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Richard P. Elinson - One of the best experts on this subject based on the ideXlab platform.
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commitment to nutritional endoderm in Eleutherodactylus coqui involves altered nodal signaling and global transcriptional repression
Journal of Experimental Zoology, 2014Co-Authors: Suman Chatterjee, Richard P. ElinsonAbstract:The vegetal cells of a Xenopus laevis embryo commit to mesendoderm via the Nodal-signaling pathway. In the direct developing frog Eleutherodactylus coqui, mesendoderm is specified at the marginal zone of the early gastrula, and vegetal core cells transform into nutritional endoderm. Nutritional endoderm, a novel tissue, consists of transient, yolky cells that provide nutrition but remain undifferentiated. We report a dual regulation for the generation of nutritional endoderm. First, differential expressions of the Nodal-signal transducers Smad2 and Smad4 were observed during early gastrulation between the marginal zone and the vegetal core cells. Although EcSmad2 RNA as well as total and activated Smad2 protein were detected in the vegetal core, Smad4 protein was expressed less in vegetal core during early gastrulation. Only 12% and 50% of vegetal core cells were positive for nuclear Smad2 and Smad4 signals respectively compared to 100% of marginal zone cells. These results suggest a signaling disruption in the vegetal core. Second, vegetal core cells were transcriptionally repressed. At the blastula stage, both marginal zone and vegetal core cells were transcriptionally silent, but during early gastrulation, only marginal zone cells became transcriptionally active. This indicates the occurrence of a mid-blastula transition in the marginal zone by early gastrulation, but global transcriptional repression persisted in the vegetal core and its derivative, nutritional endoderm, throughout development. We have described a novel mechanism, which prevents differentiation of the vegetal core through differential Nodal-signaling and global transcriptional repression. J. Exp. Zool. (Mol. Dev. Evol.) 322B: 27–44, 2014. © 2013 Wiley Periodicals, Inc.
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Characterization of the nutritional endoderm in the direct developing frog Eleutherodactylus coqui
Development Genes and Evolution, 2013Co-Authors: Uma Karadge, Richard P. ElinsonAbstract:Unlike Xenopus laevis , Eleutherodactylus coqui develops without a tadpole. The yolk-rich vegetal region of the embryo forms a transient nutritive tissue, the nutritional endoderm (NE). The definitive endoderm (DE) in E . coqui comes from cells closer to the animal pole in contrast to its vegetal origin in X . laevis . RNA important for initiating the endoderm specification network is absent in presumptive NE cells, raising the question whether signaling occurs in them. We explored the nature of NE and asked how differences between NE and DE cells arise. We identified differences between NE and DE that first become evident at gastrula, when NE cells become multinucleated. Nuclear β-catenin, an essential cofactor of sox 17, important for endoderm formation in X . laevis , is present in NE and DE at gastrula but remains in NE long after it is not seen in DE. We cloned E . coqui homologs of TGFβs activin b and derriere and provide evidence for their maternal expression. We also detected activin b and derriere RNAs in NE at gastrula and show that NE possesses some mesoderm-inducing activity, but it is delayed with respect to DE. Our findings indicate that altered development of NE begins at gastrula. RNAs important for mesendoderm induction and some mesoderm-inducing activity are present in NE.
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RESEARCH Open Access Germ plasm in Eleutherodactylus coqui, a direct developing frog with large eggs
2013Co-Authors: Richard P. Elinson, Michelle C Sabo, Cara Fisher, Takeshi Yamaguchi, Hidefumi Orii, Kimberly NathAbstract:Background: RNAs for embryo patterning and for germ cell specification are localized to the vegetal cortex of the oocyte of Xenopus laevis. In oocytes of the direct developing frog Eleutherodactylus coqui, orthologous RNAs for patterning are not localized, raising the question as to whether RNAs and other components of germ plasm are localized in this species. Methods: To identify germ plasm, E. coqui embryos were stained with DiOC6(3) or examined by in situ hybridization for dazl and DEADSouth RNAs. The cDNAs for the E. coqui orthologues were cloned by RT-PCR using degenerate primers. To examine activity of the E. coqui orthologues, RNAs, made from constructs of their 3’UTRs with mCherry, were injected into X. laevis embryos. Results: Both DiOC6(3) and dazl and DEADSouth in situs identified many small islands at the vegetal surface of cleaving E. coqui embryos, indicative of germ plasm. Dazl was also expressed in primordial germ cells in the genital ridge. The 3’UTRs of E. coqui dazl and DEADSouth directed primordial germ cell specific protein synthesis in X. laevis. Conclusions: E. coqui utilizes germ plasm with RNAs localized to the vegetal cortex to specify primordial germ cells. The large number of germ plasm islands suggests that an increase in the amount of germ plasm wa
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expression of cyclin d1 cyclin d2 and n myc in embryos of the direct developing frog Eleutherodactylus coqui with a focus on limbs
Gene Expression Patterns, 2013Co-Authors: Kimberly Nath, Cara Fisher, Richard P. ElinsonAbstract:Species of frogs that develop directly have removed the tadpole from their ontogeny and form adult structures precociously. To see whether cell cycle regulators could be involved in this altered embryogenesis, we examined the expression of ccnd1, ccnd2, and mycn in embryos of the direct developing frog, Eleutherodactylus coqui. Notable differences compared to embryos of Xenopus laevis, a species with a tadpole, included prominent expression of ccnd2 in the midbrain and ccnd1 in the mandibular neural crest. The former may contribute to the precocious appearance of the adult-type visual system and the latter to the adult-type jaw. Large domains of ccnd2 and mycn presage the early appearance of limb buds, and ccnd1 and mycn are implicated in digit development.
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Germ plasm in Eleutherodactylus coqui, a direct developing frog with large eggs
EvoDevo, 2011Co-Authors: Richard P. Elinson, Michelle C Sabo, Cara Fisher, Takeshi Yamaguchi, Hidefumi Orii, Kimberly NathAbstract:Background RNAs for embryo patterning and for germ cell specification are localized to the vegetal cortex of the oocyte of Xenopus laevis . In oocytes of the direct developing frog Eleutherodactylus coqui , orthologous RNAs for patterning are not localized, raising the question as to whether RNAs and other components of germ plasm are localized in this species. Methods To identify germ plasm, E. coqui embryos were stained with DiOC_6(3) or examined by in situ hybridization for dazl and DEADSouth RNAs. The cDNAs for the E. coqui orthologues were cloned by RT-PCR using degenerate primers. To examine activity of the E. coqui orthologues, RNAs, made from constructs of their 3'UTRs with mCherry , were injected into X. laevis embryos. Results Both DiOC_6(3) and dazl and DEADSouth in situs identified many small islands at the vegetal surface of cleaving E. coqui embryos, indicative of germ plasm. Dazl was also expressed in primordial germ cells in the genital ridge. The 3'UTRs of E. coqui dazl and DEADSouth directed primordial germ cell specific protein synthesis in X. laevis . Conclusions E. coqui utilizes germ plasm with RNAs localized to the vegetal cortex to specify primordial germ cells. The large number of germ plasm islands suggests that an increase in the amount of germ plasm was important in the evolution of the large E. coqui egg.
James Hanken - One of the best experts on this subject based on the ideXlab platform.
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evolutionary conservation of thyroid hormone receptor and deiodinase expression dynamics in ovo in a direct developing frog Eleutherodactylus coqui
Frontiers in Endocrinology, 2019Co-Authors: Mara Laslo, Robert J Denver, James HankenAbstract:Direct development is a reproductive mode in amphibians that has evolved independently from the ancestral biphasic life history in at least a dozen anuran lineages. Most direct-developing frogs, including the Puerto Rican coqui, Eleutherodactylus coqui, lack a free-living aquatic larva and instead hatch from terrestrial eggs as miniature adults. Their embryonic development includes the transient formation of many larval-specific features and the formation of adult-specific features that typically form postembryonically—during metamorphosis—in indirect-developing frogs. We found that pre-hatching developmental patterns of thyroid hormone receptors alpha (thra) and beta (thrb) and deiodinases type II (dio2) and type III (dio3) mRNAs in E. coqui limb and tail are conserved relative to those seen during metamorphosis in indirect-developing frogs. Additionally, thra, thrb, and dio2 mRNAs are expressed in the limb before formation of the embryonic thyroid gland. Liquid-chromatography mass-spectrometry revealed that maternally derived thyroid hormone is present throughout early embryogenesis, including stages of digit formation that occur prior to the increase in embryonically produced thyroid hormone. Eleutherodactylus coqui embryos take up much less 3,5,3’-triiodothyronine (T3) from the environment compared with X. tropicalis tadpoles. However, E. coqui tissue explants mount robust and direct gene expression responses to exogenous T3 similar to those seen in metamorphosing species. The presence of key components of the thyroid axis in the limb and the ability of limb tissue to respond to T3 suggest that thyroid hormone-mediated limb development may begin prior to thyroid gland formation. Thyroid hormone-dependent limb development and tail resorption characteristic of metamorphosis in indirect-developing anurans are evolutionarily conserved, but they occur instead in ovo in E. coqui.
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Table_1_Evolutionary Conservation of Thyroid Hormone Receptor and Deiodinase Expression Dynamics in ovo in a Direct-Developing Frog, Eleutherodactylus coqui.XLSX
2019Co-Authors: Mara Laslo, Robert J Denver, James HankenAbstract:Direct development is a reproductive mode in amphibians that has evolved independently from the ancestral biphasic life history in at least a dozen anuran lineages. Most direct-developing frogs, including the Puerto Rican coquí, Eleutherodactylus coqui, lack a free-living aquatic larva and instead hatch from terrestrial eggs as miniature adults. Their embryonic development includes the transient formation of many larval-specific features and the formation of adult-specific features that typically form postembryonically—during metamorphosis—in indirect-developing frogs. We found that pre-hatching developmental patterns of thyroid hormone receptors alpha (thra) and beta (thrb) and deiodinases type II (dio2) and type III (dio3) mRNAs in E. coqui limb and tail are conserved relative to those seen during metamorphosis in indirect-developing frogs. Additionally, thra, thrb, and dio2 mRNAs are expressed in the limb before formation of the embryonic thyroid gland. Liquid-chromatography mass-spectrometry revealed that maternally derived thyroid hormone is present throughout early embryogenesis, including stages of digit formation that occur prior to the increase in embryonically produced thyroid hormone. Eleutherodactylus coqui embryos take up much less 3,5,3′-triiodothyronine (T3) from the environment compared with X. tropicalis tadpoles. However, E. coqui tissue explants mount robust and direct gene expression responses to exogenous T3 similar to those seen in metamorphosing species. The presence of key components of the thyroid axis in the limb and the ability of limb tissue to respond to T3 suggest that thyroid hormone-mediated limb development may begin prior to thyroid gland formation. Thyroid hormone-dependent limb development and tail resorption characteristic of metamorphosis in indirect-developing anurans are evolutionarily conserved, but they occur instead in ovo in E. coqui.
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Data_Sheet_1_Evolutionary Conservation of Thyroid Hormone Receptor and Deiodinase Expression Dynamics in ovo in a Direct-Developing Frog, Eleutherodactylus coqui.pdf
2019Co-Authors: Mara Laslo, Robert J Denver, James HankenAbstract:Direct development is a reproductive mode in amphibians that has evolved independently from the ancestral biphasic life history in at least a dozen anuran lineages. Most direct-developing frogs, including the Puerto Rican coquí, Eleutherodactylus coqui, lack a free-living aquatic larva and instead hatch from terrestrial eggs as miniature adults. Their embryonic development includes the transient formation of many larval-specific features and the formation of adult-specific features that typically form postembryonically—during metamorphosis—in indirect-developing frogs. We found that pre-hatching developmental patterns of thyroid hormone receptors alpha (thra) and beta (thrb) and deiodinases type II (dio2) and type III (dio3) mRNAs in E. coqui limb and tail are conserved relative to those seen during metamorphosis in indirect-developing frogs. Additionally, thra, thrb, and dio2 mRNAs are expressed in the limb before formation of the embryonic thyroid gland. Liquid-chromatography mass-spectrometry revealed that maternally derived thyroid hormone is present throughout early embryogenesis, including stages of digit formation that occur prior to the increase in embryonically produced thyroid hormone. Eleutherodactylus coqui embryos take up much less 3,5,3′-triiodothyronine (T3) from the environment compared with X. tropicalis tadpoles. However, E. coqui tissue explants mount robust and direct gene expression responses to exogenous T3 similar to those seen in metamorphosing species. The presence of key components of the thyroid axis in the limb and the ability of limb tissue to respond to T3 suggest that thyroid hormone-mediated limb development may begin prior to thyroid gland formation. Thyroid hormone-dependent limb development and tail resorption characteristic of metamorphosis in indirect-developing anurans are evolutionarily conserved, but they occur instead in ovo in E. coqui.
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development of neuroendocrine components of the thyroid axis in the direct developing frog Eleutherodactylus coqui formation of the median eminence and onset of pituitary tsh production
General and Comparative Endocrinology, 2015Co-Authors: Bryce Evans, David H Jennings, James HankenAbstract:Direct-developing frogs lack, wholly or in part, a wide range of larval features found in metamorphosing species and form adult-specific features precociously, during embryogenesis. Most information on thyroid regulation of direct development relies on hormone manipulations; the ontogeny of many thyroid axis components has not been fully described. This analysis examines differentiation of the median eminence of the hypothalamus and production of thyroid-stimulating hormone (TSH) by the pituitary of the direct-developing frog Eleutherodactylus coqui. The median eminence is established two-thirds of the way through embryogenesis. Cells immunoreactive to human TSHβ antibodies are first detected during embryogenesis and quantitative changes in TSHβ-IR cells resemble those in metamorphosing amphibians. Formation of the median eminence of the hypothalamus and TSHβ production by the pituitary precede or coincide with morphological changes during embryogenesis that occur during metamorphosis in biphasic anurans. Thus, while the onset of neuroendocrine regulation has changed during the evolution of direct development, it is likely that these thyroid axis components still mediate the formation of adult features.
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molecular anatomy of the developing limb in the coqui frog Eleutherodactylus coqui
Evolution & Development, 2011Co-Authors: Joshua B Gross, James Hanken, Ryan Kerney, Clifford J TabinAbstract:SUMMARY The vertebrate limb demonstrates remark- able similarity in basic organization across phylogenetically disparate groups. To gain further insight into how this mor- phological similarity is maintained in different developmental contexts, we explored the molecular anatomy of size-reduced embryos of the Puerto Rican coqufrog, Eleutherodactylus coqui. This animal demonstrates direct development, a life- history strategy marked by rapid progression from egg to adult and absence of a free-living, aquatic larva. Nonethe- less, coqu´o exhibits a basal anuran limb structure, with four toes on the forelimb and five toes on the hind limb. We in- vestigated the extent to which coqulimb bud development conforms to the model of limb development derived from am- niote studies. Toward this end, we characterized dynamic pat- terns of expression for 13 critical patterning genes across three principle stages of limb development. As expected, most genes demonstrate expression patterns that are es- sentially unchanged compared to amniote species. For ex- ample, we identified an EcFgf8-expression domain within the apical ectodermal ridge (AER). This expression pattern de- fines a putatively functional AER signaling domain, despite the absence of a morphological ridge in coqu´o embryos. However, two genes, EcMeis2 and EcAlx4, demonstrate al- tered domains of expression, which imply a potential shift in gene function between coqufrogs and amniote model sys- tems. Unexpectedly, several genes thought to be critical for limb patterning in other systems, including EcFgf4, EcWnt3a, EcWnt7a, and EcGremlin, demonstrated no evident expres- sion pattern in the limb at the three stages we analyzed. The absence of EcFgf4 and EcWnt3a expression during limb patterning is perhaps not surprising, given that neither gene is critical for proper limb development in the mouse, based on knockout and expression analyses. In contrast, absence of EcWnt7a and EcGremlin is surprising, given that expres- sion of these molecules appears to be absolutely essential in all other model systems so far examined. Although this analysis substantiates the existence of a core set of an- cient limb-patterning molecules, which likely mediate iden- tical functions across highly diverse vertebrate forms, it also reveals remarkable evolutionary flexibility in the genetic con- trol of a conserved morphological pattern across evolutionary time.
Karen H Beard - One of the best experts on this subject based on the ideXlab platform.
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temporal foraging patterns of nonnative coqui frogs Eleutherodactylus coqui in hawaii
Journal of Herpetology, 2016Co-Authors: Arthur Wallis, Robyn L Smith, Karen H BeardAbstract:Abstract The Puerto Rican coqui Frog (Eleutherodactylus coqui) is a nocturnal, invasive species that was introduced into Hawaii in the 1980s. Because they reach extremely high densities (up to 90,000 frogs/ha), they have the potential to affect invertebrate prey communities. Previously, researchers used frogs collected only at night to characterize their prey. Because coquis use retreat sites near the forest floor during the day and understory perch sites at night, frogs collected at night might show different amounts and types of prey than would frogs collected in the morning. We analyzed stomach contents of 435 frogs collected in the morning (0300–0600 h) and at night (1900–2200 h) from five sites on the island of Hawaii. Frogs collected in the morning had 1.7 times more prey items and 2.1 times greater prey volume than those collected at night; however, prey composition did not differ between morning- and evening-collected frogs. Across sites, Formicidae (ants) and Amphipoda (amphipods) were the domina...
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clinal variation in calls of native and introduced populations of Eleutherodactylus coqui
Copeia, 2011Co-Authors: Eric M Oneill, Karen H BeardAbstract:We determined whether Eleutherodactylus coqui exhibits clinal variation in male advertisement call parameters across its native Puerto Rico and introduced range of Hawaii. In the laboratory, we determined whether clinal variation in call parameters were a result of body size or temperature. Calls correlate with elevation in both Puerto Rico and Hawaii in the following ways: negative for fundamental frequency of each call syllable (Co and Qui), positive with the duration of each call, negative with call rate (calls per minute), and no relationship with call intensity. In the laboratory, we found the negative relationship between elevation and call frequency was best explained by larger body sizes at higher elevations, and that the positive and negative relationships between elevation and call duration, and elevation and call rate, respectively, were best explained by lower temperatures at higher elevations. While frogs in Hawaii exhibited the same relationships between elevation and call parameters found i...
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genetic basis of a color pattern polymorphism in the coqui frog Eleutherodactylus coqui
Journal of Heredity, 2010Co-Authors: Eric M Oneill, Karen H BeardAbstract:Many species of frog exhibit striking color and pattern polymorphisms, but the genetic bases of these traits are not known for most species. The coqui frog, Eleutherodactylus coqui, a species endemic to the island of Puerto Rico, exhibits a wide variety of color and pattern polymorphisms including 4 discrete stripe patterns on its dorsal surface and an unstriped morph. We conducted breeding experiments to determine the mode of inheritance for these 5 dorsal color patterns in E. coqui .W e analyzed results from 14 different cross types, which included 1519 offspring from 71 clutches. We found that color patterns segregate at ratios consistent with a single autosomal locus, 5-allele model, in which all alleles coding for stripes are codominant and the allele coding for the unstriped morph is recessive. We propose that this locus be named ‘‘stripes’’ with alleles B (interocular bar), L (dorsolateral stripes), N (narrow middorsal stripe), W (wide middorsal stripe), and u (unstriped). The results of this experiment suggest the genetic basis of stripe patterns in this well-studied species and provide a model for studying the evolution and maintenance of this phenotypic polymorphism.
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biology and impacts of pacific island invasive species 5 Eleutherodactylus coqui the coqui frog anura leptodactylidae
Pacific Science, 2009Co-Authors: Karen H Beard, Emily A Price, William C PittAbstract:Abstract: The nocturnal, terrestrial frog Eleutherodactylus coqui, known as the coqui, is endemic to Puerto Rico and was accidentally introduced to Hawai‘i via nursery plants in the late 1980s. Over the past two decades E. coqui has spread to the four main Hawaiian Islands, and a major campaign was launched to eliminate and control it. One of the primary reasons this frog has received attention is its loud mating call (85–90 dB at 0.5 m). Many homeowners do not want the frogs on their property, and their presence has influenced housing prices. In addition, E. coqui has indirectly impacted the floriculture industry because customers are reticent to purchase products potentially infested with frogs. Eleutherodactylus coqui attains extremely high densities in Hawai‘i, up to 91,000 frogs ha-1, and can reproduce year-round, once every 1–2 months, and become reproductive around 8–9 months. Although the coqui has been hypothesized to potentially compete with native insectivores, the most obvious potential ecolog...
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population density estimates and growth rates of Eleutherodactylus coqui in hawaii
Journal of Herpetology, 2008Co-Authors: Karen H Beard, Robert Alchokhachy, N C Tuttle, Eric M OneillAbstract:The Puerto Rican terrestrial frog (Eleutherodactylus coqui) has received considerable attention in Hawaii because of its rapid spread, loud mating calls, and its potential threat to native species. Thus far, its invasion potential on the Island of Hawaii remains poorly understood. Critical components for determining this potential are robust estimates of abundance and vital rates across habitat types. To address this lack of information, we used mark-recapture methods to estimate E. coqui survival and abundance, determine growth rates of adult male and female frogs, and relate densities to elevation, snout-vent length (SVL), habitat structure, and invertebrate abundance. Mean adult E. coqui density across eight sites was 62 6 12 adults/100 m 2 and ranged from 6-138 adults/100 m 2 . Our three-year mean adult density estimates were three times greater at three of our study sites (100 adults/100 m 2 ) than the highest long-term estimates from Puerto Rico (33 adults/100 m 2 ). Mean individual growth rates were 0.0078 mm/day (6 0.007 SD, N = 87) for males and 0.0097 mm/day (6 0.009 SD, N = 11) for females. Frogs of similar size were found to be growing slower in Hawaii than Puerto Rico. We found no relationship between elevation and E. coqui density or elevation and SVL or between invertebrate abundance and E. coqui density. However, there was a positive relationship between understory structure and E. coqui density. This relationship suggests that removing understory structure could reduce E. coqui densities, although other potential implications of this management treatment should be considered.
William C Pitt - One of the best experts on this subject based on the ideXlab platform.
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biology and impacts of pacific island invasive species 5 Eleutherodactylus coqui the coqui frog anura leptodactylidae
Pacific Science, 2009Co-Authors: Karen H Beard, Emily A Price, William C PittAbstract:Abstract: The nocturnal, terrestrial frog Eleutherodactylus coqui, known as the coqui, is endemic to Puerto Rico and was accidentally introduced to Hawai‘i via nursery plants in the late 1980s. Over the past two decades E. coqui has spread to the four main Hawaiian Islands, and a major campaign was launched to eliminate and control it. One of the primary reasons this frog has received attention is its loud mating call (85–90 dB at 0.5 m). Many homeowners do not want the frogs on their property, and their presence has influenced housing prices. In addition, E. coqui has indirectly impacted the floriculture industry because customers are reticent to purchase products potentially infested with frogs. Eleutherodactylus coqui attains extremely high densities in Hawai‘i, up to 91,000 frogs ha-1, and can reproduce year-round, once every 1–2 months, and become reproductive around 8–9 months. Although the coqui has been hypothesized to potentially compete with native insectivores, the most obvious potential ecolog...
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An invasive frog, Eleutherodactylus coqui, increases new leaf production and leaf litter decomposition rates through nutrient cycling in Hawaii
Biological Invasions, 2008Co-Authors: Karen H Beard, William C PittAbstract:A frog endemic to Puerto Rico, Eleutherodactylus coqui , invaded Hawaii in the late 1980s, where it can reach densities of 50,000 individuals ha^−1. Effects of this introduced insectivore on invertebrate communities and ecosystem processes, such as nutrient cycling, are largely unknown. In two study sites on the Island of Hawaii, we studied the top-down effects of E. coqui on aerial, herbivorous, and leaf litter invertebrates; herbivory, plant growth, and leaf litter decomposition rates; and leaf litter and throughfall chemistry over 6 months. We found that E. coqui reduced all invertebrate communities at one of the two study sites. Across sites, E. coqui lowered herbivory rates, increased NH _4 ^+ and P concentrations in throughfall, increased Mg, N, P, and K in decomposing leaf litter, increased new leaf production of Psidium cattleianum , and increased leaf litter decomposition rates of Metrosideros polymorpha . In summary, E. coqui effects on invertebrates differed by site, but E. coqui effects on ecosystem processes were similar across sites. Path analyses suggest that E. coqui increased the number of new P. cattleianum leaves and leaf litter decomposition rates of M. polymorpha by making nutrients more available to plants and microbes rather than through changes in the invertebrate community. Results suggest that E. coqui in Hawaii has the potential to reduce endemic invertebrates and increase nutrient cycling rates, which may confer a competitive advantage to invasive plants in an ecosystem where native species have evolved in nutrient-poor conditions.
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isolation of microsatellite loci from the coqui frog Eleutherodactylus coqui
Molecular Ecology Resources, 2008Co-Authors: Maureen B Peters, Karen H Beard, Chris Hagen, Eric M Oneill, Karen E Mock, William C Pitt, Travis C GlennAbstract:Thirteen microsatellite loci were isolated from the coqui frog ( Eleutherodactylus coqui ) and optimized for future research. The loci were screened across 37 individuals from two Puerto Rican populations. Loci were variable with the number of alleles per locus ranging from three to 38. Polymorphic information content ranged from 0.453 to 0.963 and observed heterozygosity for each population ranged from 0.320 to 0.920.
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potential predators of an invasive frog Eleutherodactylus coqui in hawaiian forests
Journal of Tropical Ecology, 2006Co-Authors: Karen H Beard, William C PittAbstract:In Hawaii, where there are no native reptiles or amphibians, 27 species of reptiles and amphibians have established (Kraus 2003); however, few have been studied to determine their ecological impacts. For example, little is known about the impacts of the Puerto Rican frog, Eleutherodactylus coqui Thomas, that recently invaded (late 1980s) (Kraus et al. 1999), and has established on all four main Hawaiian Islands (Kraus & Campbell 2002). However, there are likely to be consequences because E. coqui can attain high densities (20 570 frogs ha-1 on average in Puerto Rico) and consume large quantities of invertebrates (114 000 prey items ha-1 per night on average in Puerto Rico) (Stewart & Woolbright 1996).
Eric M Oneill - One of the best experts on this subject based on the ideXlab platform.
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clinal variation in calls of native and introduced populations of Eleutherodactylus coqui
Copeia, 2011Co-Authors: Eric M Oneill, Karen H BeardAbstract:We determined whether Eleutherodactylus coqui exhibits clinal variation in male advertisement call parameters across its native Puerto Rico and introduced range of Hawaii. In the laboratory, we determined whether clinal variation in call parameters were a result of body size or temperature. Calls correlate with elevation in both Puerto Rico and Hawaii in the following ways: negative for fundamental frequency of each call syllable (Co and Qui), positive with the duration of each call, negative with call rate (calls per minute), and no relationship with call intensity. In the laboratory, we found the negative relationship between elevation and call frequency was best explained by larger body sizes at higher elevations, and that the positive and negative relationships between elevation and call duration, and elevation and call rate, respectively, were best explained by lower temperatures at higher elevations. While frogs in Hawaii exhibited the same relationships between elevation and call parameters found i...
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genetic basis of a color pattern polymorphism in the coqui frog Eleutherodactylus coqui
Journal of Heredity, 2010Co-Authors: Eric M Oneill, Karen H BeardAbstract:Many species of frog exhibit striking color and pattern polymorphisms, but the genetic bases of these traits are not known for most species. The coqui frog, Eleutherodactylus coqui, a species endemic to the island of Puerto Rico, exhibits a wide variety of color and pattern polymorphisms including 4 discrete stripe patterns on its dorsal surface and an unstriped morph. We conducted breeding experiments to determine the mode of inheritance for these 5 dorsal color patterns in E. coqui .W e analyzed results from 14 different cross types, which included 1519 offspring from 71 clutches. We found that color patterns segregate at ratios consistent with a single autosomal locus, 5-allele model, in which all alleles coding for stripes are codominant and the allele coding for the unstriped morph is recessive. We propose that this locus be named ‘‘stripes’’ with alleles B (interocular bar), L (dorsolateral stripes), N (narrow middorsal stripe), W (wide middorsal stripe), and u (unstriped). The results of this experiment suggest the genetic basis of stripe patterns in this well-studied species and provide a model for studying the evolution and maintenance of this phenotypic polymorphism.
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population density estimates and growth rates of Eleutherodactylus coqui in hawaii
Journal of Herpetology, 2008Co-Authors: Karen H Beard, Robert Alchokhachy, N C Tuttle, Eric M OneillAbstract:The Puerto Rican terrestrial frog (Eleutherodactylus coqui) has received considerable attention in Hawaii because of its rapid spread, loud mating calls, and its potential threat to native species. Thus far, its invasion potential on the Island of Hawaii remains poorly understood. Critical components for determining this potential are robust estimates of abundance and vital rates across habitat types. To address this lack of information, we used mark-recapture methods to estimate E. coqui survival and abundance, determine growth rates of adult male and female frogs, and relate densities to elevation, snout-vent length (SVL), habitat structure, and invertebrate abundance. Mean adult E. coqui density across eight sites was 62 6 12 adults/100 m 2 and ranged from 6-138 adults/100 m 2 . Our three-year mean adult density estimates were three times greater at three of our study sites (100 adults/100 m 2 ) than the highest long-term estimates from Puerto Rico (33 adults/100 m 2 ). Mean individual growth rates were 0.0078 mm/day (6 0.007 SD, N = 87) for males and 0.0097 mm/day (6 0.009 SD, N = 11) for females. Frogs of similar size were found to be growing slower in Hawaii than Puerto Rico. We found no relationship between elevation and E. coqui density or elevation and SVL or between invertebrate abundance and E. coqui density. However, there was a positive relationship between understory structure and E. coqui density. This relationship suggests that removing understory structure could reduce E. coqui densities, although other potential implications of this management treatment should be considered.
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isolation of microsatellite loci from the coqui frog Eleutherodactylus coqui
Molecular Ecology Resources, 2008Co-Authors: Maureen B Peters, Karen H Beard, Chris Hagen, Eric M Oneill, Karen E Mock, William C Pitt, Travis C GlennAbstract:Thirteen microsatellite loci were isolated from the coqui frog ( Eleutherodactylus coqui ) and optimized for future research. The loci were screened across 37 individuals from two Puerto Rican populations. Loci were variable with the number of alleles per locus ranging from three to 38. Polymorphic information content ranged from 0.453 to 0.963 and observed heterozygosity for each population ranged from 0.320 to 0.920.
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infection of an invasive frog Eleutherodactylus coqui by the chytrid fungus batrachochytrium dendrobatidis in hawaii
Biological Conservation, 2005Co-Authors: Karen H Beard, Eric M OneillAbstract:The chytrid fungus Batrachochytrium dendrobatidis has contributed to declines and extinctions of amphibians worldwide. B. dendrobatidis is known to infect the frog Eleutherodactylus coqui in its native Puerto Rico. E. coqui was accidentally introduced into Hawaii in the late 1980s, where there are now hundreds of populations. B. dendrobatidis was being considered as a biological control agent for E. coqui because there are no native amphibians in Hawaii. Using a DNA-based assay, we tested 382 E. coqui from Hawaii for B. dendrobatidis and found that 2.4% are already infected. We found infected frogs in four of 10 study sites and on both the islands of Hawaii and Maui. This is the first report of B. dendrobatidis in wild populations in Hawaii. As the range of E. coqui expands, it may become a vector for the transmittance of B. dendrobatidis to geographic areas where B. dendrobatidis does not yet exist.