Journal articles: 'Animal metamorphosis'

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Holmes, John A., Helen Chu, Syeda A. Khanam, Richard G. Manzon, and John H. Youson. "Spontaneous and induced metamorphosis in the American brook lamprey, Lampetra appendix." Canadian Journal of Zoology 77, no. 6 (October 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, and Richard Wassersug. "Lung use and development in Xenopus laevis tadpoles." Canadian Journal of Zoology 72, no. 4 (April 1, 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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Byrne, Isabel, Robyn Thomson, Rory Thomson, Duncan Murray-Uren, and J. Roger Downie. "Observations on metamorphosing tadpoles of Hyalinobatrachium orientale (Anura: Centrolenidae)." Phyllomedusa: Journal of Herpetology 19, no. 2 (December 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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Cavalcanti, Giselle S., Amanda T. Alker, Nathalie Delherbe, Kyle E. Malter, and Nicholas J. Shikuma. "The Influence of Bacteria on Animal Metamorphosis." Annual Review of Microbiology 74, no. 1 (September 8, 2020): 137–58. http://dx.doi.org/10.1146/annurev-micro-011320-012753.

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The swimming larvae of many marine animals identify a location on the seafloor to settle and undergo metamorphosis based on the presence of specific surface-bound bacteria. While bacteria-stimulated metamorphosis underpins processes such as the fouling of ship hulls, animal development in aquaculture, and the recruitment of new animals to coral reef ecosystems, little is known about the mechanisms governing this microbe-animal interaction. Here we review what is known and what we hope to learn about how bacteria and the factors they produce stimulate animal metamorphosis. With a few emerging model systems, including the tubeworm Hydroides elegans, corals, and the hydrozoan Hydractinia, we have begun to identify bacterial cues that stimulate animal metamorphosis and test hypotheses addressing their mechanisms of action. By understanding the mechanisms by which bacteria promote animal metamorphosis, we begin to illustrate how, and explore why, the developmental decision of metamorphosis relies on cues from environmental bacteria.

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Shikuma, Nicholas J., Igor Antoshechkin, João M. Medeiros, Martin Pilhofer, and 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, no. 36 (August 22, 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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Chelgren, Nathan D., Daniel K. Rosenberg, Selina S. Heppell, and Alix I. Gitelman. "Individual variation affects departure rate from the natal pond in an ephemeral pond-breeding anuran." Canadian Journal of Zoology 86, no. 4 (April 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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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, no. 20 (October 1, 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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Kuzmin, Sergius L. "Feeding of amphibians during metamorphosis." Amphibia-Reptilia 18, no. 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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DARE, O. K., and M. R. FORBES. "Rates of development in male and female Wood Frogs and patterns of parasitism by lung nematodes." Parasitology 135, no. 3 (November 9, 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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Youson, J. H., J. A. Holmes, J. A. Guchardi, J. G. Seelye, R. E. Beaver, J. E. Gersmehl, S. A. Sower, and 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, no. 11 (November 1, 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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Mushegian, Alexandra A. "How bacteria induce animal metamorphosis." Science Signaling 9, no. 445 (September 13, 2016): ec211-ec211. http://dx.doi.org/10.1126/scisignal.aaj1824.

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Beachy, Christopher, and Richard Bruce. "Life history of a small form of the plethodontid salamander Desmognathus quadramaculatus." Amphibia-Reptilia 24, no. 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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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, no. 1 (January 1, 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, and 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, no. 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., and John H. Youson. "Fall condition factor and temperature influence the incidence of metamorphosis in sea lampreys, Petromyzon marinus." Canadian Journal of Zoology 72, no. 6 (June 1, 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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Bone, Jane. "Metamorphosis: Play, Spirituality and the Animal." Contemporary Issues in Early Childhood 11, no. 4 (January 2010): 402–14. http://dx.doi.org/10.2304/ciec.2010.11.4.402.

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Holmes, J. A., F. W. H. Beamish, J. G. Seelye, S. A. Sower, and 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, no. 9 (September 1, 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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Kaji, Takao, Yoichi Hoshino, Yasuhisa Henmi, and Kinya Yasui. "Longitudinal Observation of Japanese Lancelet, Branchiostoma japonicum, Metamorphosis." Dataset Papers in Biology 2013 (September 23, 2013): 1–6. http://dx.doi.org/10.7167/2013/839671.

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The lancelet (amphioxus) performs metamorphosis and produces minute and ciliate pelagic larvae commonly found in other metamorphic marine invertebrates. During larval life and metamorphosis, however, the animal displays interesting combination of features not found in other animals such as long coexistence of ciliate and muscular locomotion and no change in feeding behavior. The uniqueness of lancelet metamorphosis can provide important data to understand the evolutionary history of this animal as well as the metamorphosis broadly appeared in metazoans. Although lancelet metamorphosis has been studied, all previous studies depended on cross-sectional observations. To get serial data on metamorphic events, we performed longitudinal observations on the Japanese lancelet under the culture condition and confirmed the following: (1) there were individual variations of the duration of metamorphosis from 15 to 27 days; (2) growth was arrested for a month and the maximum reduction of the body length (2.2%–3.2%) occurred when gill slits became paired; (3) during rather long duration of metamorphosis, the oral transformation and the division of the gill pores by tongue bar were completed within two to four days. Our observations suggest that the duration and mode of lancelet metamorphosis depend mainly on intrinsic requirements rather than on extrinsic selective pressures.

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Thumm, Karen, and 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, no. 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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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, no. 3 (March 1, 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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Kencana, Bayu Bagus, Muhammad Fathur Prayudha, and Budi Arifitama. "METAMORPHOSIS VISUALIZATION WITH AUGMENTED REALITY USING MARKER-BASED TRACKING." Jurnal Riset Informatika 3, no. 1 (November 30, 2020): 1–6. http://dx.doi.org/10.34288/jri.v3i1.168.

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Metamorphosis is a cycle of biological animal growth. Learning Metamorphosis is a part of learning for students in schools specifically in the area of biology subjects. Unfortunately, the observing activities take time, and finding an animal specimen is limited to study the metamorphosis cycle. This research proposes an innovative solution to overcome these problems which is the implementation of augmented reality technology. The animal metamorphosis cycle process is visualized into 4-dimensional objects to improve interaction for the student on learning metamorphosis during learning sessions. The Marker-Based Tracking method is used as an approach where the location of the tracking pattern on the marker has been determined in advance as the place where the augmented reality object appears. The results of this study indicate that using a marker-based tracking method can improve students' understanding of metamorphosis.

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Chazal, Anne C., John D. Krenz, and David E. Scott. "Relationship of larval density and heterozygosity to growth and survival of juvenile marbled salamanders (Ambystoma opacum)." Canadian Journal of Zoology 74, no. 6 (June 1, 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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Wilson, Alexander D. M., and Jens Krause. "Metamorphosis and animal personality: a neglected opportunity." Trends in Ecology & Evolution 27, no. 10 (October 2012): 529–31. http://dx.doi.org/10.1016/j.tree.2012.07.003.

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Smith, Peter R., and Fu-Shiang Chia. "Larval development and metamorphosis of Sabellaria cementarium Moore, 1906 (Polychaeta: Sabellariidae)." Canadian Journal of Zoology 63, no. 5 (May 1, 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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Hammer, Tobin J., and Nancy A. Moran. "Links between metamorphosis and symbiosis in holometabolous insects." Philosophical Transactions of the Royal Society B: Biological Sciences 374, no. 1783 (August 26, 2019): 20190068. http://dx.doi.org/10.1098/rstb.2019.0068.

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Many animals depend on microbial symbionts to provide nutrition, defence or other services. Holometabolous insects, as well as other animals that undergo metamorphosis, face unique constraints on symbiont maintenance. Microbes present in larvae encounter a radical transformation of their habitat and may also need to withstand chemical and immunological challenges. Metamorphosis also provides an opportunity, in that symbiotic associations can be decoupled over development. For example, some holometabolous insects maintain the same symbiont as larvae and adults, but house it in different tissues; in other species, larvae and adults may harbour entirely different types or numbers of microbes, in accordance with shifts in host diet or habitat. Such flexibility may provide an advantage over hemimetabolous insects, in which selection on adult-stage microbial associations may be constrained by its negative effects on immature stages, and vice versa. Additionally, metamorphosis itself can be directly influenced by symbionts. Across disparate insect taxa, microbes protect hosts from pathogen infection, supply nutrients essential for rebuilding the adult body and provide cues regulating pupation. However, microbial associations remain completely unstudied for many families and even orders of Holometabola, and future research will undoubtedly reveal more links between metamorphosis and microbiota, two widespread features of animal life. This article is part of the theme issue ‘The evolution of complete metamorphosis’.

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Yamakawa, Shumpei, Yoshiaki Morino, Hisanori Kohtsuka, and Hiroshi Wada. "Retinoic Acid Signaling Regulates the Metamorphosis of Feather Stars (Crinoidea, Echinodermata): Insight into the Evolution of the Animal Life Cycle." Biomolecules 10, no. 1 (December 25, 2019): 37. http://dx.doi.org/10.3390/biom10010037.

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Many marine invertebrates have a life cycle with planktonic larvae, although the evolution of this type of life cycle remains enigmatic. We recently proposed that the regulatory mechanism of life cycle transition is conserved between jellyfish (Cnidaria) and starfish (Echinoderm); retinoic acid (RA) signaling regulates strobilation and metamorphosis, respectively. However, the function of RA signaling in other animal groups is poorly understood in this context. Here, to determine the ancestral function of RA signaling in echinoderms, we investigated the role of RA signaling during the metamorphosis of the feather star, Antedon serrata (Crinoidea, Echinodermata). Although feather stars have different larval forms from starfish, we found that exogenous RA treatment on doliolaria larvae induced metamorphosis, like in starfish. Furthermore, blocking RA synthesis or binding to the RA receptor suppressed metamorphosis. These results suggested that RA signaling functions as a regulator of metamorphosis in the ancestor of echinoderms. Our data provides insight into the evolution of the animal life cycle from the viewpoint of RA signaling.

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Shaughnessy, Robert. "Twentieth-Century Fox: Volpone's Metamorphosis." Theatre Research International 27, no. 1 (February 14, 2002): 37–48. http://dx.doi.org/10.1017/s0307883302001049.

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Since it was restored to the English theatre during the 1930s, Volpone has enjoyed a unique currency amongst Ben Jonson's works; it has had a more consistent and successful performance history than any other of his plays. Although its beast fable scheme has apparently rendered it more immediately accessible (and allegedly more universal) than the author's humours comedies, it has also provoked responses of ambivalence and unease, in that its coupling of the animal and the human actively unsettles the ethical relations between nature, culture, economics and morality that the allegory ostensibly intends to clarify. In performance, the play has given rise to a critical discourse of vituperation, deviance and excess which reflects the tensions and contradictions endemic to the cultural vocabulary of anthropomorphism. Theatre practice has dealt with the play's problems and provocations by incorporating the image of the animal into an inclusive, consensual and predominantly realist mode of characterization and mise en scène. A notable exception was in 1968, when Tyrone Guthrie directed a production for the National Theatre at the Old Vic which literalized animal identities to the point of excess. The result was a radically contradictory rethinking of the play, and of the performance vocabularies which have been, and can be, deployed to animate it.

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Borić, Dušan. "Body Metamorphosis and Animality: Volatile Bodies and Boulder Artworks from Lepenski Vir." Cambridge Archaeological Journal 15, no. 1 (April 2005): 35–69. http://dx.doi.org/10.1017/s095977430500003x.

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This article discusses the notion of body metamorphosis as a theory of phenomenal change by examining carved representational and ‘aniconic’ boulders from Lepenski Vir and other Meso-Neolithic sites in the Danube Gorges. The voluminous size of the boulders at Lepenski Vir, the way in which they occupy the three-dimensional space within buildings and around hearths, and the carvings over their surfaces suggest that they were understood as volatile bodies, undergoing continuous metamorphoses. The relationship between the seasonal recurrence of the Danube's migratory fish and these boulders is explored through the notion of animality. These boulders indicate prescribed stages of life-cycle metamorphosis that affected inextricably-linked realms of human and animal worlds. Prescribed stages of social embodiment at Lepenski Vir are discerned by looking at the archaeological context of representational boulders that sometimes directly commemorate particular deceased individuals. The possibility that boulder artworks acted as sacred heirlooms of particular buildings is connected to the social efficacy they might have acquired.

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Anderson, J. E., A. Cunha, and M. F. Docker. "Novel “omega muscle units” in superficial body-wall myotomes during metamorphosis in the northern brook lamprey (Ichthyomyzon fossor)." Canadian Journal of Zoology 97, no. 12 (December 2019): 1218–24. http://dx.doi.org/10.1139/cjz-2019-0051.

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Lampreys transform from sedentary filter feeders to more mobile adults through a dramatic metamorphosis that includes remodeling of head muscle and skeletal systems. Metamorphic modifications of body-wall myotomes that could support changes in swimming behavior from larvae to adults have not been previously reported. Thus, transverse sections of northern brook lamprey (Ichthyomyzon fossor Reighard and Cummins, 1916) in larval (n = 4), metamorphosing (n = 3), and adult (n = 2) stages were used to investigate the architecture of body-wall muscle and to detect whether Pax7 and MyoD, proteins important in myogenesis, were co-localized in any muscle nuclei. In addition to myotomal complexity of muscle units composed of parietal and central fibers, there was a novel pattern of omega-shaped muscle units with curves of muscle fibers in the superficial mid-body myotome in metamorphosing lamprey. Small satellite-like cells were identified on central fibers in metamorphosing and adult lamprey muscle using routine histology and immunolocalization of Pax7 and MyoD with antibodies that specifically detect mammalian and teleost proteins. Transient “omega muscle units” may be a marker for impending myotomal growth and increasing swimming efficiency during maturation, possibly restricted to metamorphosis. Finding satellite-like cells suggests that Pax7 and MyoD may have distinctive roles in lamprey myogenesis.

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Liang, Xiao, Xiu-Kun Zhang, Li-Hua Peng, You-Ting Zhu, Asami Yoshida, Kiyoshi Osatomi, and Jin-Long Yang. "The Flagellar Gene Regulates Biofilm Formation and Mussel Larval Settlement and Metamorphosis." International Journal of Molecular Sciences 21, no. 3 (January 21, 2020): 710. http://dx.doi.org/10.3390/ijms21030710.

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Biofilms are critical components of most marine systems and provide biochemical cues that can significantly impact overall community composition. Although progress has been made in the bacteria–animal interaction, the molecular basis of modulation of settlement and metamorphosis in most marine animals by bacteria is poorly understood. Here, Pseudoalteromonas marina showing inducing activity on mussel settlement and metamorphosis was chosen as a model to clarify the mechanism that regulates the bacteria–mussel interaction. We constructed a flagellin synthetic protein gene fliP deletion mutant of P. marina and checked whether deficiency of fliP gene will impact inducing activity, motility, and extracellular polymeric substances of biofilms. Furthermore, we examined the effect of flagellar proteins extracted from bacteria on larval settlement and metamorphosis. The deletion of the fliP gene caused the loss of the flagella structure and motility of the ΔfliP strain. Deficiency of the fliP gene promoted the biofilm formation and changed biofilm matrix by reducing β-polysaccharides and increasing extracellular proteins and finally reduced biofilm-inducing activities. Flagellar protein extract promoted mussel metamorphosis, and ΔfliP biofilms combined with additional flagellar proteins induced similar settlement and metamorphosis rate compared to that of the wild-type strain. These findings provide novel insight on the molecular interactions between bacteria and mussels.

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AMANO, SHIGETOYO, and ISAO HORI. "Metamorphosis of calcareous sponges II. Cell rearrangement and differentiation in metamorphosis." Invertebrate Reproduction & Development 24, no. 1 (September 1993): 13–26. http://dx.doi.org/10.1080/07924259.1993.9672327.

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Hayes, Tyrone B. "Role of Corticosterone in Anuran Metamorphosis and Potential Role in Stress-Induced Metamorphosis." Netherlands Journal of Zoology 45, no. 1-2 (1994): 107–9. http://dx.doi.org/10.1163/156854295x00681.

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Lambert, Charles C., Ilsa M. Lambert, and Gretchen Lambert. "Brooding strategies in solitary ascidians: Corella species from north and south temperate waters." Canadian Journal of Zoology 73, no. 9 (September 1, 1995): 1666–71. http://dx.doi.org/10.1139/z95-198.

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Corella inflata from the northwest Pacific coast of North America and Corella eumyota from southern New Zealand are both ovoviviparous solitary ascidians with very different methods of brood retention. Corella inflata eggs are covered with large follicle cells that are responsible for flotation. The floating eggs are trapped in the upwardly situated atrial chamber, where development ensues. Corella eumyota eggs have small follicle cells and do not float; the follicle cells produce a viscous glue that causes the eggs and embryos to stick to each other and to the right atrium. The follicle cells are not sticky when removed from the ovary but become so in about 15 min. In C. inflata, development to hatching requires 24–26 h at 13 °C and metamorphosis begins 17 h later. Corella eumyota tadpoles hatch at about 25 h at 15 °C and begin metamorphosis 11 h later. Both species retain the tadpoles well beyond hatching and release tadpoles fully competent to metamorphose. In C. inflata the tadpoles swim down and out of the atrium; C. eumyota tadpoles somehow break free of the glue-encrusted vitelline coat and swim out the atrial siphon. Tadpoles of both species swim vigorously when released and then rapidly metamorphose. Most tadpoles metamorphose in 15–20 min. Since both species spawn around dawn, tadpoles are released during the night.

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Bender, Melissa Cui, Caroline Hu, Chris Pelletier, and Robert J. Denver. "To eat or not to eat: ontogeny of hypothalamic feeding controls and a role for leptin in modulating life-history transition in amphibian tadpoles." Proceedings of the Royal Society B: Biological Sciences 285, no. 1875 (March 28, 2018): 20172784. http://dx.doi.org/10.1098/rspb.2017.2784.

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Many animal life histories entail changing feeding ecology, but the molecular bases for these transitions are poorly understood. The amphibian tadpole is typically a growth and dispersal life-history stage. Tadpoles are primarily herbivorous, and they capitalize on growth opportunities to reach a minimum body size to initiate metamorphosis. During metamorphic climax, feeding declines, at which time the gastrointestinal (GI) tract remodels to accommodate the carnivorous diet of the adult frog. Here we show that anorexigenic hypothalamic feeding controls are absent in the tadpole, but develop during metamorphosis concurrent with the production of the satiety signal leptin. Before metamorphosis there is a large increase in leptin mRNA in fat tissue. Leptin receptor mRNA increased during metamorphosis in the preoptic area/hypothalamus, the key brain region involved with the control of food intake and metabolism. This corresponded with an increase in functional leptin receptor, as evidenced by induction of socs3 mRNA and phosphorylated STAT3 immunoreactivity, and suppression of feeding behaviour after injection of recombinant frog leptin. Furthermore, we found that immunoneutralization of leptin in tadpoles at metamorphic climax caused them to resume feeding. The absence of negative regulation of food intake in the tadpole allows the animal to maximize growth prior to metamorphosis. Maturation of leptin-responsive neural circuits suppresses feeding during metamorphosis to facilitate remodelling of the GI tract.

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Székely, Paul, Dan Cogălniceanu, and Marian Tudor. "Effect of habitat drying on the development of the Eastern spadefoot toad (Pelobates syriacus) tadpoles." Amphibia-Reptilia 31, no. 3 (2010): 425–34. http://dx.doi.org/10.1163/156853810791769536.

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AbstractAmphibians exhibit plasticity in the timing of metamorphosis, and tadpoles of many species respond to pond drying by accelerating their development. In the present study we investigated the phenotypic plasticity of the developmental response to water volume reduction in tadpoles of Eastern spadefoot toad Pelobates syriacus. The response of tadpoles to the simulated drying conditions was evaluated by gradually reducing the water level in the experimental containers under controlled laboratory conditions. Four water level treatments were used: constant high, slow decrease, fast decrease and constant low level. We tested if (i) tadpoles can speed up their development in a drying aquatic habitat, and (ii) if the accelerated development causes a reduced body size at metamorphosis. Our results showed that P. syriacus tadpoles were able to respond to pond drying by speeding up their metamorphosis and that metamorphosis was not influenced by water level, but by water level decrease rate. The accelerated development caused by the decreasing water level resulted in smaller body size at metamorphosis. The smallest size at metamorphosis was in tadpoles raised in constant low water level treatments and was probably induced by the crowding effect. We compared our results to similar studies which show that the response of the Eastern spadefoot toad tadpoles to pond drying is less impressive, especially if compared to the response of the North American spadefoot toads inhabiting desert environments.

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Reiss, John O. "The phylogeny of amphibian metamorphosis." Zoology 105, no. 2 (January 2002): 85–96. http://dx.doi.org/10.1078/0944-2006-00059.

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Beck, Christopher W., and Justin D. Congdon. "Effects of individual variation in age and size at metamorphosis on growth and survivorship of southern toad (Bufo terrestris) metamorphs." Canadian Journal of Zoology 77, no. 6 (October 10, 1999): 944–51. http://dx.doi.org/10.1139/z99-041.

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We conducted two experiments with the southern toad (Bufo terrestris) to examine whether individual variation in (i) metamorph body size and metabolic rate and (ii) age and size at metamorphosis were related to differences in survivorship or growth rate of postmetamorphic individuals. Results from the first experiment indicated that neither initial body size nor metabolic rate was related to survivorship or growth. Results from the second experiment showed that (i) size at metamorphosis was positively correlated with survivorship to first census (after 2 weeks), (ii) age and size at metamorphosis had no significant effect on survivorship from first to second census (after 2 months), (iii) size at metamorphosis had a marginally significant positive effect on survivorship from metamorphosis to second census, and (iv) age and size at metamorphosis were not significantly correlated with total growth. Our results suggest that in the southern toad, size at metamorphosis may lead to early differences in survival, size, and growth that later disappear. Furthermore, early differences in growth and survival attributable to size at metamorphosis are not due to size-related differences in metabolic rate. Therefore, although age and size at metamorphosis affect metabolic rate, they may not be related to fitness via effects on postmetamorphic survival and growth.

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Rutkowski, Paweł. "Animal Transformation in Early Modern English Witchcraft Pamphlets." Anglica. An International Journal of English Studies, no. 28/1 (September 20, 2019): 21–34. http://dx.doi.org/10.7311/0860-5734.28.1.02.

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Animal metamorphosis was a traditional component of witchcraft beliefs during the European early modern witch-hunts, during which it was taken for granted that witches could and did turn into animals regularly in order to easier do evil. It must be noted, however, that the witch-turned-animal motif was much less common in England, where witches did possess the shape-shifting abilities but relatively rarely used them. A likely reason for the difference, explored in the present paper, was the specifically English belief that most witches were accompanied and served by familiar spirits, petty demons that customarily assumed the shape of animals. It seems that the ubiquity of such demonic shape-shifters effectively satisfied the demand for magical transformations in the English witchcraft lore.

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Hyojoung Kim. "A Study of the Animal Metamorphosis Motif in Turkic Folklores." Journal of Mediterranean Area Studies 12, no. 4 (November 2010): 79–105. http://dx.doi.org/10.18218/jmas.2010.12.4.79.

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Hansen, Paul. "Becoming bovine: Mechanics and metamorphosis in Hokkaido's animal-human-machine." Journal of Rural Studies 33 (January 2014): 119–30. http://dx.doi.org/10.1016/j.jrurstud.2013.02.001.

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Levi, G., F. Broders, D. Dunon, G. M. Edelman, and J. P. Thiery. "Thyroxine-dependent modulations of the expression of the neural cell adhesion molecule N-CAM during Xenopus laevis metamorphosis." Development 108, no. 4 (April 1, 1990): 681–92. http://dx.doi.org/10.1242/dev.108.4.681.

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During amphibian metamorphosis, a complete remodeling of the phenotype takes place under complex hormonal control whose final effectors are thyroid hormones. This process implies the activation of coordinated programs of cell death, proliferation, migration, adhesion and differentiation. Inasmuch as the neural cell adhesion molecule N-CAM is thought to play a central role in the control of morphogenetic processes, we have studied by immunohistofluorescence and immunoblots the patterns of expression of N-CAM at different stages of Xenopus laevis metamorphosis. A scan was made of all major organs and appendages. Before the metamorphic climax, all neuronal cell bodies and processes express high levels of N-CAM. During the metamorphic climax, N-CAM expression decreases sharply on the cell bodies and processes of the peripheral nervous system (PNS) but remains high in the central nervous system (CNS). Towards the end of metamorphosis, the PNS and spinal nerves are virtually negative for N-CAM while the CNS is still positive. The optic and olfactory nerves, although myelinated, are still strongly positive for N-CAM. The lens and olfactory epithelia express N-CAM throughout metamorphosis. In the brain. N-CAM is present at all times as three polypeptides of 180, 140, and 120 X 10(3) Mr; before metamorphosis some of the N-CAM is in its polysialylated form. During metamorphosis and the subsequent growth of the animal, the amount of N-CAM decreases gradually. In all polypeptides, the polysialylated form is the first to disappear. Cardiac muscle expresses high level of N-CAM from its first formation throughout metamorphosis; in contrast, the level of N-CAM in skeletal muscle is high in newly formed muscles, but decreases rapidly after myoblast fusion. The liver of adult Xenopus contains large amounts of a 160 X 10(3) polypeptide that is recognized by polyclonal and monoclonal antibodies against N-CAM. cDNA probes of Xenopus brain N-CAM recognize major transcripts of 9.2, 3.8 and 3.3 kb in Xenopus liver mRNA; these bands are different in size from those recognized in brain mRNA (9.5, 4.2 and 2.2 kb). Premetamorphic liver does not express the 160 X 10(3) form of N-CAM, which can be first detected at stage 59 and persists then through all the life of the animal. Expression of N-CAM in the liver can be induced in premetamorphic animals (stage 51–52) by a 48 h treatment with thyroxine. All hepatocytes are responsive.(ABSTRACT TRUNCATED AT 400 WORDS)

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Okamura, Akihiro, Yoshiaki Yamada, Naomi Mikawa, Noriyuki Horie, and Katsumi Tsukamoto. "Effect of starvation, body size, and temperature on the onset of metamorphosis in Japanese eel (Anguilla japonica)." Canadian Journal of Zoology 90, no. 12 (December 2012): 1378–85. http://dx.doi.org/10.1139/cjz-2012-0146.

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We assessed the effects of starvation, body size, and water temperature on the onset of metamorphosis in leptocephali of Japanese eel ( Anguilla japonica Temminck and Schlegel, 1846) as determined by the morphological criteria of proportion, preanal length, and body depth to total length. Leptocephali of mean total length 55.6 mm that had been reared in captivity for 241 days from hatching were divided into unfed (n = 28) and fed (n = 30) groups in triplicate and reared for an additional 2 weeks. The mean percentage of larvae starting metamorphosis within 2 weeks was significantly higher in the unfed than in the fed groups (70% vs. 28.6%), suggesting that food deprivation acted as a cue for metamorphosis. The critical size for metamorphosis was a total length of 50–55 mm; smaller larvae did not start metamorphosis even in the absence of food, whereas larvae reaching that critical size were induced to undergo metamorphosis by starvation. The start of metamorphosis under unfed conditions was independent of diel-varying water temperature (day 23 °C; night 21–29 °C), suggesting a high plasticity in response to a wide range of environmental temperatures. These findings suggest methods for the efficient production of glass eels, as well as new insights into the mechanism of eel metamorphosis.

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Lada-Richards, Ismene. ""Closing Up" on Animal Metamorphosis: Ovid's Micro-Choreographies in the Metamorphoses and the Corporeal Idioms of Pantomime Dancing." Classical World 111, no. 3 (2018): 371–404. http://dx.doi.org/10.1353/clw.2018.0023.

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Loman, Jon. "Early metamorphosis in common frog Rana temporaria tadpoles at risk of drying: an experimental demonstration." Amphibia-Reptilia 20, no. 4 (1999): 421–30. http://dx.doi.org/10.1163/156853899x00466.

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AbstractDoes the development rate of common frog tadpoles accelerate if their habitat dries? To study this, the water level in experimental tanks was reduced shortly before time of metamorphosis. Water level remained high in control tanks. The experiment was performed at two different tadpole densities and replicated four times, with tadpoles from different source ponds. The experimental treatment, simulating a drying pond, resulted in earlier metamorphosis while no significant difference in size at metamorphosis was found. Resources per capita decreased as a result of the decreased water level so the increase in development rate was not an effect of feeding conditions. Temperatures in the tanks were such that it is unlikely that the increased development rate was due to temperature effects. I interpret the advancement of metamorphosis as an adaptive response to the threat of drying. This response has been documented for several other anuran species. All those breed in temporary water bodies, supporting the hypothesis that the trait is an evolved adaptation for breeding in such waters.

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de Paulis, Daniela. "The Metamorphosis of a Periplaneta Americana." Leonardo 54, no. 1 (February 2021): 12–22. http://dx.doi.org/10.1162/leon_a_01983.

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The author presents her ongoing artistic research and practice at the intersection of neuroscience and radio astronomy that connects two of her current projects: COGITO in Space and The Metamorphosis. The author focuses primarily on theoretical concepts underpinning her projects, encompassing philosophy of mind and animal ethics. The artistic vision and collaborative work in COGITO in Space has been extensively addressed and presented by the author in previous papers that provide complementary reading to this text.

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Ngo, Binh Van, Ya-Fu Lee, and Chung D. Ngo. "Tadpole Survival and Metamorphosis in the Granular Spiny Frog, Quasipaa verrucospinosa (Dicroglossidae, Anura, Amphibia) in Central Vietnam." Russian Journal of Herpetology 27, no. 2 (April 25, 2020): 63–69. http://dx.doi.org/10.30906/1026-2296-2020-27-2-63-69.

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Little is known about many aspects of the tadpole ecology of Quasipaa verrucospinosa (Bourret, 1937), whereas this species has also been classified as Near Threatened (NT) due to habitat change and degradation, loss of forest and stream habitats and overexploitation. We conducted experiments in the field and collected tadpole data to estimate survival rates, growth rates, and age at metamorphosis. The average number of tadpoles per clutch was 518, the average survival ratio at the final stage of metamorphosis was 80%, and the total time to metamorphosis averaged 55.8 days. Multiple regression results for possible effects of water temperature, dissolved oxygen, and pH values on survival rates and the total time of tadpole metamorphosis were significant among localities. Water temperature and dissolved oxygen, but not pH values, were negatively associated with the survival ratio and metamorphosis time of tadpoles. At the beginning stage of metamorphosis (41 – 42), tadpoles had an average body weight of 2.7 g, a snout-vent length (SVL) of 24.8 mm, a tail length of 40.5 mm, and a total length of 65.3 mm. The process of metamorphosis is completed in stage 46, at which juvenile frogs had a mean body weight of 2.3 g and a mean SVL of 25.8 mm. We used a two-way multivariate analysis of variance to examine the effects of year and site factors on the variance in morphological measurements and body weightes of tadpoles. This analysis revealed that body sizes of tadpoles varied significantly among years, sites, and by site-year interaction. Water temperature and dissolved oxygen have major impacts on rates of growth, timing of metamorphosis, and body size of tadpoles at metamorphosis.

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Kuroki, Mari, Michael J. Miller, and Katsumi Tsukamoto. "Diversity of early life-history traits in freshwater eels and the evolution of their oceanic migrations." Canadian Journal of Zoology 92, no. 9 (September 2014): 749–70. http://dx.doi.org/10.1139/cjz-2013-0303.

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Early life-history traits of all 19 anguillid eel species and subspecies were examined to help understand the evolutionary processes of their oceanic migrations in comparison with their migration distances and the geography of their species ranges. Tropical species were found to have fewer myomeres, greater body depths, higher growth rates, shorter larval durations, and smaller maximum larval sizes than temperate species. The relationships among larval characteristics such as growth rate, age at metamorphosis, and maximum larval size differed among tropical and temperate species and corresponded with the maximum latitudes of their species ranges. Temperate eel leptocephali with slow growth and large maximum size with slender bodies appear to be specialized for long migrations and dispersal over a wide range of distances to higher latitudes, while having flexible sizes of metamorphosis and recruitment. Tropical species with faster growth metamorphose earlier at a relatively fixed size, which would facilitate larval retention near their species ranges at low latitudes. Changes in the early life-history traits of tropical eels appear to have occurred during the evolution of longer migrations as they entered temperate regions.

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Müller, Werner A., and Thomas Leitz. "Metamorphosis in the Cnidaria." Canadian Journal of Zoology 80, no. 10 (October 1, 2002): 1755–71. http://dx.doi.org/10.1139/z02-130.

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The free-living stages of sedentary organisms are an adaptation that enables immobile species to exploit scattered or transient ecological niches. In the Cnidaria the task of prospecting for and identifying a congenial habitat is consigned to tiny planula larvae or larva-like buds, stages that actually transform into the sessile polyp. However, the sensory equipment of these larvae does not qualify them to locate an appropriate habitat from a distance. They therefore depend on a hierarchy of key stimuli indicative of an environment that is congenial to them; this is exemplified by genera of the Anthozoa (Nematostella, Acropora), Scyphozoa (Cassiopea), and Hydrozoa (Coryne, Proboscidactyla, Hydractinia). In many instances the final stimulus that triggers settlement and metamorphosis derives from substrate-borne bacteria or other biogenic cues which can be explored by mechanochemical sensory cells. Upon stimulation, the sensory cells release, or cause the release of, internal signals such as neuropeptides that can spread throughout the body, triggering decomposition of the larval tissue and acquisition of an adult cellular inventory. Progenitor cells may be preprogrammed to adopt their new tasks quickly. Gregarious settlement favours the exchange of alleles, but also can be a cause of civil war. A rare and spatially restricted substrate must be defended. Cnidarians are able to discriminate between isogeneic and allogeneic members of a community, and may use particular nematocysts to eliminate allogeneic competitors. Paradigms for most of the issues addressed are provided by the hydroid genus Hydractinia.

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Shaffer, H. Bradley, Richard K. Grosberg, and Ryuichi Matsuda. "Animal Evolution in Changing Environments with Special Reference to Abnormal Metamorphosis." Copeia 1989, no. 4 (December 27, 1989): 1121. http://dx.doi.org/10.2307/1446024.

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Polhemus, John T. "Animal Evolution in Changing Environments with Special Reference to Abnormal Metamorphosis." Annals of the Entomological Society of America 83, no. 3 (May 1, 1990): 654. http://dx.doi.org/10.1093/aesa/83.3.654.

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Journal articles on the topic 'Animal metamorphosis'

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