Red Frog Research Articles

Predator perception of aposematic and cryptic color morphs in two Oophaga species.

Animals that are toxic often advertise their unprofitability to potential predators through bright aposematic colors while cryptic ones blend in with their natural background to avoid predators. In the poison dart frogs, Oophaga pumilio and O. granulifera, some populations in Costa Rica and Panama display cryptic green and aposematic red color morphs. We herein used reflectance spectra from the dorsum of red and green morphs of these frogs to estimate their perception by the visual systems of three potential predators (birds, lizards, and crabs) against three natural backgrounds (leaves, trunks and leaf litter). Statistical analyses revealed no strong differences in color contrast against backgrounds between the two frog species. However, strong effects of frog morph, predator, background, and their interactions were observed. When viewed against diverse backgrounds, red frogs of both Oophaga species are more color conspicuous to birds and Anoline lizards than to crabs. A strong effect of species was observed on luminance contrast. Concerning the latter, green frogs particularly in O. granulifera appear more conspicuous than red frogs, while birds perceive higher brightness contrasts than lizards or crabs. Our results further support the importance of birds and lizards as Oophaga predators and provide a first quantitative comparison of conspicuousness between these two frog species.

Estimates of heterozygosity from single nucleotide polymorphism markers are context-dependent and oftenwrong.

Genetic diversity is frequently described using heterozygosity, particularly in a conservation context. Often, it is estimated using single nucleotide polymorphisms (SNPs); however, it has been shown that heterozygosity values calculated from SNPs can be biased by both study design and filtering parameters. Though solutions have been proposed to address these issues, our own work has found them to be inadequate in some circumstances. Here, we aimed to improve the reliability and comparability of heterozygosity estimates, specifically by investigating how sample size and missing data thresholds influenced the calculation of autosomal heterozygosity (heterozygosity calculated from across the genome, i.e. fixed and variable sites). We also explored how the standard practice of tri- and tetra-allelic site exclusion could bias heterozygosity estimates and influence eventual conclusions relating to genetic diversity. Across three distinct taxa (a frog, Litoria rubella; a tree, Eucalyptus microcarpa; and a grasshopper, Keyacris scurra), we found heterozygosity estimates to be meaningfully affected by sample size and missing data thresholds, partly due to the exclusion of tri- and tetra-allelic sites. These biases were inconsistent both between species and populations, with more diverse populations tending to have their estimates more severely affected, thus having potential to dramatically alter interpretations of genetic diversity. We propose a modified framework for calculating heterozygosity that reduces bias and improves the utility of heterozygosity as a measure of genetic diversity, whilst also highlighting the need for existing population genetic pipelines to be adjusted such that tri- and tetra-allelic sites be included in calculations.

Frog Crabs (Ranina ranina) in South Penghu Marine National Park, Taiwan: A Case Study of Population Dynamics and Recreational Fishing Sustainable Development

The frog crab/red frog crab (Ranina ranina), a species of symbolic significance in the South Penghu Marine National Park, Taiwan, represents a collaboration between marine conservation and recreational fishing under Sustainable Development Goal 14 (SDG14) as defined by the United Nations. From 2020 to 2021, the growth and reproduction of R. ranina were examined in the Taiwan Strait, off the coast of Taiwan. Samples were gathered from the South Penghu Marine National Park water square in Penghu County using red frog crab nets. A comparative analysis of the existing biological literature has revealed that the spawning season of R. ranina differs among populations, as evidenced by varying percentages of ovigerous females: 10–90% in Hachijojima, Japan; 86% in Molokai, Hawaii; 1–17% in the Andaman Sea, Thailand; more than 50% in Mindanao, Philippines; and 30–80% in New South Wales, Australia, and Taiwan. Additionally, analysis of the reproductive patterns, growth parameters, and spawning seasons of R. ranina can serve as a scientific foundation for the implementation of SDG14 as well as the formulation of conservation principles for resource management. This research has underscored the essential role of localized conservation strategies that cohesively resonate with broader global sustainability goals, offering a strategic framework for effective marine resource management.

New Distributional Record of Red Frog Crab, Ranina ranina (Linnaeus, 1758) (Decapoda: Raninidae) with Finding of Maximum Carapace Length from North-West Coast of India

New Distributional Record of Red Frog Crab, Ranina ranina (Linnaeus, 1758) (Decapoda: Raninidae) with Finding of Maximum Carapace Length from North-West Coast of India

Fragments of bombinakinin M exist in lipopolysaccharide-stimulated skin secretions of Bombina maxima and show lipopolysaccharide-neutralizing activity

Lipopolysaccharide (LPS) is a major pathogen-associated pattern molecule that can initiate lethal sepsis. Bioactive peptides in amphibian skin secretions, especially antimicrobial peptides, are essential components of the host immune system and help fight the microbial invasion. In this study, two peptides: peptide 1 (KINRKGPRPPG) and peptide 2 (INRKGPRPPG) were isolated, from skin secretions of the Chinese red belly frog (Bombina maxima). After stimulation with LPS, peptide 1 showed direct LPS-binding activity, low cytotoxicity, immunoregulatory functions in vitro, and neutralizing LPS effects in animal models. Thus, natural peptide 1 exhibits potential as an ideal candidate against LPS.

Morphometric analysis of the red frog crab Curacha Ranina ranina from Balut Island, Sarangani, Davao occidental, Philippines

Morphometric characters relationships of the females and males red frog crab Ranina ranina locally named as “curacha” from Balut Island, Sarangani, Davao Occidental was the main goal in this study. The carapace width (CW), carapace length (CL), abdomen width (AW), abdomen length (AL), propodus length (PL), dactylus length and body weight were assessed. A total of 60 samples were sexed based on the shapes of the abdomens and examined in the laboratory. At the same time, the species body weight was also measured. Most of the females’ R. ranina has body size larger than males. This is due to differences in growth patterns, food availability and size of maturity. In terms of its body weight, females of R. ranina are usually smaller and reaching 400 g in weight while males can reach 900 g in total body weight. It is important to note that males must be large enough to successfully dig female crabs out of the sand to reproduce. The allometric regression found describes changes in soft tissue content (or total animal weight for crustaceans) relative to carapace width/length. This result is consistent with general trends of scaling with body size in animals.

Two new frog species from the Litoria rubella species group from eastern Australia.

The bleating tree frog (Litoria dentata) is one of the more prominent pelodryadid frogs of eastern Australia by virtue of its extremely loud, piercing, male advertisement call. A member of the Litoria rubella species group, L. dentata has a broad latitudinal distribution and is widespread from coastal and subcoastal lowlands through to montane areas. A recent mitochondrial DNA analysis showed a deep phylogeographic break between populations of L. dentata on the mid-north coast of New South Wales. Here we extended the mitochondrial survey with more geographically comprehensive sampling and tested the systematic implications of our findings with nuclear genome wide single-nucleotide polymorphism, morphological and male advertisement call datasets. While similar in appearance and in male advertisement call, our integrative analysis demonstrates the presence of three species which replace each other in a north-south series. We redescribe Litoria dentata, which is restricted to coastal north-eastern New South Wales, and formally describe Litoria balatus sp. nov., from south-eastern Queensland, and Litoria quiritatus sp. nov., from the mid-coast of New South Wales to north-eastern Victoria.

Virtual screening and rational design of antioxidant peptides based on tryptophyllin L structures isolated from the Litoria rubella frog.

Discovery of natural antioxidants has been carried out for decades relying mainly on experimental approaches that are commonly associated with time and cost demanding biochemical assays. The maturation of quantitative structure activity relationship (QSAR) modelling has provided an alternative approach for searching and designing antioxidant compounds with alleviated costs. As a contribution to this approach, this work aimed to establish a fragment-based 3D-QSAR procedure to discover and design potential antioxidants based on tryptophyllin L structures isolated from the red tree frog Litoria rubella. A force field and a Gaussian 3D-QSAR model were built to screen for potential antioxidants from tripeptide fragments covering all sequences of tryptophyllin L database. Among those, PWY(NH2 ) corresponding tryptophyllin L 4.1 was predicted to have the highest 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) radical cation (ABTS+ ·) scavenging capability. Two newly designed peptides PYW and PYW(NH2 ) together with PWY(NH2 ), tryptophyllin L 4.1, and the reference peptide PWY were synthesized and subjected to two antioxidant assays including ABTS scavenging and ferric reducing antioxidant power assays. Although the experimental TEAC values of the five peptides were roughly similar to those from predictions, the activity order was not in agreement with the predictions. The dissimilarities were accounted by the difference in the experimental procedures, the deviation of modelling regression, and the synergetic effect of structural and experimental features. The ABTS radical scavenging assays revealed that all the tested peptides were strong ABTS+ · scavengers with the antioxidant capabilities approximately twice as high as trolox and higher than glutathione. The ferric reducing activities of the peptides were, on the other hand, much weaker than that of trolox suggesting different antioxidant mechanisms inserted by trolox and the peptides. This work was a demonstration that 3D-QSAR methods can be employed in conjunction with experimental methods to effectively detect and design antioxidant peptides.

Death-feigning in a Red Narrow-mouthed Frog, Microhyla rubra (Boulenger 1882), in India

Death-feigning in a Red Narrow-mouthed Frog, Microhyla rubra (Boulenger 1882), in India

The index of ideality of correlation improves the predictive potential of models of the antioxidant activity of tripeptides from frog skin (Litoria rubella)

It is usually held that good-quality models for the biological activity of peptides must take into account their 3D architecture and descriptors of quantum mechanics. However, the present study shows that it is possible to build up models without these complex calculations. The structure of tripeptides represented by sequences of one-symbol abbreviations of the corresponding amino acids serves to build up quantitative structure-activity relationships for the antioxidant activity of tripeptides from frog skin. The statistical quality of the best model for the validation set is n = 27, r2 = 0.93, RMSE = 0.15.

Antioxidant activities of major tryptophyllin L peptides: A joint investigation of Gaussian-based 3D-QSAR and radical scavenging experiments.

The red tree frog Litoria rubella from Australia has been studied for several decades showing that their dorsal skin glands secrete a number of small peptides containing a Pro-Trp sequence, known as tryptophyllin L peptides. Although peptides from many genera of Australian frogs have been reported to possess a variety of biological activities, the bioactivities of this peptide family have remained to be discovered. In this study, we investigated the antioxidant potency of a number of tryptophyllin L peptides for the first time using a joint statistical and experimental approach in which predictions based on Gaussian three-dimensional quantitative structure-activity relationship (3D-QSAR) models were employed to guide an in vitro experimental investigation. Two tryptophyllin tripeptides P-W-L (OH) and P-W-L (NH2 ) were predicted to have the Trolox equivalent antioxidant capacity (TEAC) values of 0.80 and 0.87 μM Trolox/μM peptide, respectively. With those promising results, antioxidant capabilities of five tryptophyllin L peptides with the common core Pro-Trp-Leu were synthesized and subjected to 1,1-diphenyl-2-picrylhydrazyl (DPPH), ferric reducing ability of plasma (FRAP) and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) radical cation (ABTS˙+ ) radical scavenging assays. The tests indicated that all the tested tryptophyllin L peptides, noticeably S-P-W-L (OH) and F-P-W-L (NH2 ), are strong ABTS˙+ radical scavengers and moderate scavengers in the other two assays. The results, thus, suggested that the tryptophyllin L peptides are likely to be a part of the skin antioxidant system helping the frog to cope with drastic change in oxygen exposure and humidity, as they inhabit over a large area of Australia with a wide climate variation.

Red hot frogs: identifying the Australian frogs most at risk of extinction

More than a third of the world’s amphibian species are listed as Threatened or Extinct, with a recent assessment identifying 45 Australian frogs (18.4% of the currently recognised species) as ‘Threatened’ based on IUCN criteria. We applied structured expert elicitation to 26 frogs assessed as Critically Endangered and Endangered to estimate their probability of extinction by 2040. We also investigated whether participant experience (measured as a self-assigned categorical score, i.e. ‘expert’ or ‘non-expert’) influenced the estimates. Collation and analysis of participant opinion indicated that eight species are at high risk (>50% chance) of becoming extinct by 2040, with the disease chytridiomycosis identified as the primary threat. A further five species are at moderate–high risk (30–50% chance), primarily due to climate change. Fourteen of the 26 frog species are endemic to Queensland, with many species restricted to small geographic ranges that are susceptible to stochastic events (e.g. a severe heatwave or a large bushfire). Experts were more likely to rate extinction probability higher for poorly known species (those with <10 experts), while non-experts were more likely to rate extinction probability higher for better-known species. However, scores converged following discussion, indicating that there was greater consensus in the estimates of extinction probability. Increased resourcing and management intervention are urgently needed to avert future extinctions of Australia’s frogs. Key priorities include developing and supporting captive management and establishing or extending in-situ population refuges to alleviate the impacts of disease and climate change.

A ketocarotenoid-based colour polymorphism in the Sira poison frog Ranitomeya sirensis indicates novel gene interactions underlying aposematic signal variation.

The accumulation of red ketocarotenoids is an important component of coloration in many organisms, but the underlying mechanisms are poorly understood. In some organisms, ketocarotenoids are sequestered from the diet and can accumulate when enzymes responsible for carotenoid breakdown are disrupted. In other organisms, ketocarotenoids are formed endogenously from dietary precursors via oxidation reactions carried out by carotenoid ketolase enzymes. Here, we study the genetic basis of carotenoid coloration in an amphibian. We demonstrate that a red/yellow polymorphism in the dendrobatid poison frog Ranitomeya sirensis is due to the presence/absence of ketocarotenoids. Using whole-transcriptome sequencing of skins and livers, we found that a transcript encoding a cytochrome P450 enzyme (CYP3A80) is expressed 3.4-fold higher in livers of red frogs versus yellow. As CYP3A enzymes are known carotenoid ketolases in other organisms, our results point to CYP3A80 as a strong candidate for a carotenoid ketolase in amphibians. Furthermore, in red frogs, the transcript encoding the carotenoid cleavage enzyme BCO2 is expressed at a low level or as a splice variant lacking key catalytic amino acids. This suggests that BCO2 function may be disrupted in red frogs, providing a mechanism whereby the accumulation of ketocarotenoids and their dietary precursors may be enhanced.

Being red, blue and green: the genetic basis of coloration differences in the strawberry poison frog (Oophaga pumilio)

BackgroundAnimal coloration is usually an adaptive attribute, under strong local selection pressures and often diversified among species or populations. The strawberry poison frog (Oophaga pumilio) shows an impressive array of color morphs across its distribution in Central America. Here we quantify gene expression and genetic variation to identify candidate genes involved in generating divergence in coloration between populations of red, green and blue O. pumilio from the Bocas del Toro archipelago in Panama.ResultsWe generated a high quality non-redundant reference transcriptome by mapping the products of genome-guided and de novo transcriptome assemblies onto a re-scaffolded draft genome of O. pumilio. We then measured gene expression in individuals of the three color phenotypes and identified color-associated candidate genes by comparing differential expression results against a list of a priori gene sets for five different functional categories of coloration – pteridine synthesis, carotenoid synthesis, melanin synthesis, iridophore pathways (structural coloration), and chromatophore development. We found 68 candidate coloration loci with significant expression differences among the color phenotypes. Notable upregulated examples include pteridine synthesis genes spr, xdh and pts (in red and green frogs); carotenoid metabolism genes bco2 (in blue frogs), scarb1 (in red frogs), and guanine metabolism gene psat1 (in blue frogs). We detected significantly higher expression of the pteridine synthesis gene set in red and green frogs versus blue frogs. In addition to gene expression differences, we identified 370 outlier SNPs on 162 annotated genes showing signatures of diversifying selection, including eight pigmentation-associated genes.ConclusionsGene expression in the skin of the three populations of frogs with differing coloration is highly divergent. The strong signal of differential expression in pteridine genes is consistent with a major role of these genes in generating the coloration differences among the three morphs. However, the finding of differentially expressed genes across pathways and functional categories suggests that multiple mechanisms are responsible for the coloration differences, likely involving both pigmentary and structural coloration. In addition to regulatory differences, we found potential evidence of differential selection acting at the protein sequence level in several color-associated loci, which could contribute to the color polymorphism.

Continental-scale citizen science data reveal no changes in acoustic responses of a widespread tree frog to an urbanisation gradient

AbstractOne of the major drivers of global biodiversity declines is habitat loss and modification, often associated with anthropogenic environments. To mitigate biodiversity declines, a comprehensive understanding of how species respond to novel anthropogenic environments is required. Compared to natural habitats, human-modified environments often have increased noise and light pollution, potentially affecting acoustically communicating species, such as frogs. These areas may force animals to modulate or alter their calls to communicate with potential mates, as they compete with anthropogenic noise. Using large-scale citizen science data, coupled with remotely sensed data, we examined how the advertisement calls of the Australian red tree frog (Litoria rubella) varied in response to a gradient consistent with anthropogenic disturbance. After measuring a suite of acoustic properties of L.rubella across its range, we discovered that their advertisement calls showed no response to a disturbance urbanisation gradient. The advertisement calls of the species were highly variable, both at continental and local scales. Our results indicate that acoustic communication in male L.rubella may not be impeded in human-modified habitats as (1) they are a loud species typically heard over background noise and multi-species choruses and (2) their calls are highly variable—potentially serving as a buffer to any acoustic disturbances. Overall, our results provide evidence that some frog species may be acoustically urban tolerant and provide a greater understanding of the responses frogs exhibit to human-mediated environmental change.

Diversity of fauna as one of indicator of forest management in Tahura Wan Abdul Rachman

Taman Hutan Raya Wan Abdul Rachman (Tahura WAR) is located at Lampung Province, Indonesia. University of Lampung as the state university has mandatory around 1.134 hectare to manage from Tahura WAR as Forest Education. Research has been done in this area. The purpose of the research is identifying biodiversity of fauna in Forest Education of University of Lampung at Tahura WAR. The research has been done from March to May 2018 (dry season) and October to December 2018 (rainy season). Each month collected data was consisted of six days observation. The method of the research is using traps, it is to lay the traps on the surface of soil by plastic bucket, with 72 traps at different location that separated by study site. The research result were found big black ants, small black ants, mosquitoes, millipedes, crickets, spiders, termites, snails, glomerides, small red ants, big red ants, frogs, small scorpion, caterpillar and dung beetle. Diversity Index of Shannon Wienner classified Tahura WAR as moderate which indicate the forest has good maintain as the aspect of ecology and the aspect of sustained of forest.

New archaeological insights from petrographic analysis of ceramics from the Bocas del Toro Archipelago, Panama

In this study, we conducted the first petrographic analysis of pottery from several Pre-Columbian archaeological sites located in Bocas del Toro province along the Caribbean coast of Panama. The fifty-four sherds examined in this study included surface finds collected from the sites of Red Frog (RF) and Punta Vieja Arriba (PVA) on Bastimentos Island, the Cerro Brujo (CB) site on the mainland, and excavated samples from Sitio Drago (SD), Isla Colon. Petrographic examination of sherd thin sections shows that different sandy materials (seven constituent natural and/or manually-added temper groups) were used in their production. Representative sherd compositions from each group were determined by petrographic point-counts (n=200) using two matrix (silt and clay) and 14 mineral and rock fragment categories for sand grains. The sand in RF sherds is mainly fragments of mudstone, whereas sherds from the PVA and CB sites contain different proportions of sand-sized quartz, feldspar, dense minerals, and several varieties of volcanic lithic fragments. The latter components are constituents derived from local Panamanian geologic units, including one with pyroclastic temper that likely comes from a volcanically active region, such as the El Baru Volcano. Some of the archaeological sites (SD and PVA) have a greater variety of sherd compositional/temper groups than others, implying that people inhabiting these sites were actively engaged in acquiring materials and/or ceramics from multiple sources regionally.

Dunphy Lake in Warrumbungle National Park, NSW: aquatic animal community after the Wambelong fire in 2013

ABSTRACT Fires are a common occurrence in Australian terrestrial ecosystems. A large fire occurred in January 2013 within and adjacent to the Warrumbungle National Park, near Coonabarabran in NSW, burning over 560 km2 of the park and surrounding region (the Wambelong fire). The Wambelong fire affected Dunphy Lake, the only lake in the park. In this study, we assessed the post-fire aquatic animal community of the lake in March and September 2014. At the times of sampling the lake was largely dry and had only small isolated pools. We found 53 invertebrate taxa including the larvae of the dragonfly Austrogynacantha heterogena and one vertebrate species (larvae of the frog Litoria rubella) in the pool-water samples. Artificial inundation of the lake sediment samples under laboratory conditions led to the emergence of 31 taxa, totalling 62 taxa in the lake overall. Most taxa found in the lake are opportunistic and characteristic of those in still-water bodies. Dunphy Lake seems to be highly resilient in sustai...

Food as Outreach: Bridging Social Boundaries with Sacred Feasts

Food is a medium for extending charity and constituting community, in the face of social and cultural divisions, based on perceptions of purity. The work of charitable groups The Red Frogs, The Homeless Run, and Reverend Bill Crews’ Loaves and Fishes in contemporary Australia creates links between cultural and spiritual food practices of religious and secular groups. Food charity transcends boundaries embracing the marginalised and needy groups of society, building temporary and permanent nourishing communities, while rejecting tensions of purity-based social division. This is the ?rst academic treatment of all three charities, which have to date been featured only in the popular media. 
 Food charity extends commensality to those who are frequently separated from the charity providers. This feeds physical and spiritual needs of both benefactors and bene?ciaries. The benefactors accrue a sense of personal success in living out their faith and the needy experience purposefully given commensality and acceptance. Such charitable actions challenge the notions of purity that divide people, demonstrate the importance of practical faith, and utilise the power of food regularly to build temporary and permanent communities based on care and commensality. They work to protect, nourish, enrich, and elevate the lives of those who bene?t from the food distributed, rejecting social division on the basis of socially constructed understandings of purity.

Red frogs are more devilish than their green counterparts

Red frogs are more devilish than their green counterparts