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1.
Zool Res ; 42(2): 234-240, 2021 Mar 18.
Artigo em Inglês | MEDLINE | ID: mdl-33709635

RESUMO

We report on a new amphibian species of the genus Micryletta from Hainan Island, China, based on morphological and molecular analyses. The new species, Micryletta immaculata sp. nov., is diagnosed by a combination of the following morphological characters: medium-sized within genus (SVL 23.3-24.8 mm in males, n=3; 27.7-30.1 mm in females, n=2); dorsum bronze brown to reddish brown in life; dark brown spots and stripes on dorsum and flank absent; flanks largely pigmented with silver white; throat in adult males dark brown; undersides without dark patterns; outer metatarsal tubercle absent; supratympanic fold distinct; webbing between toes basal and poorly developed; tibiotarsal articulation adpressed limb reaching level of tympanum. The new species is divergent from all other congeners based on 16S rRNA gene sequences (3.0%-7.7%). Data on the natural history and male advertisement calls of the new species are provided. Following the IUCN Red List Categories and Criteria, we propose the new species to be listed as Vulnerable B1ab (iii).


Assuntos
Anuros/anatomia & histologia , Anuros/classificação , Distribuição Animal , Animais , Anuros/fisiologia , China , Feminino , Ilhas , Masculino , Especificidade da Espécie
2.
Parasitol Res ; 120(3): 993-1001, 2021 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-33409644

RESUMO

Understanding the processes responsible for structuring communities has been a challenge in ecology, and parasite communities are an excellent system to address this issue. The use of different diversity metrics can help us to understand the determinants of the structure of parasite communities, and in this sense, functional diversity indexes make it possible to measure the variability of organism traits in communities. In this study, we investigate how host body size and habitat use influence the functional diversity of nematode parasite infracommunities. We collected and examined 213 individuals of 11 species of anurans in an area of the Brazilian Atlantic Forest, calculated Rao's quadratic entropy as a measure of functional diversity of parasite infracommunities, and tested if this index was related to host body size and habitat use with an analysis of covariance (ANCOVA). Anuran species varied in body size (from 1.80 to 10.35 cm) and habit use (arboreal, terrestrial, and semiaquatic), and in the functional diversity of parasite infracommunities (Rao's quadratic entropy ranged from 0 to 0.196). We observed that anurans with larger body size and terrestrial habit showed significantly greater functional diversity of parasites. We conclude that anuran characteristics drive the functional diversity of nematode parasite communities, and highlight the importance of using different diversity metrics to understand the determinants in the host-parasite interaction.


Assuntos
Anuros/fisiologia , Anuros/parasitologia , Biodiversidade , Nematoides/isolamento & purificação , Animais , Tamanho Corporal , Brasil , Ecossistema , Interações Hospedeiro-Parasita , Nematoides/classificação , Nematoides/genética , Nematoides/fisiologia
3.
PLoS One ; 15(12): e0243937, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33332425

RESUMO

Translocated captive-bred predators are less skilled at hunting than wild-born predators and more prone to starvation post-release. Foraging in an unfamiliar environment presents many further risks to translocated animals. Knowledge of the diet and foraging behaviour of translocated animals is therefore an important consideration of reintroductions. We investigated the diet of the endangered meso-predator, the eastern quoll Dasyurus viverrinus. We also opportunistically observed foraging behaviour, enabling us to examine risks associated with foraging. Sixty captive-bred eastern quolls were reintroduced to an unfenced reserve on mainland Australia (where introduced predators are managed) over a two year period (2018, 2019). Quolls were supplementary fed macropod meat but were also able to forage freely. Dietary analysis of scats (n = 56) revealed that quolls ate macropods, small mammals, birds, invertebrates, fish, reptiles and frogs, with some between-year differences in the frequency of different diet categories. We also observed quolls hunting live prey. Quolls utilised supplementary feeding stations, indicating that this may be an important strategy during the establishment phase. Our study demonstrated that, in a novel environment, captive-bred quolls were able to locate food and hunt live prey. However, foraging was not without risks; with the ingestion of toxic substances and foraging in dangerous environments found to be potentially harmful. Knowledge of the diet of reintroduced fauna in natural landscapes is important for understanding foraging behaviour and evaluating habitat suitability for future translocations and management.


Assuntos
Comportamento Animal/fisiologia , Comportamento Alimentar/fisiologia , Marsupiais/fisiologia , Animais , Anuros/fisiologia , Austrália , Ecossistema , Carne , Comportamento Predatório/fisiologia
4.
PLoS One ; 15(9): e0239485, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32960914

RESUMO

Environmental temperatures are a major constraint on ectotherm abundance, influencing their distribution and natural history. Comparing thermal tolerances with environmental temperatures is a simple way to estimate thermal constraints on species distributions. We investigate the potential effects of behavioral thermal tolerance (i. e. Voluntary Thermal Maximum, VTMax) on anuran local (habitat) and regional distribution patterns and associated behavioral responses. We tested for differences in Voluntary Thermal Maximum (VTMax) of two sympatric frog species of the genus Physalaemus in the Cerrado. We mapped the difference between VTMax and maximum daily temperature (VTMax-ETMax) and compared the abundance in open and non-open habitats for both species. Physalaemus nattereri had a significantly higher VTMax than P. cuvieri. For P. nattereri, the model including only period of day was chosen as the best to explain variation in the VTMax while for P. cuvieri, the null model was the best model. At the regional scale, VTMax-ETMax values were significantly different between species, with P. nattereri mostly found in localities with maximum temperatures below its VTMax and P. cuvieri showing the reverse pattern. Regarding habitat use, P. cuvieri was in general more abundant in open than in non-open habitats, whereas P. nattereri was similarly abundant in these habitats. This difference seems to reflect their distribution patterns: P. cuvieri is more abundant in open and warmer habitats and occurs mostly in warmer areas in relation to its VTMax, whereas P. nattereri tends to be abundant in both open and non-open (and cooler) areas and occurs mostly in cooler areas regarding its VTMax. Our study indicates that differences in behavioral thermal tolerance may be important in shaping local and regional distribution patterns. Furthermore, small-scale habitat use might reveal a link between behavioral thermal tolerance and natural history strategies.


Assuntos
Anuros/fisiologia , Comportamento Animal/fisiologia , Simpatria/fisiologia , Termotolerância/fisiologia , Animais , Ecossistema , Temperatura
5.
PLoS One ; 15(9): e0239874, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32970785

RESUMO

Beta diversity can be portioned into local contributions to beta diversity (LCBD), which represents the degree of community composition uniqueness of a site compared to regionally sampled sites. LCBD can fluctuate among seasons and ecoregions according to site characteristics, species dispersal abilities, and biotic interactions. In this context, we examined anuran seasonal patterns of LCBD in different ecoregions of Western Brazil, and assessed their correlation with species richness and if environmental (climatic variables, pond area and ecoregions) and/or spatial predictors (spatial configuration of sampling sites captured by distance-based Moran's Eigenvector Maps) would drive patterns of LCBD. We sampled anurans in 19 ponds in different ecoregions in the Mato Grosso do Sul state, Western Brazil, during one dry and one rainy season. We found that LCBD patterns were similar between seasons with sites tending to contribute in the same way for community composition uniqueness during the dry and rainy season. Among studied ecoregions, Cerrado showed higher LCBD values in both seasons. In addition, LCBD was negatively correlated with species richness in the dry season. We also found that LCBD variation was explained by ecoregion in the dry season, but in the rainy season both environmental and spatial global models were non-significant. Our results reinforce the compositional uniqueness of the Cerrado ecoregion when compared to the other ecoregions in both seasons, which may be caused by the presence of species with different requirements that tolerate different conditions caused by seasonality.


Assuntos
Anuros/fisiologia , Ecótipo , Estações do Ano , Animais , Brasil , Tempo (Meteorologia)
6.
Am Nat ; 196(2): 169-179, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32673088

RESUMO

Competition over mates is a powerful force shaping trait evolution. For instance, better cognitive abilities may be beneficial in male-male competition and thus be selected for by intrasexual selection. Alternatively, investment in physical attributes favoring male performance in competition for mates may lower the resources available for brain development, and more intense male mate competition would coincide with smaller brains. To date, only indirect evidence for such relationships exists, and most studies are heavily biased toward primates and other homoeothermic vertebrates. We tested the association between male brain size (relative to body size) and male-male competition across N=30 species of Chinese anurans. Three indicators of the intensity of male mate competition-operational sex ratio (OSR), spawning-site density, and male forelimb muscle mass-were positively associated with relative brain size, whereas the absolute spawning group size was not. The relationship with the OSR and male forelimb muscle mass was stronger for the male than for the female brains. Taken together, our findings suggest that the increased cognitive abilities of larger brains are beneficial in male-male competition. This study adds taxonomic breadth to the mounting evidence for a prominent role of sexual selection in vertebrate brain evolution.


Assuntos
Anuros/anatomia & histologia , Anuros/fisiologia , Encéfalo/anatomia & histologia , Comportamento Competitivo , Animais , Comportamento Animal/fisiologia , Feminino , Membro Anterior/anatomia & histologia , Masculino , Músculo Esquelético/anatomia & histologia , Tamanho do Órgão , Reprodução , Caracteres Sexuais
7.
PLoS One ; 15(7): e0223080, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32639962

RESUMO

Recent reviews on sexual dichromatism in frogs included Mannophryne trinitatis as the only example they could find of dynamic dichromatism (males turn black when calling) within the family Aromobatidae and found no example of ontogenetic dichromatism in this group. We demonstrate ontogenetic dichromatism in M. trinitatis by rearing post-metamorphic froglets to near maturity: the throats of all individuals started as grey coloured; at around seven weeks, the throat became pale yellow in some, and more strongly yellow as development proceeded; the throats of adults are grey in males and variably bright yellow in females, backed by a dark collar. We demonstrated the degree of throat colour variability by analysing a large sample of females. The red: green (R:G) ratio ranged from ~1.1 to 1.4, reflecting variation from yellow to yellow/orange, and there was also variation in the tone and width of the dark collar, and in the extent to which the yellow colouration occurred posterior to the collar. Female M. trinitatis are known to be territorial in behaviour. We show a positive relationship between throat colour (R:G ratio) and escape performance, as a proxy for quality. Our field observations on Tobago's M. olmonae showed variability in female throat colour and confirmed that males in this species also turn black when calling. Our literature review of the 20 Mannophryne species so far named showed that all females have yellow throats with dark collars, and that male colour change to black when calling has been reported in eight species; in the remaining 12 species, descriptions of males calling are usually lacking so far. We predict that both dynamic and ontogenetic sexual dichromatism are universal in this genus and provide discussion of the ecological role of dichromatism in this genus of predominantly diurnal, non-toxic frogs, with strong paternal care of offspring.


Assuntos
Anuros/fisiologia , Caracteres Sexuais , Animais , Anuros/crescimento & desenvolvimento , Comportamento Animal , Cor , Feminino , Masculino , Faringe/fisiologia
8.
Nat Commun ; 11(1): 3608, 2020 07 17.
Artigo em Inglês | MEDLINE | ID: mdl-32681028

RESUMO

Invasive predators can exert strong selection on native populations. If selection is strong enough, populations could lose the phenotypic variation caused by adaptation to heterogeneous environments. We compare frog tadpoles prior to and 14 years following invasion by crayfish. Prior to the invasion, populations differed in their intrinsic developmental rate, with tadpoles from cold areas reaching metamorphosis sooner than those from warm areas. Following the invasion, tadpoles from invaded populations develop faster than those from non-invaded populations. This ontogenetic shift overwhelmed the intraspecific variation between populations in a few generations, to the point where invaded populations develop at a similar rate regardless of climate. Rapid development can have costs, as fast-developing froglets have a smaller body size and poorer jumping performance, but compensatory growth counteracts some costs of development acceleration. Strong selection by invasive species can disrupt local adaptations by dampening intraspecific phenotypic variation, with complex consequences on lifetime fitness.


Assuntos
Espécies Introduzidas , Larva/fisiologia , Aclimatação , Adaptação Fisiológica , Animais , Anuros/classificação , Anuros/crescimento & desenvolvimento , Anuros/fisiologia , Astacoidea/fisiologia , Tamanho Corporal , Clima , Larva/classificação , Larva/crescimento & desenvolvimento
9.
Proc Natl Acad Sci U S A ; 117(31): 18574-18581, 2020 08 04.
Artigo em Inglês | MEDLINE | ID: mdl-32661155

RESUMO

Many vertebrates have distinctive blue-green bones and other tissues due to unusually high biliverdin concentrations-a phenomenon called chlorosis. Despite its prevalence, the biochemical basis, biology, and evolution of chlorosis are poorly understood. In this study, we show that the occurrence of high biliverdin in anurans (frogs and toads) has evolved multiple times during their evolutionary history, and relies on the same mechanism-the presence of a class of serpin family proteins that bind biliverdin. Using a diverse combination of techniques, we purified these serpins from several species of nonmodel treefrogs and developed a pipeline that allowed us to assemble their complete amino acid and nucleotide sequences. The described proteins, hereafter named biliverdin-binding serpins (BBS), have absorption spectra that mimic those of phytochromes and bacteriophytochromes. Our models showed that physiological concentration of BBSs fine-tune the color of the animals, providing the physiological basis for crypsis in green foliage even under near-infrared light. Additionally, we found that these BBSs are most similar to human glycoprotein alpha-1-antitrypsin, but with a remarkable functional diversification. Our results present molecular and functional evidence of recurrent evolution of chlorosis, describe a biliverdin-binding protein in vertebrates, and introduce a function for a member of the serpin superfamily, the largest and most ubiquitous group of protease inhibitors.


Assuntos
Anuros/fisiologia , Biliverdina/metabolismo , Serpinas/metabolismo , Pigmentação da Pele/fisiologia , Animais , Anuros/classificação , Anuros/genética , Biliverdina/química , Mimetismo Biológico/fisiologia , Serpinas/química , Serpinas/genética , Pigmentação da Pele/genética
10.
Am Nat ; 195(5): E132-E149, 2020 05.
Artigo em Inglês | MEDLINE | ID: mdl-32364784

RESUMO

In animals, bright colors often evolve to mimic other species when a resemblance is selectively favored. Understanding the proximate mechanisms underlying such color mimicry can give insights into how mimicry evolves-for example, whether color convergence evolves from a shared set of mechanisms or through the evolution of novel color production mechanisms. We studied color production mechanisms in poison frogs (Dendrobatidae), focusing on the mimicry complex of Ranitomeya imitator. Using reflectance spectrometry, skin pigment analysis, electron microscopy, and color modeling, we found that the bright colors of these frogs, both within and outside the mimicry complex, are largely structural and produced by iridophores but that color production depends crucially on interactions with pigments. Color variation and mimicry are regulated predominantly by iridophore platelet thickness and, to a lesser extent, concentration of the red pteridine pigment drosopterin. Compared with each of the four morphs of model species that it resembles, R. imitator displays greater variation in both structural and pigmentary mechanisms, which may have facilitated phenotypic divergence in this species. Analyses of nonmimetic dendrobatids in other genera demonstrate that these mechanisms are widespread within the family and that poison frogs share a complex physiological "color palette" that can produce diverse and highly reflective colors.


Assuntos
Anuros/fisiologia , Evolução Biológica , Pigmentação , Pigmentos Biológicos/fisiologia , Animais , Cor , Microscopia Eletrônica de Transmissão/veterinária , Pele/ultraestrutura , Pigmentação da Pele/fisiologia
11.
Am Nat ; 195(5): 927-933, 2020 05.
Artigo em Inglês | MEDLINE | ID: mdl-32364791

RESUMO

Mating signals have evolved to attract target receivers, even to the point of exploiting receivers through perceptual manipulation. Signals, however, can also expose signalers to nontarget receivers, including predators and parasites, and thus have also evolved to decrease enemy attraction. Here we show that male tree frogs (Smilisca sila) reduce their attractiveness to eavesdropping enemies (bats and midges) by overlapping their calls at near-perfect synchrony with the calls of neighboring conspecifics. By producing calls that closely follow those of other males, synchronizing S. sila take advantage of an auditory illusion where enemies are more attracted to the leading call. Female S. sila, however, are less susceptible to this illusion. Thus, synchronization among signaling males can result in acoustic crypsis from predators without affecting female attraction. Given the widespread use of conspicuous mating signals and eavesdropping enemies, perceptual exploitation of eavesdroppers is likely a common driver of signal evolution.


Assuntos
Anuros/fisiologia , Quirópteros/fisiologia , Dípteros/fisiologia , Comportamento Predatório , Vocalização Animal , Animais , Feminino , Ilusões , Masculino
12.
Sci Rep ; 10(1): 8627, 2020 05 25.
Artigo em Inglês | MEDLINE | ID: mdl-32451461

RESUMO

Audial surveys of anuran amphibians (frogs, toads and similar) are cost-effective and allow for the coverage of large areas, but they are usually regarded as unsuitable for population size estimations due to imperfect detection. Our study demonstrated a method for obtaining minimum adult population size estimates from vocalising anuran counts by using sex ratios, life history and vocalising behaviour parameters from other studies. We collected data from 2016 to 2018 for seven taxa on 65 plots (each 25 km2) representing the entirety of Latvia. Among taxa, average breeding waterbody audible detection probabilities ranged from 0.56 to 0.88 per plot, minimum adult frog density (MAFD) estimates were from 12.0 to 51.7 individuals per km2, but the estimated fraction of population covered by MAFD varied from 57 to 86%. The least accurate density estimates were in taxa with brief calling activity and quiet mating calls (Rana temporaria), and in taxa with a calling activity dependent on the numbers of males in a pond (Bufo bufo). Our study suggests that lek-breeders would be more suitable than explosive-breeding taxa for minimum population size estimates from audial data. The use of MAFD allowed for coarse minimum population size estimates for the entire country from the audial monitoring data, these ranged from 3.7 ± 0.5 thousand (Bombina bombina) to 1.64 ± 0.47 million (B.bufo) adults.


Assuntos
Anuros/fisiologia , Densidade Demográfica , Animais , Cruzamento , Masculino , Estações do Ano , Vocalização Animal
13.
J Parasitol ; 106(3): 334-340, 2020 06 01.
Artigo em Inglês | MEDLINE | ID: mdl-32369595

RESUMO

We investigated the mean abundance of helminths and analyzed helminth composition and structure at the infracommunity and component community levels for 3 anuran species (Pleurodema diplolister, Rhinella jimi, and Rhinella granulosa) from the Caatingas, a semiarid Brazilian region characterized by accentuated seasonality and unpredictability of rains. Data were collected during the reproductive period and during drought, when P. diplolister estivated buried underground but R. jimi and R. granulosa remained foraging actively. We expected higher parasitological parameters during the reproductive period when compared to drought for these 3 anurans. We also expected higher parasite infection in the Rhinella species and higher similarity between their helminth parasite communities when compared to the estivating species, P. diplolister. Contrary to our hypothesis, the season was not related to parasite community structure. As predicted, the Rhinella toads shared more similar species composition of parasite communities. These similarities in the composition of the parasite community between Rhinella species could be due to similar temporal/spatial patterns of activity and phylogenetic proximity. Pleurodema diplolister hosted a more restricted helminth fauna, a result that might be associated with estivation restricting the temporal window available to acquire parasites. This study also presents new helminth fauna records for R. jimi and P. diplolister, and the first helminth fauna record of R. granulosa from the Caatingas in semiarid Brazil.


Assuntos
Anuros/parasitologia , Helmintíase Animal/parasitologia , Animais , Anuros/fisiologia , Brasil/epidemiologia , Secas , Helmintíase Animal/epidemiologia , Masculino , Chuva , Reprodução , Estações do Ano
14.
Proc Natl Acad Sci U S A ; 117(23): 12885-12890, 2020 06 09.
Artigo em Inglês | MEDLINE | ID: mdl-32457164

RESUMO

Camouflage patterns prevent detection and/or recognition by matching the background, disrupting edges, or mimicking particular background features. In variable habitats, however, a single pattern cannot match all available sites all of the time, and efficacy may therefore be reduced. Active color change provides an alternative where coloration can be altered to match local conditions, but again efficacy may be limited by the speed of change and range of patterns available. Transparency, on the other hand, creates high-fidelity camouflage that changes instantaneously to match any substrate but is potentially compromised in terrestrial environments where image distortion may be more obvious than in water. Glass frogs are one example of terrestrial transparency and are well known for their transparent ventral skin through which their bones, intestines, and beating hearts can be seen. However, sparse dorsal pigmentation means that these frogs are better described as translucent. To investigate whether this imperfect transparency acts as camouflage, we used in situ behavioral trials, visual modeling, and laboratory psychophysics. We found that the perceived luminance of the frogs changed depending on the immediate background, lowering detectability and increasing survival when compared to opaque frogs. Moreover, this change was greatest for the legs, which surround the body at rest and create a diffuse transition from background to frog luminance rather than a sharp, highly salient edge. This passive change in luminance, without significant modification of hue, suggests a camouflage strategy, "edge diffusion," distinct from both transparency and active color change.


Assuntos
Adaptação Biológica/fisiologia , Anuros/fisiologia , Reconhecimento Visual de Modelos/fisiologia , Pigmentação da Pele/fisiologia , Animais , Cor , Simulação por Computador , Ecossistema , Furões/fisiologia , Humanos , Modelos Biológicos , Comportamento Predatório/fisiologia
15.
Sci Rep ; 10(1): 6838, 2020 04 22.
Artigo em Inglês | MEDLINE | ID: mdl-32321935

RESUMO

Life history theory predicts that animals often produce fewer offspring of larger size and indicate a stronger trade-off between the number and size of offspring to cope with increasing environmental stress. In order to evaluate this prediction, we tested the life history characteristics of Bufo minshanicus at eight different altitudes on the eastern Tibetan Plateau, China. Our results revealed a positive correlation between female SVL and clutch size or egg size, revealing that larger females produce more and larger eggs. However, high-altitude toads seem to favor more offspring and smaller egg sizes when removing the effect of female SVL, which is counter to theoretical predictions. In addition, there was an overall significantly negative relationship between egg size and clutch size, indicative of a trade-off between egg size and fecundity. Therefore, we suggest that higher fecundity, rather than larger egg size, is a more effective reproductive strategy for this species of anuran living at high-altitude environments.


Assuntos
Anuros , Tamanho da Ninhada/fisiologia , Zigoto , Animais , Anuros/anatomia & histologia , Anuros/fisiologia , Feminino , Fertilidade/fisiologia , Tibet , Zigoto/citologia , Zigoto/fisiologia
16.
Biochem Pharmacol ; 177: 113976, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-32305433

RESUMO

The progesterone receptor (PR) mediates progesterone regulation of female reproductive physiology, as well as gene transcription in non-reproductive tissues, such as brain, bone, lung and vasculature, in both women and men. An unusual property of progesterone is its high affinity for the mineralocorticoid receptor (MR), which regulates electrolyte transport in the kidney in humans and other terrestrial vertebrates. In humans, rats, alligators and frogs, progesterone antagonizes activation of the MR by aldosterone, the physiological mineralocorticoid in terrestrial vertebrates. In contrast, in elephant shark, ray-finned fishes and chickens, progesterone activates the MR. Interestingly, cartilaginous fishes and ray-finned fishes do not synthesize aldosterone, raising the question of which steroid(s) activate the MR in cartilaginous fishes and ray-finned fishes. The simpler synthesis of progesterone, compared to cortisol and other corticosteroids, makes progesterone a candidate physiological activator of the MR in elephant sharks and ray-finned fishes. Elephant shark and ray-finned fish MRs are expressed in diverse tissues, including heart, brain and lung, as well as, ovary and testis, two reproductive tissues that are targets for progesterone, which together suggests a multi-faceted physiological role for progesterone activation of the MR in elephant shark and ray-finned fish. The functional consequences of progesterone as an antagonist of some terrestrial vertebrate MRs and as an agonist of fish and chicken MRs are not fully understood. The physiological activities of progesterone through binding to vertebrate MRs merits further investigation.


Assuntos
Rim/efeitos dos fármacos , Ovário/metabolismo , Progesterona/metabolismo , Receptores de Mineralocorticoides/metabolismo , Aldosterona/metabolismo , Jacarés e Crocodilos/classificação , Jacarés e Crocodilos/fisiologia , Sequência de Aminoácidos , Animais , Anuros/classificação , Anuros/fisiologia , Encéfalo/metabolismo , Galinhas/classificação , Galinhas/fisiologia , Feminino , Regulação da Expressão Gênica , Humanos , Hidrocortisona/metabolismo , Rim/metabolismo , Ligantes , Pulmão/metabolismo , Filogenia , Progesterona/farmacologia , Ratos , Receptores de Mineralocorticoides/agonistas , Receptores de Mineralocorticoides/genética , Tubarões/classificação , Tubarões/fisiologia , Transdução de Sinais , Especificidade da Espécie
17.
Sci Rep ; 10(1): 6527, 2020 04 16.
Artigo em Inglês | MEDLINE | ID: mdl-32300179

RESUMO

Artificial light at night (ALAN) is a major form of anthropogenic disturbance. ALAN attracts nocturnal invertebrates, which are a food source for nocturnal predators, including invasive species. Few studies quantify the effects of increased food availablity by ALAN on invasive vertebrate predators, and enhancement of food intake caused by ALAN may also be influenced by various environmental factors, such as proximitity to cities, moon phase, temperature, rainfall and wind speed. Revealing the potential impacts on invasive predators of ALAN-attracted invertebrates, and the influence of other factors on these effects, could provide important insights for the management of these predators. We constructed and supplied with artificial light field enclosures for invasive toads, and placed them at locations with different levels of ambient light pollution, in northeastern Australia. In addition, we determined the effect of rainfall, temperature, wind speed, and lunar phase on food intake in toads. We found that ALAN greatly increased the mass of gut contents of invasive toads compared to controls, but that the effect was increased in dark lunar phases, and when there were low ambient light pollution levels. Effects of rainfall, temperature and wind speed on food intake were comparatively weak. To avoid providing food resources to toads, management of ALAN in rural areas, and during dark lunar phases may be advisable. On the contrary, to effectively capture toads, trapping using lights as lures at such times and places should be more successful.


Assuntos
Anuros/fisiologia , Ingestão de Alimentos/efeitos da radiação , Luz/efeitos adversos , Animais , Austrália , Humanos , Espécies Introduzidas
18.
BMC Genomics ; 21(1): 226, 2020 Mar 12.
Artigo em Inglês | MEDLINE | ID: mdl-32164545

RESUMO

BACKGROUND: Cope's gray treefrog, Dryophytes chrysoscelis, withstands the physiological challenges of corporeal freezing, partly by accumulating cryoprotective compounds of hepatic origin, including glycerol, urea, and glucose. We hypothesized that expression of genes related to cryoprotectant mobilization and stress tolerance would be differentially regulated in response to cold. Using high-throughput RNA sequencing (RNA-Seq), a hepatic transcriptome was generated for D. chrysoscelis, and gene expression was compared among frogs that were warm-acclimated, cold-acclimated, and frozen. RESULTS: A total of 159,556 transcripts were generated; 39% showed homology with known transcripts, and 34% of all transcripts were annotated. Gene-level analyses identified 34,936 genes, 85% of which were annotated. Cold acclimation induced differential expression both of genes and non-coding transcripts; freezing induced few additional changes. Transcript-level analysis followed by gene-level aggregation revealed 3582 differentially expressed genes, whereas analysis at the gene level revealed 1324 differentially regulated genes. Approximately 3.6% of differentially expressed sequences were non-coding and of no identifiable homology. Expression of several genes associated with cryoprotectant accumulation was altered during cold acclimation. Of note, glycerol kinase expression decreased with cold exposure, possibly promoting accumulation of glycerol, whereas glucose export was transcriptionally promoted by upregulation of glucose-6-phosphatase and downregulation of genes of various glycolytic enzymes. Several genes related to heat shock protein response, DNA repair, and the ubiquitin proteasome pathway were upregulated in cold and frozen frogs, whereas genes involved in responses to oxidative stress and anoxia, both potential sources of cellular damage during freezing, were downregulated or unchanged. CONCLUSION: Our study is the first to report transcriptomic responses to low temperature exposure in a freeze-tolerant vertebrate. The hepatic transcriptome of Dryophytes chrysoscelis is responsive to cold and freezing. Transcriptomic regulation of genes related to particular pathways, such as glycerol biosynthesis, were not all regulated in parallel. The physiological demands associated with cold and freezing, as well as the transcriptomic responses observed in this study, are shared with several organisms that face similar ecophysiological challenges, suggesting common regulatory mechanisms. The role of transcriptional regulation relative to other cellular processes, and of non-coding transcripts as elements of those responses, deserve further study.


Assuntos
Aclimatação , Anuros/fisiologia , Perfilação da Expressão Gênica/veterinária , Fígado/química , Animais , Anuros/genética , Resposta ao Choque Frio , Regulação da Expressão Gênica , Redes Reguladoras de Genes , Sequenciamento de Nucleotídeos em Larga Escala , Análise de Sequência de RNA
20.
Science ; 367(6484): 1377-1379, 2020 03 20.
Artigo em Inglês | MEDLINE | ID: mdl-32193328

RESUMO

Hybridization-interbreeding between species-is generally thought to occur randomly between members of two species. Contrary to expectation, female plains spadefoot toads (Spea bombifrons) can increase their evolutionary fitness by preferentially mating with high-quality males of another species, the Mexican spadefoot toad (Spea multiplicata). Aspects of Mexican spadefoot males' mating calls predict their hybrid offspring's fitness, and plains spadefoot females prefer Mexican spadefoot males on the basis of these attributes, but only in populations and ecological conditions where hybridization is adaptive. By selecting fitness-enhancing mates of another species, females increase hybridization's benefits and exert sexual selection across species. Nonrandom mating between species can thereby increase the potential for adaptive gene flow between species so that adaptive introgression is not simply happenstance.


Assuntos
Anuros/fisiologia , Hibridização Genética , Preferência de Acasalamento Animal , Reprodução , Seleção Genética , Animais , Anuros/genética , Ecossistema , Feminino , Aptidão Genética , Masculino , Vocalização Animal , Água
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