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1
Youson, J. H., J. A. Holmes, J. A. Guchardi, J. G. Seelye, R. E. Beaver, J. E. Gersmehl, S. A. Sower i F. W. H. Beamish. "Importance of Condition Factor and the Influence of Water Temperature and Photoperiod on Metamorphosis of Sea Lamprey Petromyzon marinus". Canadian Journal of Fisheries and Aquatic Sciences 50, nr 11 (1.11.1993): 2448–56. http://dx.doi.org/10.1139/f93-269.
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The incidence of metamorphosis of larval sea lamprey, Petromyzon marinus, was strongly affected by water temperature but not photoperiod. In a 1991 experiment, the development of metamorphosing animals in 13 °C water was retarded about 1 mo relative to animals metamorphosing at 21 °C and to a population from the Chippewa River, Michigan; the minimum length, weight, and condition factor (CF) of metamorphosing experimental animals were 117 mm, 2.8 g, and 1.50, respectively, and only 4% metamorphosed at 13 °C and 18.9% at 21 °C. In 1992, with a population from the Great Chazy River, New York, 66% of the animals at 13 °C and 84% at 21 °C metamorphosed. The higher incidence of metamorphosis in 1992 is partly related to the use of larvae that were larger than the minima established in 1991. We predicted, using criteria defined below, that 74 and 72% of the animals at 13 and 21 °C, respectively, would metamorphose. Our predictions were consistent with observations at 13 °C and for five of seven replicate tanks at 21 °C. We suggest that a presumptive metamorphosing sea lamprey in landlocked populations should be at least 120 mm long, weigh 3.0 g, and have a CF ≥ 1.50 and that these criteria must be used in conjunction.
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Holmes, J. A., F. W. H. Beamish, J. G. Seelye, S. A. Sower i J. H. Youson. "Long-term Influence of Water Temperature, Photoperiod, and Food Deprivation on Metamorphosis of Sea Lamprey, Petromyzon marinus". Canadian Journal of Fisheries and Aquatic Sciences 51, nr 9 (1.09.1994): 2045–51. http://dx.doi.org/10.1139/f94-207.
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After 11 mo in the laboratory, significantly more sea lamprey, Petromyzon marinus, larvae from the Chippewa River, Michigan, metamorphosed in an ambient temperature regime (3 ± 2 animals∙tank−1) compared with a fixed 21 °C temperature (0 animals); photoperiod and food deprivation did not have detectable effects on the incidence of metamorphosis. Metamorphosing animals in our laboratory study were significantly smaller in size (length and weight) and had a lower condition factor (CF) than animals from the same population that metamorphosed a year earlier under field and shorter term laboratory conditions. We also predicted, using criteria of 120 mm, 3.0 g, and a CF of 1.50, that 12 and 14% of the animals in the ambient and fixed temperature regimes, respectively, would metamorphose. Our prediction for the ambient temperature did not differ significantly from observed (11%). We suggest that larvae in landlocked populations of sea lamprey that are at least 120 mm long, weigh 3.0 g, and have a CF of 1.50 or greater in the fall can be predicted to metamorphose the following summer. Furthermore, our data show that low temperature during the winter followed by rising temperature in the spring is the primary environmental cue initiating metamorphosis in sea lamprey.
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Holmes, John A., Helen Chu, Syeda A. Khanam, Richard G. Manzon i John H. Youson. "Spontaneous and induced metamorphosis in the American brook lamprey, Lampetra appendix". Canadian Journal of Zoology 77, nr 6 (10.10.1999): 959–71. http://dx.doi.org/10.1139/z99-056.
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We described the seven stages of spontaneous metamorphosis in the American brook lamprey (Lampetra appendix) and assessed the importance of size as a determinant of spontaneous and induced metamorphosis. Serum concentrations of the thyroid hormones (TH) thyroxine (T4) and triiodothyronine (T3) were measured in metamorphosing and nonmetamorphosing L. appendix. The sequence of stages in metamorphosis and changes in the relative lengths of most body regions were consistent with data reported for other lamprey species. However, premetamorphic and metamorphosing L. appendix in the early stages of metamorphosis (1-3) were much larger in size (at least 155 mm and 5.40 g) than has been observed for other lamprey species. Serum concentrations of T4 and T3 were high by the end of the larval period and declined significantly by stage 2 of metamorphosis. Larvae greater than or equal to 130 mm in length were treated with either potassium perchlorate (KClO4; 0.01 and 0.05%) or 10 mg/L propylthiouracil (PTU; 0.0001%) for 117 days from September to January to determine if metamorphosis could be induced by these goitrogens. Both concentrations of KClO4 successfully induced metamorphosis in L. appendix, but the incidence of metamorphosis (62%) was much lower than reported in sea lampreys (98%) of comparable size. Serum concentrations of T4 and T3 declined by 64-76 and 93-96% relative to control values, respectively, in metamorphosing and nonmetamorphosing L. appendix treated with KClO4. PTU elicited declines of 55% for T4 and 80% for T3, but only one animal metamorphosed. Based on these data, we conclude that a decline in serum TH levels is necessary for metamorphosis in L. appendix, but not sufficient by itself to trigger the process.
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Pronych, Scott, i Richard Wassersug. "Lung use and development in Xenopus laevis tadpoles". Canadian Journal of Zoology 72, nr 4 (1.04.1994): 738–43. http://dx.doi.org/10.1139/z94-099.
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Shortly after hatching, Xenopus laevis tadpoles fill their lungs with air. We examined the role played by early lung use in these organisms, since they are able to respire with both their lungs and their gills. We investigated the effect on X. laevis development when the larvae were prevented from inflating their lungs, and whether early lung use influenced the size of the lungs or the tadpole's ability to metamorphose. Tadpoles that were denied access to air had lungs one-half the size of those of controls. This difference in lung size was too large to be explained merely by a stretching of the lung due to inflation. The longer tadpoles were denied access to air, the longer they took to metamorphose, and their probability of completing metamorphosis diminished. One tadpole raised throughout its larval life without access to air successfully metamorphosed but had abnormal, solidified lungs and an enlarged heart. Collectively, these experiments demonstrate that early lung use in tadpoles is important in determining both ultimate lung size and the probability of successfully metamorphosing. Lung use during early larval development in X. laevis is not absolutely necessary for survival through metamorphosis, but its absence severely handicaps growth.
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Iwai, Noriko, i Kiyomi Yasumiba. "Field variations in mass at metamorphosis in a stream frog, Odorrana splendida, and their relationship with the stream environment". Animal Biology 71, nr 3 (3.09.2021): 297–310. http://dx.doi.org/10.1163/15707563-bja10053.
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Abstract Animals with complex life cycles, such as amphibians, shift their habitats when they metamorphose. Metamorphosing traits (e.g., size at, and timing of, metamorphosis) at an early stage can affect the growth, reproduction, and survival in the adult stage. Thus, metamorphosing traits are important factors that affect the fitness of the individuals. Although size at metamorphosis in the field has been investigated in amphibians, its relationship with environmental factors has been scarce. We aimed to quantify variations in the mass at metamorphosis of a stream frog, Odorrana splendida, among multiple streams, and show the relationship of these variations with environmental conditions. We searched for metamorphs in 11 field streams and measured their body size. We then examined the relationship between environmental conditions of each stream and the mass at metamorphosis to reveal the factors determining the mass. We found 229 metamorphs over three years. The estimated mass at metamorphosis ranged from 0.17 g to 1.44 g, with a coefficient of variation among streams of 0.38. The size at metamorphosis significantly differed among streams, and was found to be positively affected by water temperature and chlorophyll a concentration, and negatively affected by altitude, slope gradient, and the number of adult calls. We showed that O. splendida has a large variation in mass at metamorphosis within and among natural streams. A lower mass at metamorphosis may correlate with scarce food resources in the stream and higher competition during the larval stages, resulting from a higher number of mating adults.
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Byrne, Isabel, Robyn Thomson, Rory Thomson, Duncan Murray-Uren i J. Roger Downie. "Observations on metamorphosing tadpoles of Hyalinobatrachium orientale (Anura: Centrolenidae)". Phyllomedusa: Journal of Herpetology 19, nr 2 (12.12.2020): 217–23. http://dx.doi.org/10.11606/issn.2316-9079.v19i2p217-223.
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Observations on metamorphosing tadpoles of Hyalinobatrachium orientale (Anura: Centrolenidae). Metamorphosis, when anuran amphibians resorb their tails and remodel their mouthparts and internal organs, is a vulnerable stage in the frog’s life history. As larvae metamorphose from tadpoles to adult frogs, they are neither suited to aquatic life nor ready for active terrestrial life. Previous studies have examined the duration of metamorphosis in a range of species, with respect to tadpole size, habitat, and other factors; however, the duration of metamorphosis relative to where it takes place has not been reported in centrolenids. In Hyalinobatrachium orientale, metamorphosis takes place on the upper surfaces of the leaves of low understory plants and lasts 3.5–4.0 days, a little longer than expected for the tadpole of this body size. Metamorphs seem to shift their perches from leaf to leaf randomly. There are no significant differences in the temperature or relative humidity of the upper and lower surfaces of leaves in the forest understory; thus, the presence of the metamorphs on the upper surfaces of leaves may provide moisture from the upper story vegetation after rain and protect them from terrestrial predators.
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Chelgren, Nathan D., Daniel K. Rosenberg, Selina S. Heppell i Alix I. Gitelman. "Individual variation affects departure rate from the natal pond in an ephemeral pond-breeding anuran". Canadian Journal of Zoology 86, nr 4 (kwiecień 2008): 260–67. http://dx.doi.org/10.1139/z08-003.
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Frogs exhibit extreme plasticity and individual variation in growth and behavior during metamorphosis, driven by interactions of intrinsic state factors and extrinsic environmental factors. In northern red-legged frogs ( Rana aurora Baird and Girard, 1852), we studied the timing of departure from the natal pond as it relates to date and size of individuals at metamorphosis in the context of environmental uncertainty. To affect body size at metamorphosis, we manipulated food availability during the larval stage for a sample (317) of 1045 uniquely marked individuals and released them at their natal ponds as newly metamorphosed frogs. We recaptured 34% of marked frogs in pitfall traps as they departed and related the timing of their initial terrestrial movements to individual properties using a time-to-event model. Median age at first capture was 4 and 9 days postmetamorphosis at two sites. The rate of departure was positively related to body size and to date of metamorphosis. Departure rate was strongly negatively related to time elapsed since rainfall, and this effect was diminished for smaller and later metamorphosing frogs. Individual variation in metamorphic traits thus affects individuals’ responses to environmental variability, supporting a behavioral link with variation in survival associated with these same metamorphic traits.
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Chambers, R. Christopher, i William C. Leggett. "Size and Age at Metamorphosis in Marine Fishes: An Analysis of Laboratory-Reared Winter Flounder (Pseudopleutonectes americanus) with a Review of Variation in Other Species". Canadian Journal of Fisheries and Aquatic Sciences 44, nr 11 (1.11.1987): 1936–47. http://dx.doi.org/10.1139/f87-238.
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Offspring of adult winter flounder (Pseudopleuronectes americanus) collected from Conception Bay, Newfoundland, were reared from fertilization to metamorphosis. We tested two hypotheses: 1) length and age at metamorphosis are equally variable among individuals and (2) length and age at metamorphosis are not correlated. Length at metamorphosis was significantly less variable than age at metamorphosis when data from all laboratory populations were pooled and in 15 of 18 populations. Coefficients of variation for length and age at metamorphosis for the pooled data were 0.051 and 0.123, respectively. Length and age at metamorphosis were positively correlated when the data were pooled (r = 0.42, p < 0.001) and within 8 of 18 populations. Larvae that metamorphose late do so at larger sizes. When length and age at metamorphosis were converted to growth and developmental rates for the full larval period, significant positive correlations were evident between these rates for the pooled data (r = 0.68, p < 0.001) and within 16 of 18 populations. Larvae that grow slowly, therefore, remain as larvae longer. An examination of published values on size and age at metamorphosis in marine fishes revealed a pattern consistent with our findings both within and among populations and environments: (1) variation in length was less than variation in age at metamorphosis and (2) positive correlations between growth and developmental rates were evident through the larval period. Increased size at metamorphosis may ameliorate competitive effects and reduce the risk of predation in the period immediately following metamorphosis. Due to the considerable variation in the duration of the larval period (age at metamorphosis) the number of individuals that successfully metamorphose and subsequently enter the mature population could be significantly altered under differing environmental conditions.
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Rao, Xiaozhen, i Gang Lin. "Effects of age, salinity and temperature on the metamorphosis and survival of Capitulum mitella cyprids (Cirripedia: Thoracica: Scalpellomorpha)". Journal of the Marine Biological Association of the United Kingdom 100, nr 1 (14.01.2020): 55–62. http://dx.doi.org/10.1017/s0025315419001152.
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AbstractCapitulum mitella is a tropical/sub-tropical intertidal barnacle of high economic value. However, no studies have yet focused on the effects of the extrinsic and intrinsic factors that affect the metamorphosis of this species. The current study stored cyprids at room temperature (24–26°C) and low temperature (7°C) and then compared the effects of age and storage temperature on cyprid metamorphosis. The effects of salinity and temperature on cyprid metamorphosis and survival were examined. Results showed the following. (1) Young 0-day cyprids were not competent to metamorphose, and C. mitella cyprids had a pre-competent phase. (2) The cyprid metamorphosis percentage at different storage temperatures with the same age was higher at room temperature than at 7°C. Low temperature storage of cyprids appeared to be unsuitable for C. mitella. The ideal storage time at room temperature for cyprids was 3–5 days. (3) The cyprids could complete metamorphosis at a salinity range of 20–45 mg l−1, and the optimum salinity range for metamorphosis was 25–35 mg l−1. At 15 mg l−1 salinity, the cyprids could survive but failed to metamorphose. (4) The cyprids could survive and complete metamorphosis at 18–36°C, and the optimum temperature range for metamorphosis was 21–33°C. The metamorphosis of C. mitella cyprids can tolerate a wide spectrum of salinity and temperature, which is related to the distribution location, habitat environment and lifestyle. Results of this study may provide a basis for the settlement biology, recruitment ecology and aquaculture of this species.
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Mathiron, Anthony G. E., Jean-Paul Lena, Sarah Baouch i Mathieu Denoël. "The ‘male escape hypothesis’: sex-biased metamorphosis in response to climatic drivers in a facultatively paedomorphic amphibian". Proceedings of the Royal Society B: Biological Sciences 284, nr 1853 (19.04.2017): 20170176. http://dx.doi.org/10.1098/rspb.2017.0176.
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Paedomorphosis is a major evolutionary process that bypasses metamorphosis and allows reproduction in larvae. In newts and salamanders, it can be facultative with paedomorphs retaining gills and metamorphs dispersing. The evolution of these developmental processes is thought to have been driven by the costs and benefits of inhabiting aquatic versus terrestrial habitats. In this context, we aimed at testing the hypothesis that climatic drivers affect phenotypic transition and the difference across sexes because sex-ratio is biased in natural populations. Through a replicated laboratory experiment, we showed that paedomorphic palmate newts ( Lissotriton helveticus ) metamorphosed at a higher frequency when water availability decreased and metamorphosed earlier when temperature increased in these conditions. All responses were sex-biased, and males were more prone to change phenotype than females. Our work shows how climatic variables can affect facultative paedomorphosis and support theoretical models predicting life on land instead of in water. Moreover, because males metamorphose and leave water more often and earlier than females, these results, for the first time, give an experimental explanation for the rarity of male paedomorphosis (the ‘male escape hypothesis’) and suggest the importance of sex in the evolution of paedomorphosis versus metamorphosis.
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DARE, O. K., i M. R. FORBES. "Rates of development in male and female Wood Frogs and patterns of parasitism by lung nematodes". Parasitology 135, nr 3 (9.11.2007): 385–93. http://dx.doi.org/10.1017/s0031182007003836.
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SUMMARYResearchers are becoming interested in testing whether investment in growth and/or development trades off against investment in parasite defence. We tested this idea by examining relations between development of Wood Frogs (Rana sylvatica) and susceptibility to lung nematodes (Rhabdias ranae). Male and female frogs reared in outdoor mesocosms were the same length and mass at metamorphosis. However, males metamorphosed sooner than females. Lung nematodes were no more likely to penetrate male versus female metamorphs following controlled exposures, but males had higher intensities of adult female worms and the largest worms per host were, on average, of larger size in male metamorphs. Males that took longer to metamorphose carried higher numbers of worms in their lungs than males that metamorphosed early. In comparison, females that developed faster harboured more worms in their lungs than females that took longer to reach metamorphosis. Our results suggest that variation in susceptibility to lung nematodes is influenced by host sex and possibly also by sex-specific relations with developmental rate. Further, male hosts might prove to be a more important source of infective stages of worms than female hosts.
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Baird, Andrew H., i Aileen N. C. Morse. "Induction of metamorphosis in larvae of the brooding corals Acropora palifera and Stylophora pistillata". Marine and Freshwater Research 55, nr 5 (2004): 469. http://dx.doi.org/10.1071/mf03121.
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Many coral larvae require surface contact with crustose red algae (CRA) to induce metamorphosis; however, many features of the ecology of pocilloporid corals, such as their ability to colonize primary substrata, suggest that their larvae respond to different cues. We compared the metamorphosis of larvae of the brooding corals Stylophora pistillata (family Pocilloporidae) and Acropora palifera (family Acroporidae) in response to a variety of environmental cues. Acropora palifera metamorphosed only in the presence of three species of CRA. In contrast, S. pistillata metamorphosed in all assays, except those containing the brown alga Lobophora sp. Metamorphosis was highest (80 ± 20%) in unfiltered sea water; however, metamorphosis also occurred in 0.2-μm filtered sea water. These results suggest that S. pistillata larvae respond to both large and small water-borne molecular cues. The lack of a stringent requirement for surface contact with CRA will allow S. pistillata larvae to pre-empt species that require a more developed fouling community to induce metamorphosis and this feature of larval ecology may be the key to understanding the success of many opportunistic benthic species.
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Porter, David H. "Metamorphoses and Metamorphosis: A Brief Response". American Journal of Philology 124, nr 3 (2003): 473–76. http://dx.doi.org/10.1353/ajp.2003.0050.
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Licht, Lawrence E. "The effect of food level on growth rate and frequency of metamorphosis and paedomorphosis in Ambystoma gracile". Canadian Journal of Zoology 70, nr 1 (1.01.1992): 87–93. http://dx.doi.org/10.1139/z92-013.
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The effect of food level on larval growth response and frequency of metamorphosis and paedomorphosis was examined in Ambystoma gracile from high- and low-elevation populations in British Columbia. Larvae that eventually metamorphosed and those that became paedomorphic did not differ in growth rates when fed equal quantities of food. Body size at metamorphosis did not differ between fast- and slow-growing larvae, but larvae fed high levels of food metamorphosed sooner than those fed less. Food level had no effect on the frequency of metamorphosis and paedomorphosis. Larvae of different sexes did not differ in growth rate or frequency of metamorphosis and paedomorphosis, nor did larvae originating from populations from high and low elevations. Variation in the metamorphic response occurred within and between larvae from separate egg clutches. The findings are discussed in light of current hypotheses on factors influencing alternative life-history patterns in facultatively paedomorphic salamanders.
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Doughty, Paul, i J. Dale Roberts. "Plasticity in age and size at metamorphosis of Crinia georgiana tadpoles: responses to variation in food levels and deteriorating conditions during development". Australian Journal of Zoology 51, nr 3 (2003): 271. http://dx.doi.org/10.1071/zo02075.
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Adaptive phenotypic plasticity in life-history traits is predicted to evolve when populations occur in heterogeneous environments. Anuran larvae of many species cannot escape their aquatic environment until metamorphosis and therefore should show plasticity in response to conditions experienced as tadpoles. In this study, we manipulated the aquatic environments of Crinia georgiana tadpoles in the laboratory to mimic variation among ponds in resources and drying conditions in nature. This species breeds in very shallow water in winter and ponds frequently dry between bouts of rain, especially towards spring. Tadpoles kept in constant conditions at different levels of food metamorphosed at different body sizes but showed no plasticity in metamorphic timing. Tadpoles fed only lettuce metamorphosed at sizes similar to those of field-collected tadpoles, whereas tadpoles fed a more protein-rich food metamorphosed at unusually large sizes, indicating that the seeps where C. georgiana tadpoles occur are poor in nutrients. When we decreased food and water levels, tadpoles at later developmental stages were able to accelerate development and metamorphose earlier than tadpoles kept under constant conditions. Furthermore, tadpoles in very shallow water with no access to food metamorphosed earlier and at smaller body sizes than tadpoles with a more moderate decrease in depth that were able to continue feeding. Rapid development and the ability to accelerate metamorphosis in C. georgiana tadpoles are consistent with adaptation in a heterogeneous environment where larvae are under strong time constraints.
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Holmes, John A., i John H. Youson. "Fall condition factor and temperature influence the incidence of metamorphosis in sea lampreys, Petromyzon marinus". Canadian Journal of Zoology 72, nr 6 (1.06.1994): 1134–40. http://dx.doi.org/10.1139/z94-151.
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Larval sea lampreys of immediate premetamorphic size (at least 120 mm and 3.0 g) were subjected to ambient or constant 21 °C temperature regimes for 9 months to investigate the influence of temperature and a fall condition factor (CF) of 1.50 or greater on the incidence of metamorphosis the following summer. The incidence of metamorphosis was 53% in the ambient temperature regime (29/55) and only 2% (1/55) in the constant temperature regime. About 64% (7/11) of the presumptively metamorphic larvae in the ambient temperature regime entered metamorphosis compared with 10% (1/10) in the constant temperature regime. Our predictions of metamorphosis based on CF were consistent with the observation that seven presumptively metamorphic larvae (CF ≥ 1.50) metamorphosed in the ambient temperature regime and that there was no metamorphosis among presumptively nonmetamorphic larvae in the constant temperature regime. Significantly more presumptively nonmetamorphic larvae in the ambient regime entered metamorphosis and fewer presumptively metamorphic larvae (CF < 1.50) metamorphosed in the constant temperature regime than expected. We attribute this response to the effects of temperature on metabolic processes. Larval sea lampreys of the appropriate size (≥ 120 mm and ≥ 3.0 g) with a CF of 1.50 or greater in the fall will usually enter metamorphosis the following July, but the accuracy of these predictions may be improved in some populations by using an empirically determined CF criterion that reflects seasonal or population differences in mass–length relationships.
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Rollins-Smith, Louise A., Patrick J. Blair i A. Tray Davis. "Thymus Ontogeny in Frogs: T-Cell Renewal at Metamorphosis". Developmental Immunology 2, nr 3 (1992): 207–13. http://dx.doi.org/10.1155/1992/26251.
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Metamorphosis in amphibians presents a unique problem for the developing immune system. Because tadpoles are free-living, they need an immune system to protect against potential pathogens. However, at metamorphosis, they acquire a variety of new adultspecific molecules to which the tadpole immune system must become tolerant. We hypothesized thatXenopus laevistadpoles may avoid potentially destructive antiself responses by largely discarding the larval immune system at metamorphosis and acquiring a new one. By implanting triploid (3N) thymuses into diploid (2N) hosts, we examined the influx and expansion of host T-cell precursors in the donor thymus of normally metamorphosing and metamorphosis-inhibited frogs. We observed that donor thymocytes are replaced by host-derived cells during metamorphosis, but inhibition of metamorphosis does not prevent this exchange of cells. The implanted thymuses export T cells to the spleen. This donor-derived pool of cells declines after metamorphosis in normally developing frogs but is retained to a greater extent if metamorphosis is inhibited. These studies confirm previous observations of a metamorphosis-associated wave of expansion of T cells and demonstrate that it is not dependent on the relatively high concentrations of thyroid hormones required for metamorphosis. Although some larval T cells persist through metamorphosis, others may be destroyed or the larval population is significantly diluted by the expanding adult population.
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Lin, Gang, i Xiaozhen Rao. "Metamorphosis of the Pedunculate Barnacle Capitulum mitella Linnaeus, 1758 (Cirripedia: Scalpelliformes)". Journal of the Marine Biological Association of the United Kingdom 97, nr 8 (30.08.2016): 1643–50. http://dx.doi.org/10.1017/s0025315416001089.
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In this paper, metamorphosis of laboratory-reared cyprids of the pedunculate cirripede, Capitulum mitella was successfully induced. A timeline and a detailed description of morphological events during metamorphosis were derived from light microscopy and scanning electron microscopy analyses. The metamorphic process of cyprids involves five main events. (1) Triggering of metamorphosis: after 0–6 h of reagent exposure, the epidermis ventral to the compound eyes gradually invaginates. (2) Invagination and separation of epidermis: after 6–36 h, the invagination bypasses the compound eyes, the cypris epidermis separates slightly from the carapace and the nauplius eye gradually migrates ventrally. (3) Formation of juvenile rudiment: after 36–72 h, the metamorphosing specimen shape slightly resembles that of a juvenile. (4) Shedding of thoracopodal exuvium: after 72–96 h, the cyprid finally sheds the thoracopodal exuvium and metamorphoses into a juvenile barnacle. (5) Early development of juvenile barnacle: the juvenile shed the cirrum cuticle for the first, second, third and fourth time at 1.5–2, 1.5–2, 4–5 and 5–6 days, respectively. The newly formed juvenile completely assumes the shape and armature of all shell-plates found in adult barnacle. Rostro-carnal length of the juvenile is 240–260 μm. Tergum, scutum and upper latus are paired, and carina and rostrum are unpaired. Uniform circular depressions are dispersed on the surface of the tergum, scutum and carina. The rostrum and upper latus, which have the shape of small triangle, are not clear. The entire surface of the peduncle is covered with convoluted cuticular ridges. The metamorphosis of C. mitella is similar to that of Lepas.
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Da Silva Martins, Ana Glaucia, Raoni Rebouças, Isaias Santos, Adão Henrique Rosa Domingos i Luís Felipe Toledo. "Influence of tail injury on the development of Neotropical elegant treefrog tadpoles". Acta Herpetologica 17, nr 1 (28.04.2022): 13–20. http://dx.doi.org/10.36253/a_h-11453.
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Anuran larvae in aquatic environments are important prey items for several vertebrate and invertebrate species. Besides avoiding predation, there are some strategies that may reduce the physical damage in those tadpoles that survive the predation attempt. For example, the injured tadpole tail can regrow after a predator bite, but few studies have examined the consequences of such injury. We examined the consequences of three levels of injury to the tail and how this influenced development and feeding behavior of tadpoles of the Neotropical elegant treefrog, Dendropsophus elegans. We collected spawns and kept them in the laboratory until tadpoles reached Gosner’s stages 28 to 35. Then, they were separated in four experimental groups: individuals with tail trimmed in 30, 50 or 70 % of its length, and a control group, with no tail removing. We counted the days until metamorphosis, calculated the Scaled Mass Index (SMI) through weight and length of newly-metamorphosed, and evaluated the feeding frequency to evaluate the influence of tail amputation on them. We found that the time until metamorphosis was positively related to the extent of the amputation, but SMI and feeding behavior were not influenced. As the time to metamorphose is related to the survivorship chances of individuals: i.e., if the aquatic environment is with high density of predators, it would be advantageous to rapidly metamorphose out of the water. However, tail injury delays the metamorphose process, which could influence the survival of the individual.
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Usmanova, Shoira Rustamovna. "The Application Of The Method Of Metamorphosis In The Folklore Of The Peoples Of The East". Psychology and Education Journal 58, nr 1 (29.01.2021): 1033–42. http://dx.doi.org/10.17762/pae.v58i1.852.
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In recent years, interdisciplinary research, including folklore, ethnography, linguoculturology and other disciplines, has been expanding. The complex study of materials related to various sciences ensures the complementarity of the fields of science, contributes to a deeper and more systematic understanding of the phenomena of language and culture. In particular, the comparative study of the specific motives and methods in the discourse of mythological traditions and fairy tales in folklore texts serves to determine the way of thinking, mentality and imagination of different peoples.
This article is devoted to the study of the phenomenon of metamorphosis, which is reflected in the folklore of the peoples of the East. Metamorphosis is the transformation of any being or thing, form or species into a new, different form and type, as well as an unusual change in something. Metamorphoses rely on the most ancient mythopoetic ideas and reflect their unique characteristics.
The article comparatively studies the application of the method of metamorphosis in the myths, legends, epics and fairy tales of the peoples of the East, the universal and different aspectsof metamorphoses. The types of metamorphoses, their ways of occurrence, causes, factors and peculiarities are also described.
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Sacks, Edward S. "Theater, Performance, and Illusion in Ovid Metamorphoses 11". Illinois Classical Studies 47, nr 1 (1.04.2022): 102–31. http://dx.doi.org/10.5406/23285265.47.1.05.
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Abstract Themes of theater, performance, and illusion course through Metamorphoses 11. The theme of “theater” and its disintegration is established in the opening Orpheus episode and culminates in Ceyx-Alcyone, where Morpheus's self-conscious acting in Alcyone's dream shatters the usual harmony between actor and role. The unveiling of theater is also connected with the unveiling of metamorphosis. This latter disruption, in the Peleus-Thetis episode, involves crucial disclosures about metamorphosis by one metamorphic deity Proteus to defeat the transformations of another (Thetis). These disintegrations are part of connected motifs, wherein art, artist, and metamorphosis are severed into component parts and exposed to view.
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Rahman, M. Aminur, Fatimah Md Yusoff, A. Arshad i Tsuyoshi Uehara. "Effects of Delayed Metamorphosis on Larval Survival, Metamorphosis, and Juvenile Performance of Four Closely Related Species of Tropical Sea Urchins (GenusEchinometra)". Scientific World Journal 2014 (2014): 1–11. http://dx.doi.org/10.1155/2014/918028.
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We report here, the effects of extended competency on larval survival, metamorphosis, and postlarval juvenile growth of four closely related species of tropical sea urchins,Echinometrasp. A (Ea),E. mathaei(Em),Echinometrasp. C (Ec), andE. oblonga(Eo). Planktotrophic larvae of all four species fed on cultured phytoplankton (Chaetoceros gracilis) attained metamorphic competence within 22–24 days after fertilization. Competent larvae were forced to delay metamorphosis for up to 5 months by preventing them from settling in culture bottles with continuous stirring on a set of 10 rpm rotating rollers and larval survival per monthly intervals was recorded. Larval survival was highest at 24 days, when competence was attained (0 delayed period), and there were no significant differences among the four species. Larvae that had experienced a prolonged delay had reduced survival rate, metamorphosis success, and juvenile survival, but among older larvae, Em had the highest success followed by Ea, Eo, and Ec. Juveniles from larvae of all four species that metamorphosed soon after becoming competent tended to have higher growth rates (test diameter and length of spines) than juveniles from larvae that metamorphosed after a prolonged period of competence with progressively slower growth the longer the prolonged period. Despite the adverse effects of delaying metamorphosis on growth parameters, competent larvae of all four species were able to survive up to 5 months and after metamorphosis grew into 1-month-old juveniles in lab condition. Overall, delayed larvae of Em showed significantly higher larval survival, metamorphosis, and juvenile survival than Ea and Eo, while Ec showed the lowest values in these performances. Em has the most widespread distribution of these species ranging from Africa to Hawaii, while Ec probably has the most restricted distribution. Consequently, differences in distribution may be related to differences in the ability to delay metamorphosis.
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Kawashima. "Metamorphosis as Origin–Koji Yamamura’s Short Animation Franz Kafka’s A Country Doctor". Arts 8, nr 2 (22.04.2019): 54. http://dx.doi.org/10.3390/arts8020054.
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In the beginning was metamorphosis. This paradoxical thought, which the ancient Roman poet Ovidius and modern author Franz Kafka represented in their literary works, is visualized in Koji Yamamura’s short animation Franz Kafka’s A Country Doctor. Diverse metamorphoses that do and do not appear in the Kafka original are so elaborately and dynamically depicted in this animation that no live-action film could possibly represent them. In addition, the film itself can be seen as a metamorphosis, as it is an animation converted from a short story. Such a dominance of metamorphosis is also true for the transculturality and transnationalism of Yamamura’s animation. In a sense, the film results from a cultural integration of foreign language and image. However, this integration is also part of the swirl of metamorphosis. The traditional performance art Kyogen, which the director uses to voice the main characters in the animation, could not integrate foreign culture without its own diversification. Yamamura’s animation demonstrates that transculturality is another name for fundamental metamorphosis in which diversification and integration occur simultaneously.
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Eri, R., J. M. Arnold, V. F. Hinman, K. M. Green, M. K. Jones, B. M. Degnan i M. F. Lavin. "Hemps, a novel EGF-like protein, plays a central role in ascidian metamorphosis". Development 126, nr 24 (15.12.1999): 5809–18. http://dx.doi.org/10.1242/dev.126.24.5809.
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All chordates share several characteristic features including a dorsal hollow neural tube, a notochord, a pharynx and an endostyle. Unlike other chordate taxa, ascidians have a biphasic life-history with two distinct body plans. During metamorphosis, the larval nerve cord and notochord degenerate and the pharyngeal gill slits and endostyle form. While ascidians, like other marine invertebrates, metamorphose in response to specific environmental cues, it remains unclear how these cues trigger metamorphosis. We have identified a novel gene (Hemps) which encodes a protein with a putative secretion signal sequence and four epidermal growth factor (EGF)-like repeats which is a key regulator of metamorphosis in the ascidian Herdmania curvata. Expression of Hemps increases markedly when the swimming tadpole larva becomes competent to undergo metamorphosis and then during the first 24 hours of metamorphosis. The Hemps protein is localised to the larval papillae and anterior epidermis of the larva in the region known to be required for metamorphosis. When the larva contacts an inductive cue the protein is released, spreading posteriorly and into the tunic as metamorphosis progresses. Metamorphosis is blocked by incubating larvae in anti-Hemps antibodies prior to the addition of the cue. Addition of recombinant Hemps protein to competent larvae induces metamorphosis in a concentration-dependent manner. A subgroup of genes are specifically induced during this process. These results demonstrate that the Hemps protein is a key regulator of ascidian metamorphosis and is distinct from previously described inducers of this process in terrestrial arthropods and aquatic vertebrates.
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Kuzmin, Sergius L. "Feeding of amphibians during metamorphosis". Amphibia-Reptilia 18, nr 2 (1997): 121–31. http://dx.doi.org/10.1163/156853897x00017.
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AbstractThe feeding ecology of 28 amphibian species with complete life cycles has been studied from the last pre-metamorphic stages to metamorphosed juveniles. The widespread view that feeding ceases completely during metamorphosis is not confirmed. Generally, however, amphibian feeding rate decreases at metamorphosis. Foraging in Caudata either does not cease (Hynobiidae, rheophilous Salamandridae) or ceases only before the end of transformation, which takes less than one metamorphic stage. The cessation of foraging in Anura coincides with the transformation of the mouth and digestive tract at the beginning of the metamorphic climax. Foraging on small animals starts just after the change from a larval to a post-metamorphic mouth, i.e., before the end of metamorphosis.
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Todd, Christopher D., Matthew G. Bentley i Jonathan N. Havenhand. "Larval metamorphosis of the opisthobranch molluscAdalaria proxima(Gastropoda: Nudibranchia): the effects of choline and elevated potassium ion concentration". Journal of the Marine Biological Association of the United Kingdom 71, nr 1 (luty 1991): 53–72. http://dx.doi.org/10.1017/s0025315400037395.
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Veliger larvae of the nudibranch molluscAdalaria proximaare triggered to metamorphose to the benthic form by the adult prey bryozoan,Electro pilosa.Ion substitution and supplementation experiments with artificial sea water (ASW) have, however, shown that metamorphosis can be induced by elevation of the potassium ion concentration alone. Approximately 19 mM K+ASW (10 mM ‘excess’) was found to elicit maximal metamorphic responses: 29 and 39 mM K+ASW had no inductive effect. Choline chloride was also found to induce metamorphosis in a dose-dependent manner, with lO M ineffective, 10 M approximately threshold, and 5×10 M to 10 M optimal. Concentrations of choline >10 M were sub-lethally toxic. That the absence of larval metamorphosis on exposure to 29 and 39 mM K ASW was due to inhibition is inferred from interaction experiments with choline: at these concentrations of K, metamorphosis in response to choline could be abolished. Timed-exposure experiments indicated that artificial induction elicited by elevated K and choline involve either separate mechanisms, or different parts of the same pathway. Thus, whilst larvae required to be continuously exposed to 19 mM K ASW in order to complete metamorphosis, those exposed to 10 M choline would subsequently complete development in normal ASW following only 1–2 h exposure to the inducer. Preliminary experiments failed to specify further the nature of the natural inducer, beyond the confirmation that live intact colonies of the bryozoanElectro pilosawill trigger larvae to metamorphose.
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Watkins, T. B. "The effect of metamorphosis on the repeatability of maximal locomotor performance in the Pacific tree frog Hyla regilla." Journal of Experimental Biology 200, nr 20 (1.10.1997): 2663–68. http://dx.doi.org/10.1242/jeb.200.20.2663.
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Measuring the repeatability of inter-individual differences in locomotor performance is an important first step in elucidating both the functional causes and the ecological consequences of performance variation. Thus, repeatability of whole-animal performance traits provides a crucial link between functional and evolutionary biology. In the present study, repeatability of maximal burst locomotor performance was estimated for a single population of the Pacific tree frog Hyla regilla. Animals were reared individually from eggs through metamorphosis in the laboratory. Maximum burst swimming speed of tadpoles was measured before metamorphosis (Gosner stage 37) and again at the onset of the metamorphic climax (stage 42). Maximum jump distance was measured on the same individuals as juvenile frogs. Locomotor performance was repeatable over a 24h period for both premetamorphic tadpoles and juvenile frogs. Performance was not repeatable across metamorphosis or between any two of the three developmental stages investigated. A high-performance individual at one developmental stage does not necessarily retain that performance advantage at another stage. This lack of repeatability contrasts sharply with several previous studies on non-metamorphosing vertebrates, but concurs with a single previous study on a metamorphosing salamander. Metamorphosis appears to place strict temporal constraints on individual consistency in locomotor ability.
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Beachy, Christopher, i Richard Bruce. "Life history of a small form of the plethodontid salamander Desmognathus quadramaculatus". Amphibia-Reptilia 24, nr 1 (2003): 13–26. http://dx.doi.org/10.1163/156853803763806902.
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AbstractWe sampled Desmognathus quadramaculatus, one of the largest species of plethodontid salamanders in eastern North America, from a population exhibiting extremely small adult body sizes in the Bald Mountains of North Carolina (USA). In order to test the hypothesis that miniaturization in desmognathine salamanders is due to early metamorphosis and maturation, we estimated ages and sizes at metamorphosis and maturation. Analysis of size-frequency distributions suggests that most larvae metamorphose after 24 months, with the remainder metamorphosing after 36. The minimum age of sexually mature individuals in the summer months is estimated to be 4 years in males and 5 years in females; some may mature 1 year earlier. This is earlier than other reliable estimates of age at maturation in D. quadramaculatus, and appears to account for the small size of the species at this locality. Larval and juvenile growth rates are within the range of growth rates of other populations. As in other populations of D. quadramaculatus, males are smaller than females at maturation, but grow to larger sizes. Estimates of clutch sizes based on dissection of gravid females are relatively low. The other species of salamanders in this community do not appear to be miniaturized.
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McWilliam, Paulette S., i Bruce F. Phillips. "Metamorphosis of the final phyllosoma and secondary lecithotrophy in the puerulus of Panulirus cygnus George: a review". Marine and Freshwater Research 48, nr 8 (1997): 783. http://dx.doi.org/10.1071/mf97159.
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The final phyllosoma of Panulirus cygnus metamorphoses to a non-feeding puerulus that lives on energy reserves accumulated in the final larva, and the metamorphic moult occurs mainly in the slope region adjoining the shelf-break off Western Australia. A review of the literature on field studies, laboratory rearing and nutritional studies of phyllosomal and other decapod zoeal larvae provided no evidence that metamorphosis in P. cygnus (or other shallow-water palinurids) is triggered by a direct environmental cue. It did indicate that metamorphosis results from the culmination of sustained nutrition and reserve energy levels through the later larval phase. Therefore, since the puerulus is secondarily lecithotrophic, it is considered that metamorphosis occurs only after the final phyllosoma has reached some critical, specific, level of stored energy reserves. Appropriate food for later larval development and successful metamorphosis of P. cygnus is more abundant in the shelf-break region (than further offshore) because this is a region of high plankton and micronekton biomass dominated by the Leeuwin Current. It also explains why metamorphosis occurs mainly in the shelf-break region. This review indicates research necessary for evaluation of the present interpretation and of larval recruitment processes in this species.
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Watters, G. Thomas. "Glochidial metamorphosis of the freshwater mussel Lampsilis cardium (Bivalvia: Unionidae) on larval tiger salamanders, Ambystoma tigrinum ssp. (Amphibia: Ambystomidae)". Canadian Journal of Zoology 75, nr 3 (1.03.1997): 505–8. http://dx.doi.org/10.1139/z97-062.
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Larval tiger salamanders (Ambystoma tigrinum ssp.) were infected with glochidia of the freshwater mussel Lampsilis cardium in laboratory experiments. At 20–21 °C, metamorphosis occurred from 9 to 39 days, primarily between 9 and 17 days. The percentage of attached glochidia that metamorphosed varied from 0.27 to 15.7%. Metamorphosis on the salamanders occurred more quickly than on a known piscine host, largemouth bass (Micropterus salmoides), but a smaller percentage of the total attached glochidia metamorphosed. The role of amphibians as hosts of freshwater mussels in North America has not been addressed. Recognizing such a relationship could have important consequences for our understanding of mussel zoogeography.
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Băncilă, Raluca Ioana, Florina Stănescu, Rodica Plăiaşu, Ioana Nae, Diana Székely, Sabina E. Vlad i Dan Cogălniceanu. "Food and light availability induce plastic responses in fire salamander larvae from contrasting environments". PeerJ 11 (4.10.2023): e16046. http://dx.doi.org/10.7717/peerj.16046.
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Phenotypic plasticity has been proposed as a mechanism facilitating the colonisation and adaptation to novel environments, such as caves. However, phenotypic plasticity in subterranean environments remains largely unexplored. Here, we test for plasticity in growth and development of fire salamander larvae (Salamandra salamandra) from subterranean and surface habitats, in response to contrasting food availability and light conditions. We hypothesized that: (i) low food availability and absence of light decrease larval growth and delay metamorphosis, (ii) light conditions mediate the effects of food availability on growth and time to metamorphosis, and (iii) larval response to contrasting light and food conditions is shaped by the habitat of origin. Our study showed that reduced food availability significantly delayed metamorphosis and slowed total length and body mass growth rates, while exposure to constant darkness slowed body mass growth rate. However, larvae slowed growth rates and increased time to metamorphosis without compromising size at metamorphosis. The effect of food availability on growth and time to metamorphosis did not change under different light conditions. Fire salamanders from subterranean and surface habitats responded differently only in relation to contrasting food availability conditions. Specifically, larvae from the surface habitat grew faster in high food conditions, while growth in larvae from the subterranean habitat was not influenced by food availability. Initial size also appeared to be an influential factor, since larger and heavier larvae grew slower, metamorphosed faster, and the size advantage was maintained in newly-metamorphosed juveniles. Overall, the results of our experiment suggest that plasticity and local adaptation favor the exploitation of aquatic subterranean habitats for breeding by fire salamanders, allowing successful development even under food shortage and day-length constraints, without compromising metamorphic size. Our findings have implications for conservation because they confirm that phenotypic plasticity plays a critical role in allowing fire salamanders to overcome altered environmental conditions.
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Webster, Nicole S., Luke D. Smith, Andrew J. Heyward, Joy E. M. Watts, Richard I. Webb, Linda L. Blackall i Andrew P. Negri. "Metamorphosis of a Scleractinian Coral in Response to Microbial Biofilms". Applied and Environmental Microbiology 70, nr 2 (luty 2004): 1213–21. http://dx.doi.org/10.1128/aem.70.2.1213-1221.2004.
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ABSTRACT Microorganisms have been reported to induce settlement and metamorphosis in a wide range of marine invertebrate species. However, the primary cue reported for metamorphosis of coral larvae is calcareous coralline algae (CCA). Herein we report the community structure of developing coral reef biofilms and the potential role they play in triggering the metamorphosis of a scleractinian coral. Two-week-old biofilms induced metamorphosis in less than 10% of larvae, whereas metamorphosis increased significantly on older biofilms, with a maximum of 41% occurring on 8-week-old microbial films. There was a significant influence of depth in 4- and 8-week biofilms, with greater levels of metamorphosis occurring in response to shallow-water communities. Importantly, larvae were found to settle and metamorphose in response to microbial biofilms lacking CCA from both shallow and deep treatments, indicating that microorganisms not associated with CCA may play a significant role in coral metamorphosis. A polyphasic approach consisting of scanning electron microscopy, fluorescence in situ hybridization (FISH), and denaturing gradient gel electrophoresis (DGGE) revealed that coral reef biofilms were comprised of complex bacterial and microalgal communities which were distinct at each depth and time. Principal-component analysis of FISH data showed that the Alphaproteobacteria, Betaproteobacteria, Gammaproteobacteria, and Cytophaga-Flavobacterium of Bacteroidetes had the largest influence on overall community composition. A low abundance of Archaea was detected in almost all biofilms, providing the first report of Archaea associated with coral reef biofilms. No differences in the relative densities of each subdivision of Proteobacteria were observed between slides that induced larval metamorphosis and those that did not. Comparative cluster analysis of bacterial DGGE patterns also revealed that there were clear age and depth distinctions in biofilm community structure; however, no difference was detected in banding profiles between biofilms which induced larval metamorphosis and those where no metamorphosis occurred. This investigation demonstrates that complex microbial communities can induce coral metamorphosis in the absence of CCA.
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Rabby, Ahmad Fazley, Turabur Rahman, Zahidul Islam, Jakia Hasan, Md Aktaruzzaman, Shafiqur Rahman, Ehsanul Karim i Md Zulfikar Ali. "Growth, Development and Survival Rate of The Blue Swimming Crab (Portunus pelagicus) Cultured using Different Larvae Feeds". ILMU KELAUTAN: Indonesian Journal of Marine Sciences 29, nr 1 (24.02.2024): 147–55. http://dx.doi.org/10.14710/ik.ijms.29.1.147-155.
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Blue swimming crab (Portunus pelagicus) is one of the most important commodities of softshell industry. Besides mud crab its demand as feed is increasing day by day. As a coastal dominant country, Bangladesh has a great feasibility of this species in culture, production, use and export. However, the production contribution from Bangladesh is still from natural sources and far behind in terms of farming, culture and production. Optimization of larval rearing techniques is therefore important to develop intensive hatchery rearing technique for this species. So, this study is aimed to develop larvae production technique of Portunus pelagicus with a better survival rate. Newly hatched first zoeal of Portunus pelagicus were reared using three different diets till second zoeal stage: (Treatment 1= Artemia franciscana umbrella + Rotifer (Brachionus rotundiformis); Treatment 2= Rotifer (B. rotundiformis) and Treatment 3= Artemia franciscana umbrella). Then, Artemia franciscana nauplii were used for all three treatments till they metamorphosed to crab instar. Regularly, water quality parameters were monitored and maintained and the survival and molting to next stages was observed. The result showed that, all the hatched zoea of P. pelagicus could successfully turns into crab instar stage under all the treatment applied, but the highest survival rate 6.08% was found in case of treatment 2 followed by 0.58%, 0.91%, respectively in treatment 1 and 3. In terms of metamorphosis, it took more than 15 and 14 days respectively from zoea 1 to metamorphose into megalopa for treatments 1 and 3, whereas metamorphosis from zoea 1 to megalopa in treatment 2 finished at the 12th day with a higher Larval Stage Index (LSI) value which was 4.9. Finally, at the 15th day larvae were metamorphosed into crablet for treatment 2 and 18 and 16 days required for metamorphosis into crablets for treatment 1 and 3, respectively. However, the larval feed showed a significant effect on growth and survival of P. pelagicus larvae, whereas the earlier larval stage of P. pelagicus rearing with Rotifer (B. rotundiformis) is found as the most suitable diet.
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Gavrić, Jelena P., Svetlana G. Despotović, Branka R. Gavrilović, Tijana B. Radovanović, Tamara G. Petrović, Maja Ajduković, Tijana Vučić, Milena Cvijanović, Caterina Faggio i Marko D. Prokić. "Oxidative Stress Parameters in Goitrogen-Exposed Crested Newt Larvae (Triturus spp.): Arrested Metamorphosis". International Journal of Environmental Research and Public Health 18, nr 18 (13.09.2021): 9653. http://dx.doi.org/10.3390/ijerph18189653.
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Thiourea is an established disruptor of thyroid hormone synthesis and is frequently used as an inhibitor of metamorphosis. The changes caused by thiourea can affect processes associated with the oxidative status of individuals (metabolic rate, the HPI axis, antioxidant system). We investigated the parameters of oxidative stress in crested newt (Triturus spp.) larvae during normal development in late larval stage 62 and newly metamorphosed individuals, and during thiourea-stimulated metamorphosis arrest in individuals exposed to low (0.05%) and high (0.1%) concentrations of thiourea. Both groups of crested newts exposed to thiourea retained their larval characteristics until the end of the experiment. The low activities of antioxidant enzymes and the high lipid peroxidation level pointed to increased oxidative stress in larvae at the beginning of stage 62 as compared to fully metamorphosed individuals. The activities of catalase (CAT) and glutathione-S-transferase (GST) and the concentration of sulfhydryl (SH) groups were significantly lower in larvae reared in aqueous solutions containing thiourea than in newly metamorphosed individuals. The high thiourea concentration (0.1%) affected the antioxidative parameters to the extent that oxidative damage could not be avoided, contrary to a lower concentration. Our results provide a first insight into the physiological adaptations of crested newts during normal development and simulated metamorphosis arrest.
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Lochet, Aude, J. Ellen Marsden, Brian J. Fryer i Stuart A. Ludsin. "Instability of statolith elemental signatures revealed in newly metamorphosed sea lamprey (Petromyzon marinus)". Canadian Journal of Fisheries and Aquatic Sciences 70, nr 4 (kwiecień 2013): 565–73. http://dx.doi.org/10.1139/cjfas-2012-0410.
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Techniques that use calcified structures to identify the natal origin of organisms assume that reworking of previously deposited material does not occur. While verified for otoliths, this assumption remains unverified for statoliths. Herein, we test the stability of sea lamprey (Petromyzon marinus) statolith microchemistry during metamorphosis. Using laser ablation inductively coupled plasma mass spectrometry, we quantified the concentrations of nine elements in statoliths from sea lamprey larvae (n = 118) and newly metamorphosed (n = 115) individuals that were collected across six tributaries of varying alkalinity in the Laurentian Great Lakes and Lake Champlain basins. In newly metamorphosed individuals from all streams, the portion of the statolith deposited during the larval stage was enriched in rubidium (Rb), strongly suggesting a chemical reworking of statoliths during metamorphosis. As the ability to discriminate among sea lamprey from different streams in the Great Lakes and Lake Champlain mostly relies on premetamorphic levels of Rb, strategies for the use of statoliths to identify the natal origin of sea lamprey parasitic juveniles and spawners (postmetamorphic stages) should take into account the chemical changes associated with metamorphosis.
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Shikuma, Nicholas J., Igor Antoshechkin, João M. Medeiros, Martin Pilhofer i Dianne K. Newman. "Stepwise metamorphosis of the tubewormHydroides elegansis mediated by a bacterial inducer and MAPK signaling". Proceedings of the National Academy of Sciences 113, nr 36 (22.08.2016): 10097–102. http://dx.doi.org/10.1073/pnas.1603142113.
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Diverse animal taxa metamorphose between larval and juvenile phases in response to bacteria. Although bacteria-induced metamorphosis is widespread among metazoans, little is known about the molecular changes that occur in the animal upon stimulation by bacteria. Larvae of the tubewormHydroides elegansmetamorphose in response to surface-boundPseudoalteromonas luteoviolaceabacteria, producing ordered arrays of phage tail-like metamorphosis-associated contractile structures (MACs). Sequencing theHydroidesgenome and transcripts during five developmental stages revealed that MACs induce the regulation of groups of genes important for tissue remodeling, innate immunity, and mitogen-activated protein kinase (MAPK) signaling. Using two MAC mutations that blockP. luteoviolaceafrom inducing settlement or metamorphosis and three MAPK inhibitors, we established a sequence of bacteria-induced metamorphic events: MACs induce larval settlement; then, particular properties of MACs encoded by a specific locus inP. luteoviolaceainitiate cilia loss and activate metamorphosis-associated transcription; finally, signaling through p38 and c-Jun N-terminal kinase (JNK) MAPK pathways alters gene expression and leads to morphological changes upon initiation of metamorphosis. Our results reveal that the intricate interaction betweenHydroidesandP. luteoviolaceacan be dissected using genomic, genetic, and pharmacological tools.Hydroides' dependency on bacteria for metamorphosis highlights the importance of external stimuli to orchestrate animal development. The conservation ofHydroidesgenome content with distantly related deuterostomes (urchins, sea squirts, and humans) suggests that mechanisms of bacteria-induced metamorphosis inHydroidesmay have conserved features in diverse animals. As a major biofouling agent, insight into the triggers ofHydroidesmetamorphosis might lead to practical strategies for fouling control.
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Pawlik, Joseph R. "Larval settlement and metamorphosis of two gregarious sabellariid polychaetes:Sabellaria alveolatacompared withPhragmatopoma californica". Journal of the Marine Biological Association of the United Kingdom 68, nr 1 (luty 1988): 101–24. http://dx.doi.org/10.1017/s002531540005013x.
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Two sabellariid polychaetes,Sabellaria alveolatafrom European waters andPhragmatopoma californicafrom the west coast of North America, are known from previous work to have larvae that settle and metamorphose preferentially on the cemented sand tubes of conspecific adults. The naturally occurring inducers of larval metamorphosis were recently isolated and identified forP. californica.In the present study, larval behaviour ofS. alveolataandP. californicawas compared in reciprocal laboratory settlement assays. For both species, metamorphosis occurred to a greater extent on conspecific tube sand than on control sand or on heterospecific tube sand. Extraction of the tube sand ofS. alveolatawith organic solvents diminished its capacity to induce metamorphosis pi conspecific larvae, but this capacity was not transferred to the extracts, as was the case forP. californica. The substance responsible for the enhanced metamorphosis ofS. alveolataon conspecific tube sand remains unknown. The free fatty acid (FFA) inducers of larval metamorphosis ofP. californicaeither inhibited, or had no effect on, metamorphosis ofS. alveolata. Both species responded abnormally upon exposure to unnaturally high concentrations of certain (particularly polyenoic) FFAs. Abnormal larval responses ofS. alveolata, however, did not incorporate behavioural components of normal metamorphosis, as were observed forP. californica. FFAs were isolated from the natural tube sand ofS. alveolataat less than one-tenth the concentration found in the natural tube sand ofP. californica. The differences between the two species provide further evidence that a very specific mechanism is responsible for the perception of FFAs by the larvae ofP. californica.
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Southerden, Francesca. "'Ad modum floris': Petrarch's Narcissus between the Rerum vulgarium fragmenta and Triumphi". Modern Language Review 119, nr 1 (styczeń 2024): 89–113. http://dx.doi.org/10.1353/mlr.2024.a916729.
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ABSTRACT: This article analyses Petrarch's treatment of Narcissus in his vernacular poetry, focusing on his inclusion of an aspect of the myth not usually found in medieval vernacular rewritings of Ovid's Metamorphoses : the flower which seals Narcissus's metamorphosis. Setting Petrarch's flower-Narcissus in dialogue with passages from the anonymous fourteenth-century Ovide moralisé demonstrates the poet's distinctive treatment of the myth relative to his lyric and romance precursors even as he preserves its significance for dramatizing the ambivalent pleasures of erōs . Desiring 'in the manner of the flower' affects lover and beloved alike, with implications for how we read vegetal metamorphosis in Petrarch.
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Szurawitzki, Michael. "Becks Konzept der Metamorphose und Flecks Denkstil. Überlegungen zu ihrer Verschränkung". tekst i dyskurs - text und diskurs, nr 12 (2019) (27.12.2019): 235–58. http://dx.doi.org/10.7311/tid.12.2019.13.
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In this paper, an interweaving of the concepts of metamorphosis, developed by Ulrich Beck, and the scientific thinking style of Ludwik Fleck is suggested. Due to our own relevant preliminary work, it seems obvious to bring these two concepts together for the purpose of a theoretical connection useful for linguistics, especially for discourse linguistics. After a short introduction (1) and a review of the state of research on Fleck’s theory of cognition (2), the core term “metamorphosis” is semantically determined (3), and comments are made on the relevance of the concept. This is followed by an analysis of Beck’s The Metamorphosis of the World, which focuses on the concept of metamorphosis as he sees it (4). Here, the linguistic relevance of the concept is emphasized, which Beck mentions explicitly. This is followed by a section on Ludwik Fleck’s Genesis and Development of a Scientific Fact (5.). Here, comments are made on Fleck’s thinking style and on the thinking collective. On this basis, the synthesis of Beck’s and Fleck’s ideas is sought (6.), a directed perception with a view to social metamorphoses. This can best be done linguistically using the discourse-linguistic multi-layer analysis (DIMEAN), as proposed by Spitzmüller/Warnke. DIMEAN is presented accordingly, and subsequently modified for the analysis of linguistic manifestations of metamorphosis (6.1). Using the example of various linguistic metamorphosis phenomena from the discourse around the German federal elections of 2017–2018, the applicability of the combination of Beck’s and Fleck’s ideas is then tested (6.2). The article concludes with a summary and perspectives for further research (7).
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Belles, Xavier. "The innovation of the final moult and the origin of insect metamorphosis". Philosophical Transactions of the Royal Society B: Biological Sciences 374, nr 1783 (26.08.2019): 20180415. http://dx.doi.org/10.1098/rstb.2018.0415.
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The three modes of insect postembryonic development are ametaboly, hemimetaboly and holometaboly, the latter being considered the only significant metamorphosis mode. However, the emergence of hemimetaboly, with the genuine innovation of the final moult, represents the origin of insect metamorphosis and a necessary step in the evolution of holometaboly. Hemimetaboly derives from ametaboly and might have appeared as a consequence of wing emergence in Pterygota, in the early Devonian. In extant insects, the final moult is mainly achieved through the degeneration of the prothoracic gland (PG), after the formation of the winged and reproductively competent adult stage. Metamorphosis, including the formation of the mature wings and the degeneration of the PG, is regulated by the MEKRE93 pathway, through which juvenile hormone precludes the adult morphogenesis by repressing the expression of transcription factor E93, which triggers this change. The MEKRE93 pathway appears conserved in extant metamorphosing insects, which suggest that this pathway was operative in the Pterygota last common ancestor. We propose that the final moult, and the consequent hemimetabolan metamorphosis, is a monophyletic innovation and that the role of E93 as a promoter of wing formation and the degeneration of the PG was mechanistically crucial for their emergence. This article is part of the theme issue ‘The evolution of complete metamorphosis’.
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Smith, Peter R., i Fu-Shiang Chia. "Larval development and metamorphosis of Sabellaria cementarium Moore, 1906 (Polychaeta: Sabellariidae)". Canadian Journal of Zoology 63, nr 5 (1.05.1985): 1037–49. http://dx.doi.org/10.1139/z85-156.
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The development of the polychaete Sabellaria cementarium Moore, 1906 proceeds at 10–14 °C, as follows: 23 h, early trochophore with prototroch and apical tuft; 65 h, 1 pair of provisional setae; 3.5 days, feeding trochophore; 18 days, metatrochophore; 4 weeks, metatrochophore with tentacle buds; 5–6 weeks, nectochaeta competent to metamorphose; 6–8 weeks, settlement and metamorphosis. Larval behavior is described. Tube sand of adult sabellariids (S. cementarium, Phragmatopoma lapidosa, ldanthrysus ornamentatus) and beach sand induced metamorphosis. Larvae exhibit a low degree of substrate specificity in their settlement, but sand is essential. Metamorphosis involves a loss of provisional setae, anterior rotation of tentacles and opercular cirri, and reduction of episphere. Following these changes, the juvenile secretes a mucoid tube to which sand grains are attached. Metamorphosis is considered complete when the caudal appendage has formed; this occurs 7–10 days postsettlement. Juveniles were kept in the laboratory for 38 days. During this time, they develop three pairs of tentacles, lose all larval pigment, and form a second thoracic segment. Within the opercular crown, primary opercular paleae replace settling paleae.
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Chazal, Anne C., John D. Krenz i David E. Scott. "Relationship of larval density and heterozygosity to growth and survival of juvenile marbled salamanders (Ambystoma opacum)". Canadian Journal of Zoology 74, nr 6 (1.06.1996): 1122–29. http://dx.doi.org/10.1139/z96-124.
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Intraspecific competition and enzyme variability have been observed to influence the bioenergetics of many organisms. In amphibians, larval growth affects body size at metamorphosis, which in turn can lead to differences in adult survival and fecundity. We manipulated larval density in a population of the marbled salamander, Ambystoma opacum, and measured body size and enzyme variability in surviving newly metamorphosed juveniles. Crowded larval conditions resulted in lower survival and smaller body sizes at metamorphosis. Multilocus heterozygosity showed no relation to body size at high larval densities; however, at low larval densities relatively homozygous animals were larger. There was a significant interaction between heterozygosity and larval density in their effects on larval traits. Competition had a greater effect on body size at metamorphosis than did heterozygosity. Survival may be enhanced by heterozygosity but in a manner unrelated to body size.
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Oesterdiekhoff, Georg W. "Belief in Metamorphosis". Anthropos 115, nr 2 (2020): 371–88. http://dx.doi.org/10.5771/0257-9774-2020-2-371.
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The idea that the borders between different natural species can be easily bridged by metamorphoses was central to the ancient worldview. Humans were believed to be able to undress their human appearance and to transform into any beast whichever, or, conversely, animals were believed to appear as human beings. This belief permeated daily life and ritual practice. The notion of metamorphosis was also central to ancient metaphysics: it affected ideas regarding creation and maintenance of the cosmos, as well as birth and death of living beings. This article demonstrates that developmental psychology can explain both the universal existence of this belief in premodern societies and its disappearance in modern societies. People staying on the preoperational stage cannot avoid believing in metamorphosis because it is an inevitable part of the cognitive patterns of this stage. People staying on the concrete and formal operational stages are in fact no more able to share these ideas because the notion of the invariance of natural kinds is an inevitable part of higher psychological stages. The article points to the fundamental importance of developmental psychology for ethnological research, especially for the study of ancient worldview.
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Jeffs, Andrew G., Stephen M. Chiswell i John D. Booth. "Distribution and condition of pueruli of the spiny lobster Jasus edwardsii offshore from north-east New Zealand". Marine and Freshwater Research 52, nr 8 (2001): 1211. http://dx.doi.org/10.1071/mf01182.
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Pelagic spiny lobster, Jasus edwardsii, pueruli and phyllosomas were sampled on offshore transects from the south-east coast of the North Island of New Zealand in February 1998. Carapace length, weight, and total lipid content of pueruli (n = 360) were assessed; 33 pueruli had soft carapaces, indicative of recent metamorphosis from final-stage (stage 11) phyllosoma larvae. The recently metamorphosed pueruli occurred 24–216 km offshore, much farther offshore than has been previously suggested for the location of metamorphosis. Their distribution was compared to information on their size and condition, as well as their distance offshore, water depth, temperature and salinity, and estimates of phytoplankton biomass. The results indicate that a threshold of larval energy reserve is unlikely to trigger metamorphosis, but rather some exogenous trigger may be involved, or metamorphosis may be part of a programmed developmental process. The distribution and condition of the new pueruli suggest that about 84% had the energetic capacity to swim inshore to settle. This result may have important implications for patterns of puerulus settlement and subsequent recruitment of lobsters to coastal populations and their important associated fisheries. It may influence both the seasonal and interannual variability in settlement observed in this species.
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Thumm, Karen, i Michael Mahony. "The effect of water level reduction on larval duration in the red-crowned toadlet Pseudophryne australis (Anura: Myobatrachidae): Bet-hedging or predictive plasticity?" Amphibia-Reptilia 27, nr 1 (2006): 11–18. http://dx.doi.org/10.1163/156853806776052137.
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AbstractField observations indicate that when faced with the desiccation of their ephemeral ponds, the tadpoles of Pseudophryne australis, a semi-endotrophic myobatrachid frog, do not accelerate metamorphosis, and total reproductive losses are a frequent event. In this experiment we tested whether tadpoles were able to accelerate developmental rates when subjected to a decline in the water level. Tadpoles were divided into three treatments: water was held either at a constant level, or was removed at a slow or a fast rate. There were no significant differences in the mean length of larval duration in the three groups, and the distribution of ages at metamorphosis was asynchronous in all treatments. Metamorphosis first started at day 39 and continued in similar proportions up to day 57 in all treatments, after which a higher proportion of tadpoles from the desiccation treatments metamorphosed than in the constant deep-water group. This trend was reflected in statistically significant, but minor differences in developmental stage between treatments. These results suggest a combination of diversified bet-hedging and predictive plasticity. There was a significant positive relationship between age and weight at metamorphosis.
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Veres, Ottilia. "Spaces in Between in the Myth of Myrrha: A Metamorphosis into Tree". Acta Universitatis Sapientiae, Philologica 11, nr 1 (1.11.2019): 83–92. http://dx.doi.org/10.2478/ausp-2019-0006.
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Abstract Within the larger context of metamorphoses into plants in Greek and Roman mythology, the paper aims to analyse the myth of Myrrha and her metamorphosis into a tree, focusing on the triggering cause of the transformation as well as the response given to her newly-acquired form of life. Myrrha’s transformation into a myrrh tree takes place as a consequence of her transgressive incestuous act of love with her father, Cinyras. Her metamorphosis occurs as a consequence of sinful passion – passion in extremis –, and she sacrifices her body (and human life/existence) in her escape. I will look at Ovid’s version of the myth as well as Ted Hughes’s adaptation of the story from his Tales from Ovid. My discussion of the transformation into tree starts out from the consideration that metamorphosis is the par excellence place and space of in-betweenness implying an inherent hybridity and blurred, converging subjectivities, a state of being that allows for passages, overlaps, crossings, and simultaneities. I am interested to see in what ways Myrrha’s incestuous desire for her father as well as her metamorphosis into a tree can be “rooted” back to her great-grandfather Pygmalion’s transgressive love for the ivory statue Galatea.
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Hulse, Clark. "Ovid’s urban metamorphosis". Sederi, nr 29 (2019): 85–108. http://dx.doi.org/10.34136/sederi.2019.4.
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In Book XV of Ovid’s Metamorphoses, Pythagoras meditates on the rise and fall of cities and foresees that the survival of Rome requires turning from war to the “arts of peace.” Once ancient Rome has fallen, its urban imagery hybridizes with a Biblical counter-imagery in which God wills the ruination of Rome and other centers of wickedness. Through this Ovidian/Pythagorean lens, this essay then examines how Spenser confronts the fall and rise and possible fall again of early modern London, with glances also at Shakespeare and Dryden. This Ovidian model creates challenges of identity, belief, and ethical obligation that result in an “outward turn” of the theme of metamorphosis toward its social boundary.
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Tabassum, Samirah. "Between and Beyond Metamorphosing Identity:". Crossings: A Journal of English Studies 13, nr 2 (1.12.2022): 100–112. http://dx.doi.org/10.59817/cjes.v13i2.452.
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This paper offers a critical comparative reading of the representation of animal and racial metamorphoses in Franz Kafka’s The Metamorphosis (1915) and A. Igoni Barrett’s Blackass (2015), respectively, with a view to underscoring how the processes and consequences of metamorphosing identity foreground biopolitics. While the first novel muses on the transformation of Gregor Samsa, a human being, into a monstrous vermin, the second novel, a farcical take on Kafka’s narrative, traces the transformation of Furo Wariboko, a black Nigerian, into a white-skinned man. The comparison is premised upon two axes: first, the human-animal interaction and tension that inform anthropocentric speciesism on one hand and the civilized-white/savage-black binary opposition on the other; second, the circuits of economic privilege and social accommodation. Exploring the ways in which we identify ourselves and are identified by the people in power, the paper locates the identity rubric of the human subjects in two different settings where the logic of the world is disturbed by unusual transformations and the disabled/non-disabled binary is put in a dialogue. In its enterprise of unmasking disability from its hegemonic referents, the paper incorporates insights from Disability Studies, Critical Posthumanism, Critical Race Theory, and Critical Animal Studies. By exploring the potential of debility’s capacitation, that is, the extraction and exploitation of “body maiming” and/or “body capacities” in The Metamorphosis and Blackass, this paper suggests a non-anthropocentric interspecies vision of affective politics.
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Kukkonen, Karin. "Metamorphosis: Embodied Narrative at Play in the Seventeenth-Century Fairy Tale". Marvels & Tales 37, nr 2 (2023): 157–74. http://dx.doi.org/10.1353/mat.2023.a923680.
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Abstract: This article discusses how the seventeenth-century French fairy tale investigates embodiment through the figure of metamorphosis in the examples of Charles Perrault's "The Mirror or the Metamorphosis of Orante" (1661), Charlotte-Rose de La Force's "Les jeux d'esprit" (1701) and "Plus Belle que Fée" (1698), and Marie-Catherine d'Aulnoy's "La Chatte Blanche" (1696). These fairy-tale metamorphoses do not present a rich embodied language, but rather invite us to reconsider the dichotomies between mind and body, at stake in Cartesian philosophy, and between cognition and culture, central to today's conceptualization of the mind as "extended" beyond the body. Deploying the marvelous in playful ways, the conteuses take embodiment beyond the limits of everyday mimesis.
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Simith, Darlan J. B., Karen Diele i Fernando A. Abrunhosa. "Influence of natural settlement cues on the metamorphosis of fiddler crab megalopae, Uca vocator (Decapoda: Ocypodidae)". Anais da Academia Brasileira de Ciências 82, nr 2 (czerwiec 2010): 313–21. http://dx.doi.org/10.1590/s0001-37652010000200007.
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Megalopae of many decapod crab species accelerate their development time to metamorphosis (TTM) when exposed to natural physical and/or chemical cues characteristic of the parental habitat. In the present study, the influence of natural settlement cues on the moulting rates and development TTM in megalopae of the fiddler crab Uca vocator was investigated. The effects of mud from different habitats (including well-preserved and degraded-polluted mangrove habitats) and conspecific adult 'odours' (seawater conditioned with crabs) on the induction of metamorphosis were compared with filtered pure seawater (control). 95 to 100% of the megalopae successfully metamorphosed to first juvenile crab stage in all treatments, including the control. However, the development TTM differed significantly among treatments. Settlement cues significantly shortened development, while moulting was delayed in their absence. The fact that megalopae responded to metamorphosis-stimulating cues originating from both adult and non-adult benthic habitats demonstrates that settlement in this species may occur in a wider range of habitats within the mangrove ecosystem, including impacted areas.