References of "Denoël, Mathieu"
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See detailReproductive fitness consequences of progenesis: sex-specific payoffs in safe and risky environments
Denoël, Mathieu ULiege; Drapeau, Laura; Winandy, Laurane ULiege

in Journal of Evolutionary Biology (in press)

Progenesis is considered to have an important role in evolution because it allows the retention of both a larval body size and shape in an adult morphology. However, the cost caused by the adoption of a ... [more ▼]

Progenesis is considered to have an important role in evolution because it allows the retention of both a larval body size and shape in an adult morphology. However, the cost caused by the adoption of a progenetic process in both males and females remains to be explored to explain the success of progenesis and particularly its biased prevalence across the sexes and environments. Here, through an experimental approach, we used a facultative progenetic species, the palmate newt (Lissotriton helveticus) that can either mature at a small size and retain gills or mature after metamorphosis, to test three hypotheses for sex-specific payoffs of progenesis in safe versus risky habitats. Goldfish were used because they caused a higher decline in progenetic than metamorphic newts. We determined that progenetic newts have a lower reproductive fitness than metamorphic newts. We also found that, when compared to metamorphs, progenetic males have lower reproductive activity than progenetic females and that predatory risk affects more progenetic than metamorphic newts. By identifying ultimate causes of the female-biased sex ratios found in nature, these results support the male escape hypothesis, i.e. the higher metamorphosis rate of progenetic males. They also highlight that although progenesis is advantageous in advancing the age at first reproduction, it also brings an immediate fitness cost and this, particularly, in hostile predatory environments. This means that whereas some environmental constraints could favour facultative progenesis, some others, such as predation, can ultimately counter-select progenesis. Altogether, these results improve our understanding of how developmental processes can affect the sexes differently and how species invasions can impair the success of alternative developmental phenotypes. [less ▲]

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See detailTraditionally managed landscapes do not prevent amphibian decline and the extinction of paedomorphosis
Denoël, Mathieu ULiege; Ficetola, G. Francesco; Sillero, Neftali et al

in Ecological Monographs (2019), 89(2),

Eco-cultural landscapes are assumed to be favourable environments for the persistence of biodiversity, but global change may affect differently their terrestrial and aquatic components. Yet, few long-term ... [more ▼]

Eco-cultural landscapes are assumed to be favourable environments for the persistence of biodiversity, but global change may affect differently their terrestrial and aquatic components. Yet, few long-term studies have examined how multiple, global change stressors may affect wetland biodiversity in such environments. Facultative paedomorphosis is a spectacular example of intra-specific variation, in which biphasic (metamorphosing) amphibians coexist with fully aquatic conspecifics which do not metamorphose (paedomorphs). Paedomorphosis is seriously threatened by global change stressors, but it is unknown to what extent traditional management will allow its long-term persistence. Here, we tested the effects of alien species introductions while taking into account land-use and climate changes on the distribution of two polymorphic newt species (Ichthyosaura alpestris and Lissotriton graecus) in Montenegro by using a 68-year data set and Bayesian mixed models integrating complex spatial and temporal structures. We found that, despite the persistence of natural landscapes, metamorphs dramatically declined, and paedomorphs were nearly extirpated, losing 99.9% of their aquatic area of occupancy and all the major populations. Fish introduction was the main determinant of decline for both phenotypes. Climate and the presence of crayfish further contributed to the decline of metamorphs, which started later and was less dramatic than that of paedomorphs. The near extinction of paedomorphosis on a country-wide scale shows how invasive species determine broad scale impacts, which can be even stronger than other global change stressors, and underlines the need for immediate management actions to avoid the extinction of a unique developmental process, paedomorphosis. [less ▲]

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See detailGenetic structure of lake and stream populations in a Pyrenean amphibian (Calotriton asper) reveals evolutionary significant units associated with paedomorphosis
Oromi Farrús, Neus ULiege; Valbuena-Ureña, Emilio; Soler-Membrives, Anna et al

in Journal of Zoological Systematics and Evolutionary Research (2019), 57(2), 418-430

Differences in environmental conditions such as those between lakes and streams can produce phenotypic variation and ultimately promote evolutionary diversification. Some species of newts and salamanders ... [more ▼]

Differences in environmental conditions such as those between lakes and streams can produce phenotypic variation and ultimately promote evolutionary diversification. Some species of newts and salamanders can occupy these habitats and express alternative phenotypes: metamorphs that lose gills at metamorphosis and paedomorphs that retain them at the adult stage. Whereas this process is facultative in some species, it is obligatory in others, thus suggesting that isolation and environmental pressures may have canalized developmental pathways. In this study, we focused our research on the Pyrenean brook newt, Calotriton asper which is present in both lakes and streams, but whose fully aquatic paedomorphic individuals are only present in lakes. We aimed to determine the genetic structure and differentiation of two paedomorphic populations, including their surrounding stream and lake metamorphic populations, to test whether populations of paedomorphs can constitute evolutionary significant units. Although gene flow was identified between lakes and nearby stream populations, there was a low percentage of dispersers, and the paedomorphic populations were genetically differentiated from the populations of metamorphs. It is likely that the studied lakes have offered peculiar conditions that have allowed the development of a paedomorphic phenotype. These populations and phenotypes therefore constitute good models to understand local adaptations. As each of these populations of paedomorphs can be considered evolutionary significant units that cannot be replaced by other nearby populations in case of a population crash, conservation actions should be focused directly on them. [less ▲]

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See detailThe role of predation risk in metamorphosis versus behavioural avoidance: a sex-specific study in a facultative paedomorphic amphibian
Denoël, Mathieu ULiege; Drapeau, Laura; Oromi Farrús, Neus ULiege et al

in Oecologia (2019), 189(3), 637-645

Evolutionary theory predicts the evolution of metamorphosis over paedomorphosis (the retention of larval traits at the adult stage) in response to life in unfavourable habitats and to the benefits of ... [more ▼]

Evolutionary theory predicts the evolution of metamorphosis over paedomorphosis (the retention of larval traits at the adult stage) in response to life in unfavourable habitats and to the benefits of dispersal. Although many organisms are canalised into obligatory complex or simple life cycles, some species of newts and salamanders can express both processes (facultative paedomorphosis). Previous research highlighted the detrimental effect of fish on both metamorphic and paedomorphic phenotypes, but it remains unknown whether predation risk could induce shifts from paedomorphosis to metamorphosis, whether behavioural avoidance could be an alternative strategy to metamorphosis and whether these responses could be sex-biased. Testing these hypotheses is important because metamorphosed paedomorphs are dispersal individuals which could favour the long-term persistence of the process by breeding subsequently in more favourable waters. Therefore, we quantified the spatial behaviour and timing of the metamorphosis of facultative paedomorphic palmate newts Lissotriton helveticus in response to predation risk. We found that fish induced both male and female paedomorphs to hide more often, but behavioural avoidance was not predictive of metamorphosis. Paedomorphs did not metamorphose more in the presence of fish, yet there was an interaction between sex and predation risk in metamorphosis timing. These results improve our understanding of the lower prevalence of paedomorphs in fish environments and of the female-biased sex-ratios in natural populations of paedomorphic newts. Integrating sex-dependent payoffs of polyphenisms and dispersal across habitats is therefore essential to understand the evolution of these processes in response to environmental change. [less ▲]

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See detailIndividual identification and marking techniques for zebrafish
Delcourt, Johann ULiege; Ovidio, Michaël ULiege; Denoël, Mathieu ULiege et al

in Reviews in Fish Biology and Fisheries (2018), 28(4), 839-864

In laboratory fish research, the zebrafish Danio rerio (Cyprinidae) represents the equivalent of the mouse in mammalian research. This species has become a major model for studies in developmental and ... [more ▼]

In laboratory fish research, the zebrafish Danio rerio (Cyprinidae) represents the equivalent of the mouse in mammalian research. This species has become a major model for studies in developmental and behavioural genetics, neurophysiology, biomedicine, ecotoxicology, and behavioural and evolutionary ecology. To meet the need for accurate and reproducible data in both fundamental and applied sciences, it is of primary importance to be able to tag and/or recognize individual zebrafish. However, classic methods used in fish ecology and aquaculture are generally difficult to apply to such small fish. Recently, various new tagging methods have been developed. This paper presents a first review of current identification and marking methods applied to zebrafish, from external observation methods (such as skin pattern recognition, fin clipping, scale regeneration, colour and transgenic methods) to the most advanced technological developments in electronic (low- and high- radio-frequencies PIT tags, microchip) and image analysis methods (video tracking). This review aims to help researchers and zebrafish facility managers select the identification method (ID) best adapted to their needs. The main characteristics of each ID method are examined (including detection range, durability, speed and repetitiveness, ID code combination, size dependence and ethical considerations), and their pros and cons are summarized in a decision table to help select the most appropriate option for a research or management program. Finally, contextual applications of these ID methods and future developments are discussed. [less ▲]

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See detailNA2RE is reliable but aims for improvement: an answer to Vamberger and Fritz (2018)
Sillero, Neftali; Campos, João; Bonardi, Anna et al

in Biologia (2018), 73(11), 1131-1135

A recent paper has suggested that NA2RE, the New Atlas of Amphibians and Reptiles of Europe, does not provide a reliable basis for ecological niche modelling studies due to errors flagging introductions ... [more ▼]

A recent paper has suggested that NA2RE, the New Atlas of Amphibians and Reptiles of Europe, does not provide a reliable basis for ecological niche modelling studies due to errors flagging introductions and missing data for the native range of the pond turtle genus Emys. We point out that the original NA2RE paper already acknowledged that it was not aimed for fine-scale ecological distribution modelling and that it had the objective of stimulating research for improving the maps. New works now complement the Atlas in improving the coverage and providing new distribution maps for species within species complex. Moreover, we stress that the NA2RE web platform at present hosts only the distribution data compiled in 2014 from different sources, using the taxonomy adopted by the authors at the time. As with any large database, it is advisable that these data are carefully evaluated and quality-filtered before their use in scientific studies. We defend the reliability of the NA2RE web platform as the currently most comprehensive resource for the comparative chorological study of amphibians and reptiles in Europe, and encourage publication of updates and additions following the most recent taxonomic changes, to continuously improve this database and the Atlas. [less ▲]

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See detailTowards the end of facultative paedomorphosis in Balkan newts? A focus on Montenegrin populations
Denoël, Mathieu ULiege; Ficetola, G. Francesco; Sillero, Neftali et al

Conference (2018, September 22)

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See detailDispersal and alternative breeding site fidelity strategies in an amphibian
Denoël, Mathieu ULiege; Dalleur, séverine; Langrand, Estelle et al

in Ecography (2018), 41(9), 1543-1555

Dispersal (i.e., movement from a natal or breeding site to another breeding site) is a central process in ecology and evolution as it affects the eco-evolutionary dynamics of spatially structured ... [more ▼]

Dispersal (i.e., movement from a natal or breeding site to another breeding site) is a central process in ecology and evolution as it affects the eco-evolutionary dynamics of spatially structured populations. Dispersal evolution is regulated by the balance between costs and benefits, which is influenced by the individual phenotype (i.e., phenotype-dependent dispersal) and environmental factors (i.e., condition-dependent dispersal). Even though these processes have been extensively studied in species with simple life cycles, our knowledge about these mechanisms in organisms displaying complex life cycles remains fragmentary. In fact, little is specifically known about how the interplay between individual and environmental factors may lead to alternative dispersal strategies that, in turn, lead to the coexistence of contrasted site fidelity phenotypes. In this paper, we examined breeding dispersal in a pond-breeding amphibian, the great crested newt (Triturus cristatus), within usual walking distances for a newt. We took advantage of recent developments in multi-event capture-recapture models and used capture-recapture data (946 newts marked) collected in a spatially structured population occupying a large pond network (73 ponds). We showed a high rate of breeding site infidelity (i.e., pond use) and the coexistence of two dispersal phenotypes, namely, a highly pond faithful phenotype and a dispersing phenotype. Individuals that were site faithful at time t-1 were therefore more likely to remain site faithful at time t. Our results also demonstrated that the probability that individuals belong to one or the other dispersal phenotypes depended on environmental and individual factors. In particular, we highlighted the existence of a dispersal syndrome implying a covariation pattern among dispersal behavior, body size, and survival. Our work opens new research prospects in the evolution of dispersal in organisms displaying complex life cycles and raises interesting questions about the evolutionary pathways that contribute to the diversification of movement strategies in the wild. [less ▲]

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See detailJailed in the mountains: Genetic diversity and structure of an endemic newt species across the Pyrenees
Valbuena-Ureña, Emilio; Oromi Farrús, Neus ULiege; Soler-Membrives, Anna et al

in PLoS ONE (2018), 13(8), 0200214

The Pyrenees represent a natural laboratory for biogeographic, evolutionary and ecological research of mountain fauna as a result of the high variety of habitats and the profound effect of the glacial and ... [more ▼]

The Pyrenees represent a natural laboratory for biogeographic, evolutionary and ecological research of mountain fauna as a result of the high variety of habitats and the profound effect of the glacial and interglacial periods. There is a paucity of studies providing a detailed insight into genetic processes and better knowledge on the patterns of genetic diversity and how they are maintained under high altitude conditions. This is of particular interest when considering the course of past climate conditions and glaciations in a species which is considered site tenacious, with long generation times. Here we analyzed the genetic patterns of diversity and structure of the endemic Pyrenean brook newt (Calotriton asper) along its distribution range, with special emphasis on the distinct habitat types (caves, streams, and lakes), and the altitudinal and geographical ranges, using a total set of 900 individuals from 44 different localities across the Pyrenean mountain range genotyped for 19 microsatellite loci. We found evidence for a negative longitudinal and positive altitudinal gradient of genetic diversity in C. asper populations. The fact that genetic diversity was markedly higher westwards is in accordance with other Pyrenean species. However, the impact of altitudinal gradient on the genetic diversity seems to differ from other species, and mostly from other amphibians. We found that lower altitudes can act as a barrier probably because the lowlands do not provide a suitable habitat for C. asper. Regarding the distinct habitat types, caves had significantly lower values of genetic diversity compared to streams or lakes. The mean FST value was relatively high (0.304) with maximum values as high as 0.771, suggesting a highly structured total population. Indeed, populations were grouped into five subclusters, the eastern populations (cluster 1) remained grouped into two subclusters and the central-western Pyrenees (cluster 2) into three subclusters. The increase of isolation with geographical distance is consistent with the population structure detected. In conclusion, C. asper seems to be adapted to high altitude mountain habitats, and its genetic diversity is higher in the western Pyrenees. In terms of conservation priority, we consider more relevant the populations that represent a reservoir of genetic diversity. [less ▲]

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See detailDryness affects burrowing depth in a semi-fossorial amphibian
Székely, Diana ULiege; Cogălniceanu, Dan; Székely, Paul et al

in Journal of Arid Environments (2018), 155

The fossorial life-history emerged as a response to hostile environmental conditions, such as extreme temperatures and dryness. It evolved independently in different lineages of amphibians, which are ... [more ▼]

The fossorial life-history emerged as a response to hostile environmental conditions, such as extreme temperatures and dryness. It evolved independently in different lineages of amphibians, which are particularly vulnerable to dehydration and require a continuous level of humidity because of their permeable skin. For the first time, we test the hypothesis that amphibians are able to adapt their fossorial behaviour to substrate humidity, using the Pacific horned frogs (Ceratophrys stolzmanni) from the Ecuadorian dry forest as a model. When exposed to dry substrate, the animals burrowed much deeper than the ones in wet soil. The capacity to excavate was particularly high in this species: frogs from the dry treatment could be found at more than one-meter depth after just a few hours. Our results reveal a conditional strategy that contributes to explain the persistence of amphibians in dry environments. [less ▲]

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See detailThe distributions of the six species constituting the smooth newt species complex (Lissotriton vulgaris sensu lato and L. montandoni) – an addition to the New Atlas of Amphibians and Reptiles of Europe
Wielstra, Ben; Canestreli, Daniele; Cvijanović, Milena et al

in Amphibia-Reptilia (2018), 39(2), 252-259

The ‘smooth newt’, the taxon traditionally referred to as Lissotriton vulgaris, consists of multiple morphologically distinct taxa. Given the uncertainty concerning the validity and rank of these taxa, L ... [more ▼]

The ‘smooth newt’, the taxon traditionally referred to as Lissotriton vulgaris, consists of multiple morphologically distinct taxa. Given the uncertainty concerning the validity and rank of these taxa, L. vulgaris sensu lato has often been treated as a single, polytypic species. A recent study, driven by genetic data, proposed to recognize five species, L. graecus, L. kosswigi, L. lantzi, L. schmidtleri and a more restricted L. vulgaris. The Carpathian newt L. montandoni was confirmed to be a closely related sister species. We propose to refer to this collective of six Lissotriton species as the smooth newt or Lissotriton vulgaris species complex. Guided by comprehensive genomic data from throughout the range of the smooth newt species complex we 1) delineate the distribution ranges, 2) provide a distribution database, and 3) produce distribution maps according to the format of the New Atlas of Amphibians and Reptiles of Europe, for the six constituent species. This allows us to 4) highlight regions where more research is needed to determine the positon of contact zones. [less ▲]

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See detailRandom size-assortative mating despite size-dependent fecundity in a Neotropical amphibian with explosive reproduction
Székely, Diana ULiege; Székely, Paul; Denoël, Mathieu ULiege et al

in Ethology (2018), 124(4), 218-226

Sexual selection theory predicts that, when body size is correlated with fecundity, there should be fitness advantages for mate choice of the largest females. Moreover, because larger males are expected ... [more ▼]

Sexual selection theory predicts that, when body size is correlated with fecundity, there should be fitness advantages for mate choice of the largest females. Moreover, because larger males are expected to monopolize the largest females, this should result in an assortative mating based on body size. Although such patterns could be expected in both explosive and prolonged breeders, non-assortative mating should be more widespread in species under time constraints. However, patterns of sexual selection are largely unexplored in explosive breeding species, and contrasting patterns have been found previously. We expect that the active choice of partners may be particularly risky when the time period during which sexual partners are available is severely limited. Therefore, to avoid missing an entire reproductive act, males and females should pair irrespective of traits, such as body size. We tested this hypothesis by investigating the mating patterns of the Pacific horned toad, Ceratophrys stolzmanni, a short-lived fossorial species inhabiting Neotropical dry forests. This species is particularly adequate to test our prediction because it reproduces explosively over the course of a single night per year. Although the number of eggs laid was proportional to the size of females, and individuals of both sexes showed variation in body size, there was no assortative mating based either on size, body condition or age of mates. Egg size was not influenced by either female size or clutch size. The larger body size of females compared to males is likely due to fecundity selection, i.e. the selective pressure that enhances reproductive output. Although we cannot dismiss the possibility that individuals could select their partners based on other criteria than those related to size or age, the results fit well our prediction, showing that the explosive breeding makes improbable an active choice of partners in both sexes and therefore favours a random mating pattern. [less ▲]

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See detailFacultative paedomorphosis as a mechanism promoting intraspecific niche differentiation
Lejeune, Benjamin ULiege; Sturaro, Nicolas ULiege; Lepoint, Gilles ULiege et al

in Oikos (2018), 127(3), 427-439

Organisms with complex life cycles are characterized by a metamorphosis that allows for a major habitat shift and the exploitation of alternative resources. However, metamorphosis can be bypassed in some ... [more ▼]

Organisms with complex life cycles are characterized by a metamorphosis that allows for a major habitat shift and the exploitation of alternative resources. However, metamorphosis can be bypassed in some species through a process called paedomorphosis, resulting in the retention of larval traits at the adult stage and is considered important at both micro- and macroevolutionary scales. In facultatively paedomorphic populations of newts, some individuals retain gills and a fully aquatic life at the adult stage (paedomorphs), while others undergo complete metamorphosis (metamorphs), allowing for a terrestrial life-stage. Because facultative paedomorphosis affects trophic structures and feeding mechanism of newts, one hypothesis is that it may be maintained as a trophic polymorphism, with the advantage to lessen intraspecific competition during the shared aquatic life-stage. Here, we tested this hypothesis combining stomach content data with stable isotope techniques, using carbon and nitrogen stable isotopes, in facultatively paedomorphic alpine newts Ichthyosaura alpestris. Both stomach content and stable isotope analyses showed that paedomorphs had smaller trophic niches and were more reliant on pelagic resources, while metamorphs relied more on littoral resources, corresponding to a polyphenism along the littoral-pelagic axis and the extension of the population's trophic niche to otherwise ‘underused’ pelagic resources by paedomorphs. Interestingly, stable isotopes revealed that the trophic polyphenism was less marked in males than in females and potentially linked to sexual activity. Although paedomorphosis and metamorphosis are primarily seen as results of tradeoffs between the advantages of using aquatic versus terrestrial habitats, this study provides evidence that additional forces, such as intraspecific trophic niche differences between morphs and trophic niche expansion, may play an important role in the persistence of this dimorphism in heterogeneous environments. Moreover, the different patterns found in males and females show the importance of considering sex to understand the evolutionary ecology of trophic polymorphisms. [less ▲]

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See detailEcology and conservation of facultative paedomorphosis in newts
Denoël, Mathieu ULiege

Scientific conference (2018, February 23)

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See detailDes chars et des mares : écologie d’une population de Tritons crêtés au sein d’un réseau de points d’eau d’un site natura2mil
Denoël, Mathieu ULiege; Dalleur, Séverine; Hanoy, Mylène et al

Conference (2018, February 11)

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See detailMorphological integration and alternative life history strategies: a case study in a facultatively paedomorphic newt
Tomašević, Natasa; Cvijanović, Milena; Denoël, Mathieu ULiege et al

in Journal of Experimental Zoology. Part B, Molecular and Developmental Evolution (2017), 328(8), 737-748

Tetrapod limbs are serially homologous structures that represent a particularly interesting model for studies on morphological integration, i.e. the tendency of developmental systems to produce correlated ... [more ▼]

Tetrapod limbs are serially homologous structures that represent a particularly interesting model for studies on morphological integration, i.e. the tendency of developmental systems to produce correlated variation. In newts, limbs develop at an early larval stage and grow continuously, including after the habitat transition from water to land following metamorphosis. However, aquatic and terrestrial environments impose different constraints and locomotor modes that could affect patterns of morphological integration and evolvability. We hypothesize that this would be the case for alternative heterochronic morphs in newts, i.e. aquatic paedomorphs that keep gills at the adult stage and adult metamorphs that are able to disperse on land. To this end, we analysed patterns and strengths of correlations between homologous skeletal elements of the fore- and hindlimbs as well as among skeletal elements within limbs in both phenotypes in the alpine newt, Ichthyosaura alpestris. Our results showed that metamorphs and paedomorphs had similar, general patterns of limb integration. Partial correlations between homologous limb elements and within limb elements were higher in paedomorphs when compared to metamorphs. Decrease in partial correlation between homologous limb elements in metamorphs is accompanied with a higher evolvability of the terrestrial morph. All these results indicate that environmental demands shaped the patterns of morphological integration of alpine newt limbs and that the observed diversity in correlation structure could be related to a qualitative difference in the modes of locomotion between the morphs. [less ▲]

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See detailPond drying cues and their effects on growth and metamorphosis in a fast developing amphibian
Székely, Diana ULiege; Denoël, Mathieu ULiege; Székely, Paul et al

in Journal of Zoology (2017), 303(2), 129-135

The hydroperiod of breeding habitats imposes a strong selection on amphibians and pond-breeding species usually exhibit a high degree of plasticity in the duration of larval period. However, the potential ... [more ▼]

The hydroperiod of breeding habitats imposes a strong selection on amphibians and pond-breeding species usually exhibit a high degree of plasticity in the duration of larval period. However, the potential for phenotypic plasticity in fast developing species was investigated only in a small number of anurans, and the specific response to environmental cues such as low water versus decreasing water level, as well as the effects of such cues on particular developmental stages, are even less understood. In this context, we investigated the plastic response to pond desiccation in a neotropical species (Ceratophrys stolzmanni) by raising tadpoles in three water level treatments: constant high, constant low and decreasing. The growth rates were the highest reported for amphibian tadpoles (up to 0.3g/day) and the time to metamorphosis was short in all treatments, with the fastest developing tadpole metamorphosing in only 16 days after egg deposition. Individuals from the constant high water level treatment had a higher growth rate than those in the other two treatments, whereas decreasing and constant low water levels had similar effects on development, speeding up metamorphosis. In turn, this involved a cost as these tadpoles had a lower body size and mass at metamorphosis than the ones raised in constant high water levels. The final stages of metamorphosis, when tadpoles are the most vulnerable, were shorter in tadpoles exposed to a decreasing water level, allowing them to leave water quickly. Our experiment demonstrates that phenotypic plasticity is maintained even in environments devoid of permanent aquatic habitats. Ceratophryd tadpoles are able to shorten their developmental time when they perceive a risk of desiccation and react similarly to cues coming from the two unfavorable water conditions showing their adaptation to ephemeral and unpredictable breeding habitats. [less ▲]

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