or gumbas (lump) moves, it is attempted to restore it back to its former place. Frog, regarded as a foreign body, is believed also to sit on the human brain, thus causing psychic diseases. In such case, the person is treated by attempting to lure the frog out of the body. In the fourth group of mythical meanings, tight connections between frogs and children are displayed. Both frogs and children are related to water and humidity. This idea is reflected in the notion of people being born from a water body. Little children, just like frogs, are characterized by poorly coordinated movements and inarticulate sounds. The smaller the child, the closer it seems to the frog. This association is best reflected by calling little kids frogs in Lithuanian. From such folk identification of children and frogs there also stems the traditional explanation typically given to children by grown-ups, of the children being brought by the stork. In the fifth group of mythical meanings, frog is presented as a threatening aquatic creature, which is used to scare the kids away from water. Frog is therefore considered as possible prototype of all the other scary beings residing in water.
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Allen, Colin. "A Tale of Two Froggies". Canadian Journal of Philosophy Supplementary Volume 27 (2001): 104–15. http://dx.doi.org/10.1080/00455091.2001.10715998.
Testo completoAbstract (sommario):
There once was an ugly duckling. Except he wasn't a duckling at all, and once he realized his error he lived happily ever after. And there you have an early primer from the animal literature on the issue of misrepresentation – perhaps one of the few on this topic to have a happy ending.Philosophers interested in misrepresentation have turned their attention to a different fairy tale animal: the frog. No one gets kissed in this story and the controversial issue of self-recognition is avoided. There are simply some scientifically established facts about ways to get a frog to stick out its tongue. (Who would want to kiss a frog under those conditions, anyway?) Some frogs, it seems, are fairly indiscriminate about sticking out their tongues. Not just flies, but a whole slew of other things will go down the hatch if propelled at just the right velocity and range through a frog's visual field, provoking a tongue-flicking response. Fortunately for us all, frogs seem to be a bit more discriminating about whom they will kiss.
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Böswald, Linda F., Dana Matzek, Helen Mohr, Ellen Kienzle e Bastian Popper. "Morphometrics of Xenopus laevis Kept as Laboratory Animals". Animals 12, n. 21 (30 ottobre 2022): 2986. http://dx.doi.org/10.3390/ani12212986.
Testo completoAbstract (sommario):
Morphometric data that provide information on body conditions can be used to monitor the health and well-being of animals. In laboratory animals, they can help to evaluate the stress due to experiments or treatments, following the 3R principles. The aim of the present study was to obtain morphometric data of male and female African clawed frogs, Xenopus laevis, as the bases for body condition evaluations. Adult frogs (n = 198) were weighed and standardized photographs were taken. The photographs were used to determine several measurements (length, cranial width, caudal width, thigh width). In addition, a triangle was drawn to outline each frog’s simplified body form, and the triangle surface was calculated. In conclusion, the triangle surface drawn on the dorsal plane of each frog correlated with the body weight of the females. There were significant differences between the body weights and sizes of male and female frogs, with males being smaller (p < 0.001). Based on the morphometric data, females could be assigned to five groups in which an assessment of the animal’s well-being is feasible.
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Seburn, David C., e Kari Gunson. "Has the Western Chorus Frog (Pseudacris triseriata) Declined in Western Ottawa, Ontario?" Canadian Field-Naturalist 125, n. 3 (1 luglio 2011): 220. http://dx.doi.org/10.22621/cfn.v125i3.1224.
Testo completoAbstract (sommario):
To determine whether the Western Chorus Frog has declined in western Ottawa, we conducted auditory surveys at historical locations as well as at various other wetlands. Western Chorus Frogs were detected at 12 of 18 historical locations. Wetland habitat remained at all historical locations where the species was not detected. There was no difference in the year of historical records for sites where Western Chorus Frogs were (median 1987.5) and were not (median 1987.5) detected. In the present study, Western Chorus Frogs were also detected at 30 locations where they had not been previously reported. Historical sites where Western Chorus Frogs were not detected were not significantly farther away from known Western Chorus Frog sites (median distance: 2.2 km) than historical sites where Western Chorus Frogs were detected (median distance: 1.4 km). Land use variables for historical sites where Western Chorus Frogs were and were not detected did not vary significantly at any spatial scale from 0.5 to 2.0 km. Western Chorus Frogs were detected in areas with up to 50% forest cover and up to 86% agricultural cover at the 1.0-km radius. The lack of historical data makes it difficult to assess the current status of the Western Chorus Frog in western Ottawa. The species may have declined, remained approximately the same (by shifting to different breeding sites), or even increased its distribution (by colonizing additional sites).
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Flud, Gabrielle, Julie Angle, Monique N. Simon e Daniel S. Moen. "Functional Frogs". American Biology Teacher 85, n. 8 (1 ottobre 2023): 448–53. http://dx.doi.org/10.1525/abt.2023.85.8.448.
Testo completoAbstract (sommario):
Evolution by natural selection and adaptation are core concepts in biology that students must see and correctly understand their meaning. However, using these concepts in evidence-based learning strategies in the classroom is a difficult task. Here, we present a 5E lesson plan to address the Next Generation Science Standards performance expectation HS-LS4-4, to “construct an explanation based on evidence for how natural selection leads to adaptation of populations.” The Functional Frogs lesson provides multiple hands-on activities to engage students in the development of hypotheses, collection and analysis of empirical data on frog swimming, presentation of results, and construction of explanations supported by evidence for the results. The lesson’s central idea is for students to understand the trait values that provide an advantage in the aquatic environment, increasing a frog’s survival. The link between morphological changes and survival is used to explain how natural selection acts on populations, leading to adaptive evolution.
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Bonde, Joshua W., Peter A. Druschke, Richard P. Hilton, Amy C. Henrici e Stephen M. Rowland. "Preservation of latest Cretaceous (Maastrichtian)—Paleocene frogs (Eorubeta nevadensis) of the Sheep Pass Formation of east-central Nevada and implications for paleogeography of the Nevadaplano". PeerJ 8 (3 luglio 2020): e9455. http://dx.doi.org/10.7717/peerj.9455.
Testo completoAbstract (sommario):
Here we report on exceptional preservation of remains of the frog Eorubeta nevadensis in deposits of the Sheep Pass Formation, ranging from Late Cretaceous to Eocene, in the south Egan Range, Nevada. This formation represents a lacustrine basin within the Sevier retroarc hinterland. The formation is subdivided into six members (A–F); of interest here are members B and C. The base of member B is ?uppermost Cretaceous-Paleocene, while member C is Paleocene. Member B frogs are preserved in three taphonomic modes. Mode 1 frogs are nearly complete and accumulated under attritional processes, with frogs settling on microbial mats, as evidenced by crenulated fabric of entombing limestone. Mode 2 involves accumulation of frogs as a result of attritional processes. These frogs are mostly complete with some showing evidence of invertebrate scavenging. Possible scavengers are gastropods, ostracods, and decapods. Mode 3 is represented by isolated, reworked remains of frogs as a result of storm activity, supported by the association of elements with disarticulated bivalves and mud rip-up clasts. Member C preserves frogs in two taphonomic modes. Mode 4 are nearly complete frogs that accumulated during discrete mass mortality events. Numerous individuals are preserved along bedding planes in identical preservational states. Mode 5 is beds of frog bone hash, which represent increased energy to the depositional system (likely tempestites) and reworking of previously buried frog remains. Taphonomy of the frogs, along with the associated fauna and flora, are consistent with preservation in a cool, temperate lake basin, supporting previous interpretations that the Nevadaplano was an elevated plateau during the late Cretaceous through the Eocene. This is a period of time coincident with a climatic thermal optimum, thus the most parsimonious explanation for a temperate lake at the latitude of east-central Nevada is to invoke high elevation, which is consistent with independent structural and clumped stable isotope studies.
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Tong, Qing, Xiao-peng Du, Zong-fu Hu, Li-yong Cui e Hong-bin Wang. "Modelling the growth of the brown frog (Rana dybowskii)". PeerJ 6 (16 maggio 2018): e4587. http://dx.doi.org/10.7717/peerj.4587.
Testo completoAbstract (sommario):
Well-controlled development leads to uniform body size and a better growth rate; therefore, the ability to determine the growth rate of frogs and their period of sexual maturity is essential for producing healthy, high-quality descendant frogs. To establish a working model that can best predict the growth performance of frogs, the present study examined the growth of one-year-old and two-year-old brown frogs (Rana dybowskii) from metamorphosis to hibernation (18 weeks) and out-hibernation to hibernation (20 weeks) under the same environmental conditions. Brown frog growth was studied and mathematically modelled using various nonlinear, linear, and polynomial functions. The model input values were statistically evaluated using parameters such as the Akaike’s information criterion. The body weight/size ratio (Kwl) and Fulton’s condition factor (K) were used to compare the weight and size of groups of frogs during the growth period. The results showed that the third- and fourth-order polynomial models provided the most consistent predictions of body weight for age 1 and age 2 brown frogs, respectively. Both the Gompertz and third-order polynomial models yielded similarly adequate results for the body size of age 1 brown frogs, while the Janoschek model produced a similarly adequate result for the body size of age 2 brown frogs. The Brody and Janoschek models yielded the highest and lowest estimates of asymptotic weight, respectively, for the body weights of all frogs. TheKwlvalue of all frogs increased from 0.40 to 3.18. TheKvalue of age 1 frogs decreased from 23.81 to 9.45 in the first four weeks. TheKvalue of age 2 frogs remained close to 10. Graphically, a sigmoidal trend was observed for body weight and body size with increasing age. The results of this study will be useful not only for amphibian research but also for frog farming management strategies and decisions.
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Folt, Brian, e Craig Guyer. "Habitat-dependent effects of predatory spiders on prey frogs in a Neotropical wet forest". Journal of Tropical Ecology 37, n. 5 (16 agosto 2021): 214–21. http://dx.doi.org/10.1017/s0266467421000274.
Testo completoAbstract (sommario):
AbstractIn seasonal wet Neotropical forests, many studies have suggested that species-rich terrestrial frog assemblages are regulated bottom-up by the abundance of leaf litter. However, terrestrial frogs are prey to a diverse community of predators, and no studies have tested for top-down effects of predators on this or other anuran assemblages. Here, we used an extensive field dataset to model the relative contribution of food resources, microhabitat resources and predators towards the occupancy and detection of two frog species (Craugastor bransfordii and Oophaga pumilio) at La Selva, Costa Rica. Frog occupancy was most strongly influenced by predatory spiders and secondarily influenced by the abundance of leaf litter. Predators exerted stronger effects on frogs than food resources, and frogs avoided predators more as leaf litter decreased. Detection probability was elevated when predators were present. We found support for bottom-up effects of leaf litter on the terrestrial frog assemblage, but top-down effects by predators exerted stronger effects on frog occupancy and detection. Because predator avoidance varied along a resource gradient, predator and resource effects appear to be dependent, supporting interactions between top-down and bottom-up mechanisms. Climate-driven decreases in leaf litter may drive decreased availability of frog refugia and increased interactions between frogs and predators.
23
Hazell, Donna. "Frog ecology in modified Australian landscapes: a review". Wildlife Research 30, n. 3 (2003): 193. http://dx.doi.org/10.1071/wr02075.
Testo completoAbstract (sommario):
Frog decline in Australia has often occurred where habitat is relatively intact. Habitat alteration and loss do, however, threaten many species. Widespread degradation of aquatic and terrestrial systems has occurred since European settlement, with only 6.4% of Australia's landmass reserved for conservation. But what do we know about how frogs use modified Australian landscapes? Do wildlife managers have the information required to ensure that frog habitat is considered in the management and revegetation of these areas? This review examines published Australian research on frogs to determine knowledge on processes of habitat loss and degradation. Literature that informs landscape restoration and revegetation is also examined to determine whether the habitat needs of frogs are considered. While many threats associated with frog habitat loss and change have been identified there is little quantitative information on frog–habitat relationships in modified landscapes, habitat fragmentation or knowledge of the connectivity required between terrestrial and aquatic frog habitat. Without this information frogs have largely been ignored in efforts to revegetate and manage for the conservation of Australian biota outside reserves. Ecological frog research in modified landscapes is required to avoid land-management decisions and conservation strategies based on inappropriate assumptions of how biota respond to landscape change.
24
Rowley, Jodi J. L., e Corey T. Callaghan. "The FrogID dataset: expert-validated occurrence records of Australia’s frogs collected by citizen scientists". ZooKeys 912 (17 febbraio 2020): 139–51. http://dx.doi.org/10.3897/zookeys.912.38253.
Testo completoAbstract (sommario):
This dataset represents expert-validated occurrence records of calling frogs across Australia collected via the national citizen science project FrogID (http://www.frogid.net.au). FrogID relies on participants recording calling frogs using smartphone technology, after which point the frogs are identified by expert validators, resulting in a database of georeferenced frog species records. This dataset represents one full year of the project (10 November 2017–9 November 2018), including 54,864 records of 172 species, 71% of the known frog species in Australia. This is the first instalment of the dataset, and we anticipate providing updated datasets on an annual basis.
25
Hoshina, Hideto. "Kajika Frogs (Buergeria buergeri) as Premium Pets During the Japanese Modern Monarchical Period". Ethnobiology Letters 11, n. 1 (18 settembre 2020): 96–102. http://dx.doi.org/10.14237/ebl.11.1.2020.1672.
Testo completoAbstract (sommario):
This study reviews articles about the prices of Kajika frogs (Buergeria buergeri) in eight Japanese newspapers published between 1884 and 1938. Frog prices have been converted to present-day United States dollars (US$). The frogs had a wide range of prices. Premium individuals, in particular, were often sold for US$1,000–2,000. In this paper, I discuss the reasons why exceptional individuals were traded at a high price in the market, although Kajika frogs were a common native species. Other topics, such as the presentation of frogs as gifts to royal families, are also discussed.
26
Folt, Brian, e Witold Lapinski. "New observations of frog and lizard predation by wandering and orb-weaver spiders in Costa Rica". Phyllomedusa: Journal of Herpetology 16, n. 2 (21 dicembre 2017): 269. http://dx.doi.org/10.11606/issn.2316-9079.v16i2p269-277.
Testo completoAbstract (sommario):
Studies have suggested that predation by spiders may be an important force regulating life history in neotropical frogs and lizards, but detailed descriptions of predator-prey relationships are few. Here we describe novel observations where spiders contributed to the mortality of frogs and lizards in northeastern Costa Rica, and we corrected or clarified three identification errors of spiders from the literature. The most frequently observed predators were wandering spiders (Ctenidae), which seem to be generalist predators on frogs and lizards. An orb-weaver spider (Araneidae) also contributed to frog mortality, likely after the frog became entangled in the spider’s web. More detailed studies are needed to elucidate the role that spider predation contributes to frog and lizard demography in neotropical forests.
27
CUNNINGHAM, A. A., A. D. HYATT, P. RUSSELL e P. M. BENNETT. "Experimental transmission of a ranavirus disease of common toads (Bufo bufo) to common frogs (Rana temporaria)". Epidemiology and Infection 135, n. 7 (5 febbraio 2007): 1213–16. http://dx.doi.org/10.1017/s0950268807007935.
Testo completoAbstract (sommario):
SUMMARYDuring investigations of epidemic frog mortality in Britain, a novel fatal systemic haemorrhagic disease of common toads was discovered. This disease resembles a systemic haemorrhagic disease of common frogs in Britain, which is one of a range of fatal disease syndromes, characterized by systemic haemorrhages, skin ulceration or a combination of these lesions, caused by ranavirus infection. Ranavirus previously isolated from diseased toads was inoculated into common frogs to evaluate if this virus could infect and cause disease in common frogs. All virus-inoculated frogs died with systemic haemorrhages between 6 and 8 days post-inoculation, giving similar results to those produced by the inoculation of frogs with ranavirus cultured from naturally diseased frogs. These results indicate that the same, or similar, viruses are affecting both frogs and toads in the field and confirm that ranavirus has emerged as an important cause of amphibian mortality in Britain.
28
Vargas-Salinas, Fernando, e Adolfo Amézquita. "Traffic noise correlates with calling time but not spatial distribution in the threatened poison frog Andinobates bombetes". Behaviour 150, n. 6 (2013): 569–84. http://dx.doi.org/10.1163/1568539x-00003068.
Testo completoAbstract (sommario):
Acoustically communicating species have evolved adaptations that allow them to transmit information and overcome signal masking where their habitat is disturbed by anthropogenic noise. To investigate whether calling behaviour or spatial distribution is related to road traffic noise we studied the poison frog Andinobates bombetes in a mid-elevation forest remnant that has been exposed to heavy traffic noise throughout more than four decades. To test whether frogs avoid call during noise episodes generated by passing trucks, we compared background noise levels between calling and non-calling times. To test whether traffic noise is correlated with frogs spatial distribution, we measured frog abundance, ambient noise, and environmental covariates throughout a set of 24 sampling plots between 15 and 300 m from two forest edges, one bordered by the road and another one by an agricultural field. Frogs called more often when traffic noise level was lower. Frogs abundance was only marginally correlated with distance to noisy edges but was predictable from the abundance of bromeliad tanks, an alleged limiting resource for their reproduction. Apparently, to avoid calling during episodes with higher noise level allowed frogs to reduce the detrimental masking effects of anthropogenic noise; if so, it would explain why frog distribution is poorly correlated with distance to the noisy road.
29
LaDouceur, Elise E. B., Amanda M. Hauck, Michael M. Garner, Andrew N. Cartoceti e Brian G. Murphy. "Odontomas in Frogs". Veterinary Pathology 57, n. 1 (24 settembre 2019): 147–50. http://dx.doi.org/10.1177/0300985819877633.
Testo completoAbstract (sommario):
Odontomas are variably differentiated, hamartoma-like proliferations of odontogenic epithelium, pulp ectomesenchyme (odontoblasts), and dental matrix. Frogs are polyphyodont and homodont. Their teeth also differ from mammals in that they are restricted to the upper jaw in adults and lack a periodontal ligament and cementum, attaching directly to the underlying bone. Odontomas were identified in an African clawed frog ( Xenopus laevis), a false tomato frog ( Dyscophus guineti), and a tomato frog of unknown species ( Dyscophus sp.). All of the examined odontomas were composed of numerous tooth-like structures comprising an arc of dentinal matrix lined on the convex surface by ameloblasts and on the concave surface by odontoblasts. Masson’s trichrome and immunohistochemistry with pan-cytokeratin supported these findings. The pathogenesis of these lesions may be displacement of the dental lamina, which has been shown in research studies to lead to de novo proliferation of dental elements in frogs.
30
Aihara, Ikkyu, Ryu Takeda, Takeshi Mizumoto, Takuma Otsuka e Hiroshi G. Okuno. "Size Effect on Call Properties of Japanese Tree Frogs Revealed by Audio-Processing Technique". Journal of Robotics and Mechatronics 29, n. 1 (20 febbraio 2017): 247–54. http://dx.doi.org/10.20965/jrm.2017.p0247.
Testo completoAbstract (sommario):
[abstFig src='/00290001/23.jpg' width='300' text='Calling behavior of a male Japanese Tree Frog' ] Sensing the external environment is a core function of robots and autonomous mechanics. This function is useful for monitoring and analyzing the ecosystem for our deeper understanding of the nature and accomplishing the sustainable ecosystem. Here, we investigate calling behavior of male frogs by applying audio-processing technique on multiple audio data. In general, male frogs call from their breeding site, and a female frog approaches one of the males by hearing their calls. First, we conducted an indoor experiment to record spontaneous calling behavior of three male Japanese tree frogs, and then separated their call signals according to independent component analysis. The analysis of separated signals shows that chorus size (i.e., the number of calling frogs) has a positive effect on call number, inter-call intervals, and chorus duration. We speculate that a competition in a large chorus encourages the male frogs to make their call properties more attractive to conspecific females.
31
Le, Diem Kieu, Thi Anh Thu Dang e Quoc Nguyen Pham. "Production techniques and environmental management in frog farming in Dong Thap province". Dong Thap University Journal of Science 12, n. 5 (24 giugno 2023): 71–77. http://dx.doi.org/10.52714/dthu.12.5.2023.1074.
Testo completoAbstract (sommario):
This study surveyed 40 farmers on their production techniques and environmental management in frog farming in Cao Lanh and Thap Muoi district, Dong Thap province, and the results showed that frogs were cultured in tarpaulin tanks (82.5%), hapas in an earth pond (35%), and earth ponds (2.5%). Most of the farmers (82.5%) had a combination of breeding frogs and production frogs to be self-sufficient froglet. Stocking density is high with 146.3±92.3 individuals/m2 for production frogs and 51.6±35.7 individuals/m2 for breeding frogs. The culture duration of froglet was an average of 33.6±8.8 days/crop (9.3±2.4 crops/year) and production frogs was 64.7±9.7 days/crop (5.1±0.6 crops/year). Frogs were raised with a commercial pellet feed of many brands. The diseases occurred in tadpole and froglet phase (2-30 days), including septicemia diseases (57.5%), red thighs (45%), white bodies (35%), blindness (35%), digestive disorders (20%), and flatulence (15%). The disease causes were mainly due to poor water quality, weather change, feed, and high stocking density. However, few farmers had treated farming system (37.5%), supplemental water (27.5%), and monitored and controlled water quality. There were 60% of households to discharge wastewater directly into rivers and canals. Some farmers have used nutrient for wastewater from frogs with combining frog with fish (27.5%), or discharging wastewater into ditches gardens, fields (7.5%), settling pond (5%), which have helped to increase income and protect the environment. Therefore, farmers need to be supported with knowledge of farming technique and environmental management from the local government.
32
Withers, Philip C. "Evaporative water loss and the role of cocoon formation in Australian frogs". Australian Journal of Zoology 46, n. 5 (1998): 405. http://dx.doi.org/10.1071/zo98013.
Testo completoAbstract (sommario):
Measurements of evaporative water loss (EWL; mg min-1) and resistance (R; sec cm-1) for various Australian frogs indicate three general allometric patterns: non-cocooned and non-‘waterproof’ frogs with EWL ∝ Mass0.30 and R independent of body mass at about 1–3 sec cm-1, cocooned frogs with EWL reduced about 50–200-fold and R about 50–200 sec cm-1, and ‘waterproof’ frogs with EWL reduced about 5–100- fold and R about 5–100 sec cm-1. Cocooned frogs have an exponential reduction in EWL and fairly linear increase in R over time, corresponding to the temporal addition of layers to the cocoon. The biophysical properties of cocoon are generally similar for various species, although there is some variation in both resistance per thickness (5–20 × 104 s cm-2) and diffusion coefficient (0.4–2.4 × 10 –5 cm2 s-1). The hygroscopic property of frog cocoon resembles that of mammalian stratum corneum, hair and wool, and mucopolysaccharides; there is a slight increase in water content of cocoon over a wide range of humidities but a very steep increase in water content and substantial hydration and swelling at >96% RH. This extreme hygroscopic behaviour of frog cocoon at very high RH may reflect less polymer cross-linking in frog cocoon and its high digestibility. The prevention of over-hydration of frog cocoon in vivo may be attributed to the restriction of high water content to only very high RH (>96%).
33
Ma, Yunshuang, Anran Yu, Liangliang Zhang e Rongquan Zheng. "Effects of Rice–Frog Co-Cropping on the Soil Microbial Community Structure in Reclaimed Paddy Fields". Biology 13, n. 6 (30 maggio 2024): 396. http://dx.doi.org/10.3390/biology13060396.
Testo completoAbstract (sommario):
Utilizing and improving the productivity of reclaimed land are highly significant for alleviating the problem of food production shortage in China, and the integrated rice–frog farming model can improve soil fertility. However, there are few studies on the use of integrated rice–frog farming technology to improve the fertility of reclaimed land and increase its efficiency in food production. Therefore, this study was conducted to evaluate the effects of the rice–frog co-cropping mode on the soil fertility and microbial diversity of reclaimed land. A rice monoculture group (SF), low-density rice–frog co-cropping group (SD, 5000 frogs/mu, corresponds to 8 frogs/m2), and high-density rice–frog co-cropping group (SG, 10,000 frogs/mu, corresponds to 15 frogs/m2) were established and tested. The contents of total nitrogen, soil organic matter, available potassium, and available phosphorus of the soil in the SG group were significantly higher than those in the SF group (p < 0.05) in the mature stage of rice. Compared with the SF group, the SD and SG groups improved the soil microbial diversity and changed the structure of the microbial community. This study indicates that compared with the rice monoculture mode, the rice–frog co-cropping pattern can improve the soil fertility, as well as microbial diversity, of reclaimed land.
34
Sleigh, Charlotte. "Jan Swammerdam's frogs". Notes and Records of the Royal Society 66, n. 4 (10 ottobre 2012): 373–92. http://dx.doi.org/10.1098/rsnr.2012.0039.
Testo completoAbstract (sommario):
Having discussed insect metamorphosis at length, Jan Swammerdam's Bybel der Natuure (1679/1737) reached its climax with a substantial description of the generation and muscular activity of frogs. This paper explores the rhetorical role of frogs in Swammerdam's ‘great work’, showing how they were the Archimedean point from which he aimed to reorder all of creation—from insects to humans—within one glorious, God-ordained natural history and philosophy. Swammerdam linked insects to frogs through a demonstration that all underwent epigenesis; and frogs were then linked to humans through a demonstration of their identical muscular activity. The success of Swammerdam's strategy required a theological reconstruction of the frog, traditionally an ungodly creature, such that trustworthy knowledge could be obtained from its body. Perhaps surprisingly, this act of theological cleansing is shown to be somewhat prefigured in the distinctly non-experimental natural history of Edward Topsell (1608). The paper also examines Swammerdam's interactions with the mystic Antoinette Bourignon, and his challenges in reconciling a spirituality of meletetics with a material epistemology in natural philosophy. Differences are revealed between the natural analogies given by Swammerdam in his published and unpublished writings, undermining to a certain extent the triumphal insect–frog–human rhetorical structure of the Bybel .
35
Griffin, Christine T. "Oswaldocruzia filiformis (Nematoda: Trichostrongyloidea) in frogs (Rana temporaria) from three locations in Ireland". Journal of Helminthology 63, n. 1 (marzo 1989): 53–62. http://dx.doi.org/10.1017/s0022149x00008737.
Testo completoAbstract (sommario):
ABSTRACTA total of 444 adult frogs (Rana temporaria) were obtained from three sites in the east of Ireland. Oswaldocruzia filiformis was present at all times of the year; overall, 64% of the frogs were infected, with a mean burden of 5 worms/frog. Most of the parasites were in the first half of the small intestine. A single gross lesion associated with a high worm burden is described. Female parasites were more abundant than males. Most parasitic stages of O. filiformis overwintered in hibernating hosts. Seasonal patterns in the levels of parasitization were not discerned. The intensity of infection was significantly greater in female than male frogs at one of the sites. There was little correlation between the size of host and degree of parasitization. None of the 45 frog tadpoles examined harboured O. filiformis. Frogs became infected by August of their first year.
36
Costanzo, Jon P., e Richard E. Lee Jr. "Cryoprotectant production capacity of the freeze-tolerant wood frog, Rana sylvatica". Canadian Journal of Zoology 71, n. 1 (1 gennaio 1993): 71–75. http://dx.doi.org/10.1139/z93-011.
Testo completoAbstract (sommario):
Freezing survival of the wood frog (Rana sylvatica) is enhanced by the synthesis of the cryoprotectant glucose, via liver glycogenolysis. Because the quantity of glucose mobilized during freezing bears significantly on the limit of freeze tolerance, we investigated the relationship between the quantity of liver glycogen and the capacity for cryoprotectant synthesis. We successfully augmented natural levels of liver glycogen by injecting cold-conditioned wood frogs with glucose. Groups of 8 frogs having mean liver glycogen concentrations of 554 ± 57 (SE), 940 ± 57, and 1264 ± 66 μmol/g catabolized 98.7, 83.4, and 52.8%, respectively, of their glycogen reserves during 24 h of freezing to −2.5 °C. Glucose concentrations concomitantly increased, reaching 21 ± 3, 102 ± 23, and 119 ± 14 μmol/g, respectively, in the liver, and 15 ± 3, 42 ± 5, and 61 ± 5 μmol/mL, respectively, in the blood. Because the capacity for cryoprotectant synthesis depends on the amount of liver glycogen, the greatest risk of freezing injury likely occurs during spring, when glycogen reserves are minimal. Non-glucose osmolites were important in the wood frog's cryoprotectant system, especially in frogs having low glycogen levels. Presumably the natural variation in cryoprotectant synthesis capacity among individuals and populations of R. sylvatica chiefly reflects differences in glycogen reserves; however, environmental, physiological, and genetic factors likely are also involved.
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Gardiner, David, A. Ndayibagira, Felix Grün e Bruce Blumberg. "Deformed frogs and environmental retinoids". Pure and Applied Chemistry 75, n. 11-12 (1 gennaio 2003): 2263–73. http://dx.doi.org/10.1351/pac200375112263.
Testo completoAbstract (sommario):
Since the early 1990s, a substantial number of deformed frogs have been observed in North America, particularly in the upper Midwest and Canada. Attempts to understand the etiology of the deformed frog problem have met with limited success to date with nearly as many proposed explanations as research groups working on the problem. Models for the mechanism underlying the development of deformed frogs include parasite/predation, ultraviolet radiation, and chemical exposure. Each model has its strengths and weaknesses. Despite contentious debate among researchers, there is an overall consensus that the increasing prevalence of deformed frogs is the result of a water-borne contaminant that has recently appeared, or reached a critical concentration. Our detailed analysis of malformed frogs collected in Minnesota ponds and lakes suggested that limb patterning was being modified by the disruption of a retinoid-sensitive developmental signaling pathway. Accordingly, we focused in the identification and characterization of bioactive retinoids from lake water and showed that retinoid treatment of frog embryos at sensitive times of development could recapitulate the full spectrum of limb abnormalities observed in field specimens in the laboratory. These data have led to the conclusion that inappropriate modulation of retinoid signaling by environmental contaminants is the mechanism underlying the increased incidence of frog malformations.
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Miura, Ikuo, Vladimir Vershinin, Svetlana Vershinina, Andrei Lebedinskii, Alexander Trofimov, Ivan Sitnikov e Michihiko Ito. "Hybridogenesis in the Water Frogs from Western Russian Territory: Intrapopulation Variation in Genome Elimination". Genes 12, n. 2 (8 febbraio 2021): 244. http://dx.doi.org/10.3390/genes12020244.
Testo completoAbstract (sommario):
Hybridogenesis in an interspecific hybrid frog is a coupling mechanism in the gametogenic cell line that eliminates the genome of one parental species with endoduplication of the remaining genome of the other parental species. It has been intensively investigated in the edible frog Pelophylax kl. esculentus (RL), a natural hybrid between the marsh frog P. ridibundus (RR) and the pool frog P. lessonae (LL). However, the genetic mechanisms involved remain unclear. Here, we investigated the water frogs in the western Russian territory. In three of the four populations, we genetically identified 16 RL frogs living sympatrically with the parental LL species, or with both parental species. In addition, two populations contained genome introgression with another species, P. bedriagae (BB) (a close relative of RR). In the gonads of 13 RL frogs, the L genome was eliminated, producing gametes of R (or R combined with the B genome). In sharp contrast, one RL male eliminated the L or R genome, producing both R and L sperm. We detected a variation in genome elimination within a population. Based on the genetic backgrounds of RL frogs, we hypothesize that the introgression of the B genome resulted in the change in choosing a genome to be eliminated.
39
Rocha, Carlos F. D., Davor Vrcibradic, Mara C. Kiefer, Carla C. Siqueira, Mauricio Almeida-Gomes, Vitor N. T. Borges Júnior, Fábio H. Hatano et al. "Parameters from the community of leaf-litter frogs from Estação Ecológica Estadual Paraíso, Guapimirim, Rio de Janeiro State, southeastern Brazil". Anais da Academia Brasileira de Ciências 83, n. 4 (30 settembre 2011): 1259–68. http://dx.doi.org/10.1590/s0001-37652011005000036.
Testo completoAbstract (sommario):
We studied the leaf-litter frog community of Estação Ecológica Estadual Paraíso, in Guapimirim, Rio de Janeiro State, southeastern Brazil. Herein we combined three sampling methods (large plots, visual encounter surveys and pit-fall traps) to present data on species composition, richness, relative abundance and densities. The local assemblage of frogs associated to the leaf-litter was composed by 14 species, belonging to nine families. Haddadus binotatus, a direct-developing frog, was the most abundant species in the community. The estimated density of the local leaf-litter frog assemblage based on plot sampling was 4.3 frogs/100 m². Haddadus binotatus had the highest density (1.1 ind/100 m²). Frogs were predominantly found at night. Thoropa miliaris had the largest values of SVL (39.0 ± 10.3 mm), whereas the smallest species were Euparkerella brasiliensis (16.7 ± 2.2 mm) and E. cochranae (16.0 ± 2.7 mm). Rhinella ornata had the highest mean body mass (12.1 ± 7.5 g), and E. cochranae the lowest (0.4 ± 0.2 g). The overall frog mass was 938.6 g/ha. Our data support that higher densities of leaf-litter frogs tend to occur in the Neotropical region compared to the OldWorld tropics, tending to be higher in Central America than in South America.
40
DeMarchi, Joseph A., Andrew Britton, Kaylee O'Donnell e Ralph A. Saporito. "Behavioural preference for low levels of UV-B radiation in two neotropical frog species from Costa Rica". Journal of Tropical Ecology 34, n. 5 (6 agosto 2018): 336–40. http://dx.doi.org/10.1017/s0266467418000287.
Testo completoAbstract (sommario):
Abstract:Tropical frogs experience damaging effects from exposure to UV-B radiation, and some diurnally active, conspicuous species exhibit avoidance behaviours to high levels of UV-B. To determine if similar behaviours are present in other diurnal frogs, we experimentally compared UV-B avoidance in two common species of neotropical diurnal frogs – Oophaga pumilio, an aposematic poison frog and Craugastor bransfordii, a cryptic leaf-litter frog – in response to different levels of UV-B. Wild-caught frogs were tested in experimental arenas fitted with filters that permitted two different levels of UV-B (low: 14% vs. high: 84% UV-B). Both species spent significantly more time under the low UV-B filter, suggesting that behavioural preferences for lower levels of UV-B are common to different diurnal species. Furthermore, male O. pumilio significantly preferred lower levels of UV-B, whereas females did not exhibit a preference for lower UV-B, which may suggest differences in UV-B exposure or sensitivity and/or alternative mechanism(s) to avoid UV-B between sexes. Although limited in scope, the findings of our study suggest that UV-B avoidance may be a behavioural adaptation common to all diurnal frogs.
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Matsuda, Brent M., e John S. Richardson. "Movement patterns and relative abundance of coastal tailed frogs in clearcuts and mature forest stands". Canadian Journal of Forest Research 35, n. 5 (1 maggio 2005): 1131–38. http://dx.doi.org/10.1139/x05-042.
Testo completoAbstract (sommario):
Age-specific movements, abundance, and capture rates of coastal tailed frogs (Ascaphus truei Stejneger) were compared between clearcuts and mature forests in southwestern British Columbia, Canada, during 1998 and 1999 using pitfall traps and drift-fence arrays. Total frog abundance was similar in both habitat types. More adults were caught in mature stands than in clearcuts, but there was no significant difference for immatures. Analysis of numbers of frogs captured indicated that the direction of movement did not differ between habitat types for any age-class. Frogs were captured at similar frequencies across distance from stream in both habitats. These findings suggest that there are age-specific differences in tailed frog abundance in clearcuts along streams without riparian reserves relative to mature forests. Variation among sites had a greater influence than habitat type on the number of immatures. Low proportions of adults in clearcuts suggested that immatures may be transient or that they incurred high rates of mortality. Age-specific differences in habitat use by tailed frogs indicated that total numbers alone are insufficient to determine the effect of forest management on habitat suitability for tailed frogs.
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Ota, Kaiichiro, Ikkyu Aihara e Toshio Aoyagi. "Interaction mechanisms quantified from dynamical features of frog choruses". Royal Society Open Science 7, n. 3 (marzo 2020): 191693. http://dx.doi.org/10.1098/rsos.191693.
Testo completoAbstract (sommario):
We employ a mathematical model (a phase oscillator model) to describe the deterministic and stochastic features of frog choruses in which male frogs attempt to avoid call overlaps. The mathematical model with a general interaction term is identified using a Bayesian approach, and it qualitatively reproduces the stationary and dynamical features of the empirical data. In addition, we quantify the magnitude of attention paid among the male frogs from the identified model, and then analyse the relationship between attention and behavioural parameters using a statistical approach. Our analysis demonstrates a negative correlation between attention and inter-frog distance, and also suggests a behavioural strategy in which male frogs selectively attend to a less attractive male frog (i.e. a male producing calls at longer intervals) in order to more effectively advertise their superior relative attractiveness to females.
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FLANIGAN, JAMES E., PHILIP C. WITHERS e MICHAEL GUPPY. "In Vitro Metabolic Depression of Tissues from the Aestivating Frog Neobatrachus Pelobatoides". Journal of Experimental Biology 161, n. 1 (1 novembre 1991): 273–83. http://dx.doi.org/10.1242/jeb.161.1.273.
Testo completoAbstract (sommario):
The desert frog Neobatrachus pelobatoides reduced its resting metabolism in vivo by 60–70% during 5–7 weeks of aestivation (summer dormancy). The rate ofoxygen consumption (V·OO2) of isolated and intact skeletal muscle, measured in vitro, was 70% lower for aestivating frogs compared with non-aestivating frogs. The cause of the reduced V·OO2 of aestivating frog muscle must lie in the tissue itself rather than being induced by external factors such as oxygen supply or bloodborne metabolites (because these were identical in the in vitro assay conditions), by any short-term effects produced by hormones (as these would have been washed out of the tissues during incubation) or by tissue dehydration (as the tissues from aestivating frogs had rehydrated to non-aestivating levels). The reduced in vitro muscle V·OO2 accounted for 60–77% of the frogs in vivo metabolic depression that accompanied aestivation. Other tissues of the aestivating frog, namely intestine, liver, skin and fat, did not have a reduced in vitro V·OO2. We suggest that metabolic depression is initiated by reduced energy demand in cells and this consequently leads to reduced energy production.
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Matich, Philip, e Christopher M. Schalk. "Move it or lose it: interspecific variation in risk response of pond-breeding anurans". PeerJ 7 (7 giugno 2019): e6956. http://dx.doi.org/10.7717/peerj.6956.
Testo completoAbstract (sommario):
Changes in behavior are often the proximate response of animals to human disturbance, with variability in tolerance levels leading some species to exhibit striking shifts in life history, fitness, and/or survival. Thus, elucidating the effects of disturbance on animal behavior, and how this varies among taxonomically similar species with inherently different behaviors and life histories is of value for management and conservation. We evaluated the risk response of three anuran species—southern leopard frog (Lithobates sphenocephalus), Blanchard’s cricket frog (Acris blanchardi), and green tree frog (Hyla cinerea)—to determine how differences in microhabitat use (arboreal vs ground-dwelling) and body size (small vs medium) may play a role in response to a potential threat within a human-altered subtropical forest. Each species responded to risk with both flight and freeze behaviors, however, behaviors were species- and context-specific. As distance to cover increased, southern leopard frogs increased freezing behavior, green tree frogs decreased freezing behavior, and Blanchard’s cricket frogs increased flight response. The propensity of green tree frogs to use the canopy of vegetation as refugia, and the small body size of Blanchard’s cricket frogs likely led to greater flight response as distance to cover increased, whereas innate reliance on camouflage among southern leopard frogs may place them at greater risk to landscaping, agricultural, and transportation practices in open terrain. As such, arboreal and small-bodied species may inherently be better suited in human altered-landscapes compared to larger, ground-dwelling species. As land-use change continues to modify habitats, understanding how species respond to changes in their environment continues to be of importance, particularly in ecosystems where human-wildlife interactions are expected to increase in frequency.
45
Alkaya, Ahmet, e Hülya Şereflişan. "Histological Comparison of the Edible Water Frog (Pelophylax ridibundus Pallas, 1771) Gonads Before and After Reproduction". Turkish Journal of Agriculture - Food Science and Technology 9, n. 12 (24 dicembre 2021): 2153–58. http://dx.doi.org/10.24925/turjaf.v9i12.2153-2158.4371.
Testo completoAbstract (sommario):
In this study, testicular and ovarian structures of economically important edible Pelophylax ridibundus (Pallas, 1771) were histologically examined before and after reproduction in male and female individuals. Fourty eight (24 ♀, 24 ♂) adult frogs were collected from Gölbaşı Lake in Hatay. The average weight and length values of female frogs collected from nature were found to be 56.61±19.59 g and 79.54±7.07 mm; while, the average weight and length values of male frogs were 36.63±12.84 g and 69.29±9.15 mm, respectively. Frogs were brought to the frog farm established in Aydıncık and placed in breeding ponds with a width of 1m2. Frogs in the ponds were brought to the laboratory of Iskenderun Technical University in different periods, before breeding (March) and after breeding (June). Then, histological samples were taken from ovary and testis. The female frogs were determined ready for reproduction. Moreover, a large number of mature oocytes in the before breeding ovaries in vitellogenic stage, while after reproduction oocytes in primary structure and oocytes which have atresia status observed. Also, increase in the thickness of the theca layer was determined. In the male frog seminiferous tubules containing a large number of spermatogonia, spermatocyte, spermatid and a small number of spermatozoons including sperm bundles and leydig cells were found before reproduction. After the reproduciton, the density of spermatogonia, spermatocyte and spermatids were decreased; while, the density of spermatozoon and sperm bundle were increased in the seminiferous tubules. This study will contribute to the determination of mating and spawning in frog breeding by revealing the histological status of the gonad structure of P. ridibundus in the breeding process.
46
Costanzo, Jon P., M. Clara F. do Amaral, Andrew J. Rosendale e Richard E. Lee. "Seasonality of Freeze Tolerance in a Subarctic Population of the Wood Frog,Rana sylvatica". International Journal of Zoology 2014 (2014): 1–13. http://dx.doi.org/10.1155/2014/750153.
Testo completoAbstract (sommario):
We compared physiological characteristics and responses to experimental freezing and thawing in winter and spring samples of the wood frog,Rana sylvatica, indigenous to Interior Alaska, USA. Whereas winter frogs can survive freezing at temperatures at least as low as −16°C, the lower limit of tolerance for spring frogs was between −2.5°C and −5°C. Spring frogs had comparatively low levels of the urea in blood plasma, liver, heart, brain, and skeletal muscle, as well as a smaller hepatic reserve of glycogen, which is converted to glucose after freezing begins. Consequently, following freezing (−2.5°C, 48 h) tissue concentrations of these cryoprotective osmolytes were 44–88% lower than those measured in winter frogs. Spring frogs formed much more ice and incurred extensive cryohemolysis and lactate accrual, indicating that they had suffered marked cell damage and hypoxic stress during freezing. Multiple, interactive stresses, in addition to diminished cryoprotectant levels, contribute to the reduced capacity for freeze tolerance in posthibernal frogs.
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Hamer, Rowena, Francis L. Lemckert e Peter B. Banks. "Adult frogs are sensitive to the predation risks of olfactory communication". Biology Letters 7, n. 3 (12 gennaio 2011): 361–63. http://dx.doi.org/10.1098/rsbl.2010.1127.
Testo completoAbstract (sommario):
Olfaction is a common sensory mode of communication in much of the Vertebrata, although its use by adult frogs remains poorly studied. Being part of an open signalling system, odour cues can be exploited by ‘eavesdropping’ predators that hunt by smell, making association with odour a high-risk behaviour for prey. Here, we show that adult great barred frogs ( Mixophes fasciolatus ) are highly attracted to odour cues of conspecifics and those of sympatric striped marsh frogs ( Limnodynastes peronii ). This attraction decreased significantly with the addition of odours of a scent-hunting predator, the red-bellied black snake ( Pseudechis porphyriacus ), indicating that frogs perceived predation risks from associating with frog odours. Male frogs, however, maintained some attraction to unfamiliar conspecific scents even with predator odours present, suggesting that they perceived benefits of odour communication despite the risk. Our results indicate that adult frogs can identify species and individuals from their odours and assess the associated predation risk, revealing a complexity in olfactory communication previously unknown in adult anurans.
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Courtois, Daniel, Raymond Leclair jr., Sylvain Lacasse e Pierre Magnan. "Habitats préférentiels d'amphibiens ranidés dans des lacs oligotrophes du Bouclier laurentien, Québec". Canadian Journal of Zoology 73, n. 9 (1 settembre 1995): 1744–53. http://dx.doi.org/10.1139/z95-206.
Testo completoAbstract (sommario):
From a study of riparian habitat structure and a quantitive distribution survey of bullfrog, Rana catesbeiana, mink frog, Rana septentrionalis, and green frog, Rana clamitans melanota, in 31 oligotrophic lakes, we looked for, among 18 physiographic parameters, those that could best explain the spatial organisation of the ranid community. The three species cohabitated in 18 lakes, the mink frog and the green frog in 10 lakes without bullfrog, and the bullfrog alone in 3 lakes. These frogs preferentially occupied (i) habitats with medium or high density of emergent vegetation, (ii) areas with extensive floating aquatic vegetation, (iii) muddy and silty areas, and (iv) especially for the green frog, shrubby habitats with ericaceae. Substrates had a poor explicative value. In lakes devoid of bullfrogs, the mink frogs and green frogs were more frequently abundant and showed a more even distribution in the different habitats than when they were sympatric with bullfrogs. A Spearman's rank correlation analysis confirmed the similarity of habitat preferences between the three species and the poor capacity of the habitat structure to predict the ranid community composition.
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Wendel, Emily, Amulya Yaparla, Mattie Melnyk, Daphne Koubourli e Leon Grayfer. "Amphibian (Xenopus laevis) Tadpoles and Adult Frogs Differ in Their Use of Expanded Repertoires of Type I and Type III Interferon Cytokines". Viruses 10, n. 7 (17 luglio 2018): 372. http://dx.doi.org/10.3390/v10070372.
Testo completoAbstract (sommario):
While amphibians around the globe are facing catastrophic declines, in part because of infections with pathogens such as the Frog Virus 3 (FV3) ranavirus; the mechanisms governing amphibian susceptibility and resistance to such pathogens remain poorly understood. The type I and type III interferon (IFN) cytokines represent a cornerstone of vertebrate antiviral immunity, while our recent work indicates that tadpoles and adult frogs of the amphibian Xenopus laevis may differ in their IFN responses to FV3. In this respect, it is notable that anuran (frogs and toads) tadpoles are significantly more susceptible to FV3 than adult frogs, and thus, gaining greater insight into the differences in the tadpole and adult frog antiviral immunity would be invaluable. Accordingly, we examined the FV3-elicited expression of a panel of type I and type III IFN genes in the skin (site of FV3 infection) and kidney (principal FV3 target) tissues and isolated cells of X. laevis tadpoles and adult frogs. We also examined the consequence of tadpole and adult frog skin and kidney cell stimulation with hallmark pathogen-associated molecular patterns (PAMPs) on the IFN responses of these cells. Together, our findings indicate that tadpoles and adult frogs mount drastically distinct IFN responses to FV3 as well as to viral and non-viral PAMPs, while these expression differences do not appear to be the result of a distinct pattern recognition receptor expression by tadpoles and adults.
50
Narayan, Edward, Frank Molinia, Ketan Christi, Craig Morley e John Cockrem. "Urinary corticosterone metabolite responses to capture, and annual patterns of urinary corticosterone in wild and captive endangered Fijian ground frogs (Platymantis vitiana)". Australian Journal of Zoology 58, n. 3 (2010): 189. http://dx.doi.org/10.1071/zo10010.
Testo completoAbstract (sommario):
This study was based on the development of a non-invasive glucocorticoid enzyme-immunoassay for the assessment of stress in wild and captive endangered Fijian ground frogs (Platymantis vitiana). Enzyme-immunoassays were developed and validated for the first time to non-invasively measure both cortisol and corticosterone metabolites in frog urine. Frog urine showed parallel displacement with corticosterone but not cortisol standards, therefore corticosterone enzyme immunoassays were used to examine stress in wild and captive frogs. Urinary corticosterone metabolite concentrations increased in frog urine (n = 4) at 6 h, 1 day and 2 days after injection with adrenocorticotropic hormone (0.44 μg g–1 bodyweight), indicating that the corticosterone enzyme-immunoassay could detect changes in circulating corticosterone in frogs. Urinary concentrations of corticosterone were measured in wild frogs (n = 18) after capture in the field. The first measurement beyond the initial sample was at 2–3 h. Mean urinary corticosterone concentrations rose after the initial sample and were significantly elevated in samples collected 3–4 h after capture. This is the first demonstration of a urinary corticosterone response to capture in amphibians. Urinary corticosterone metabolite concentrations for all months combined were lower in captive males than in wild males, and differed between vitellogenic, non-vitellogenic and captive females. Concentrations did not differ between captive and wild females. In conclusion, urinary corticosterone enzyme immunoassays can be used in frogs for assessing stress responses to capture and natural stress profiles of both captive and wild populations.