Poison Frog Research Articles

Infanticide is driven by unfamiliarity with offspring location and associated with androgenic shifts in mimic poison frogs

Infanticide is widespread across the animal kingdom, but the physiological drivers of infanticide versus care or neglect are relatively unexplored. Here, we identified salient environmental and physiological antecedents of infanticide in the mimic poison frog (Ranitomeya imitator), a biparental amphibian in which female parents feed their tadpoles unfertilized eggs. Specifically, we explored potential environmental cues influencing infant-directed behavior by evaluating changes in the frequency of food provisioning and tadpole mortality after either cross-fostering tadpoles between family units or displacing tadpoles within the terraria of their parents. We found that changes in offspring location reduce care and increase infanticide. Specifically, parents fed their displaced offspring less and, in some instances, tadpole mortality increased. We also investigated whether care and infanticide were related to changes in steroid hormone concentrations in an unfamiliar setting. Infanticide of fertilized eggs and hatchlings in the new territory included cannibalism and was associated with lower testosterone concentrations, but not with changes in corticosterone. Overall, our results support earlier findings that familiarity with offspring location drives parental investment in poison frogs, while indicating an association between low androgen levels and infanticidal behavior in an amphibian.

Infanticide is driven by unfamiliarity with offspring location and associated with androgenic shifts in mimic poison frogs.

Offspring location drives parental decisions of care vs. infanticide.In novel territories, adults cannibalize conspecific, unrelated young.Lower circulating testosterone in novel territory is associated with infanticide.

Expression and degradation function analysis of the key genes from Arthrobacter nitroquajacolicus HW08 in Lactococcus lactis for the degradation of swainsonine

In order to mitigate the adverse effects of madrassa poisoning disease on our livestock industry and to fully utilize the potential pasture resources, biodegradation of locoweed can remove swainsonine, the major toxic component of locoweed, so that the locoweed can be used as high-quality forage. Arthrobacter nitroquajacolicus HW08 can stably and efficiently degrade swainsonine. In this study, Lactococcus lactis, as a food-grade microorganism, was used as a vector to express four key degradation genes from A. nitroquajacolicus HW08. Subsequently, liquid chromatography was employed to evaluate the swainsonine-degrading performance. The crude enzyme solution extracted from the L. lactis strain transformed with the ethanol dehydrogenase gene A1R6C3 degraded 323.4 μg of swainsonine in 24 h at 30 ℃. The crude enzyme solutions from the L. lactis strains transformed with the genes encoding glutathione synthase, esterase/acyl hydrolase, and glycosyltransferase did not show any degradation ability for swainsonine when being used alone but degraded about 140.5 μg of swainsonine when being used in mixture. The findings will help the clinical promotion of swainsonine-degrading engineering strains and provide new research ideas for the prevention and treatment of swainsonine poisoning in animals and the detoxification and utilization of locoweed.

Geographical distribution of caudatoside and ptaquiloside in bracken ferns in Northern Europe

Bracken ferns (genus Pteridium) are among the most prevalent plants worldwide, with their distribution expanding due to their invasive nature. The environmental implications of their proliferation in areas affected by human activity, natural disasters, or land-use changes are concerning, primarily because of the carcinogenic illudane glycosides they produce. These compounds cause domestic and wildlife animal poisoning, as well as contamination of dairy products and drinking water. Several illudane glycosides are known, but usually only ptaquiloside (PTA) is monitored. This study investigates the spatial and temporal variations in illudane glycosides PTA, caudatoside (CAU) and ptesculentoside (PTE) across two phenotypes of Pteridium aquilinum (vars. aquilinum and latiusculum) over a broad geographic range spanning Denmark, Sweden, and Finland, encompassing 66 locations. We analysed different parts of the fern fronds (the tips and the lowest pinnae) using LC–MS and statistically explored the influence of phenotype, frond part, geographic location, sunlight exposure, and the surrounding ecosystem on glycoside content. Our findings reveal that PTA accounts for approximately two-thirds of the total illudane glycoside content, followed by CAU at nearly one-third, and a minor contribution from PTE. Glycoside levels were not influenced by phenotypic varieties or the studied environmental factors, but were significantly affected by geographic location. Specifically, CAU levels increased progressively towards the northeast, while PTA concentrations were highest in Denmark and markedly decreased in northeastern countries by over threefold, presumably due to climatic gradient. It has been further supported by temporal analysis in selected PTA-dominant regions indicating a reduction in PTA towards the end of the growing season, aligning its levels with those of CAU. Our study highlights that CAU concentrations in bracken ferns may equal or surpass PTA, contesting the prevailing view that PTA is the only notable illudane glycoside in Bracken. To provide unbiased assessment of the potential risks posed by P. aquilinum in the region, environmental and toxicological research should include measurements of not only PTA, but also CAU and, if possible, PTE.

Developments in the study of poison frog evolutionary ecology II: decoding hidden messages in their coloration and unique behaviours

Developments in the study of poison frog evolutionary ecology II: decoding hidden messages in their coloration and unique behaviours

Effects of parental care on skin microbial community composition in poison frogs.

Parent-offspring interactions constitute the first contact of many newborns with their environment, priming community assembly of microbes through priority effects. Early exposure to microbes can have lasting influences on the assembly and functionality of the host's microbiota, leaving a life-long imprint on host health and disease. Studies of the role played by parental care in microbial acquisition have primarily focused on humans and hosts with agricultural relevance. Anuran vertebrates offer the opportunity to examine microbial community composition across life stages as a function of parental investment. In this study, we investigate vertical transmission of microbiota during parental care in a poison frog (Family Dendrobatidae), where fathers transport their offspring piggyback-style from terrestrial clutches to aquatic nurseries. We found that substantial bacterial colonization of the embryo begins after hatching from the vitelline envelope, emphasizing its potential role as microbial barrier during early development. Using a laboratory cross-foster experiment, we demonstrated that poison frogs performing tadpole transport serve as a source of skin microbes for tadpoles on their back. To study how transport impacts the microbial skin communities of tadpoles in an ecologically relevant setting, we sampled frogs and tadpoles of sympatric species that do or do not exhibit tadpole transport in their natural habitat. We found more diverse microbial communities associated with tadpoles of transporting species compared to a non-transporting frog. However, we detected no difference in the degree of similarity between adult and tadpole skin microbiotas, based on whether the frog species exhibits transporting behavior or not. Using a field experiment, we confirmed that tadpole transport can result in the persistent colonization of tadpoles by isolated microbial taxa associated with the caregiver's skin, albeit often at low prevalence. This is the first study to describe vertical transmission of skin microbes in anuran amphibians, showing that offspring transport may serve as a mechanism for transmission of parental skin microbes. Overall, these findings provide a foundation for further research on how vertical transmission in this order impacts host-associated microbiota and physiology.

Epidemiological characteristics and toxicant type of acute poisoning cases in China, 2016-2022

Objective: To analyze the acute poison epidemic and provide evidence for developing prevention and control strategies for acute poisoning. Methods: A retrospective analysis was conducted on acute poisoning cases collected from 2016 to 2022 in a health emergency information platform for acute poisoning accidents. The cases were grouped according to the distribution of poisoning occurrence time, geographic distribution, demographic distribution, types of toxicants, poisoning causes, and outcomes. Data were organized and analyzed using Excel 2016 and R 4.2.3. Results: A total of 95 754 acute poisoning cases were included in this study. The primary toxicants were pesticides, drugs, and industrial/household chemicals, accounting for 30.4%, 22.4%, and 20.4% of the total cases, respectively. Acute poisoning occurred throughout the year, with the highest frequency from June to August, accounting for 31.9%. The seasonal distribution varied among different types of toxicants. Except for plant poisoning, which showed a bimodal distribution, the other poisonings showed an unimodal distribution. There was a strong seasonality in fungal poisoning, which peaked in July. There was an obvious seasonality in animal poisoning, with a peak in August. The proportion of biological poisonings in the southwest region was higher than in other regions, including plants, animals, and fungi. There were more females than males, and their education level was mainly junior high school and below (35.2%). The main occupation was farmers (34.2%), and the main causes of poisoning were accidents and suicides. The case fatality rate of all poisoning cases was 1.24%. Pesticide poisoning was the most common type, and chlorfenapyr (11.68%), Diquat (7.23%), and paraquat (7.05%) ranked as the top three toxicants. Conclusions: The occurrence of acute poisoning has an obvious seasonal trend, and the toxicant spectrum of different regions and populations is different. A comprehensive poisoning surveillance system can provide a better understanding of the occurrence of poisonings, and facilitate the formulation of more scientifically precise poisoning prevention and control strategies.

Detectability of a poison frog and its Batesian mimic depends on body posture and viewing angle.

Aposematic signals warn predators that prey should be avoided due to dangerous secondary defences. However, as warning signals do not always produce avoidance, warning colors may evolve as a trade-off balancing detectability against signal saliency. For Batesian mimics, which display salient signals but lack secondary defenses, the costs of predator encounters are greater, potentially increasing the benefit of crypsis. This raises the question of whether imperfect mimicry may reduce detectability while retaining mimetic efficacy. We tested this hypothesis with the poisonous frog Ameerega bilinguis and undefended Batesian mimic Allobates zaparo, using computational visual modeling and screen-based detection trials with human participants. We found that both species incorporate camouflage into their warning colors, but to different degrees depending on viewing angle and behavior. Contrary to expectation, we found differences in detectability between model and mimic that do not adhere to the hypothesized cryptic mimetic phenotype. To aerial observers, we found the mimic to be more detectable than the model. To terrestrial observers, likely owing to the model's bright ventral color, we found the model more detectable in viewing angles that highlight the ventral coloration, whereas the mimic was more detectable in viewing angles that highlight the dorsal coloration. Consequently, we suggest that in addition to being the result of perceptual or developmental constraints, imperfect mimicry may also evolve as an adaptive strategy which balances camouflage with different signaling functions. Our findings complement the emerging view that aposematic signals may evolve in response to a multitude of selection pressures beyond aversion alone.

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.

Molecular phylogenetics uncovers two new species in the genus Phyllobates (Anura, Dendrobatidae): the terrible frog gets two new sisters.

True poison-dart frogs (Phyllobates, Dendrobatidae) evolved the ability to secrete batrachotoxins, the most powerful alkaloids known to date. The genus comprises five species whose systematics, at first glance, appeared clear. The most derived clade would include two Colombian species (P.terribilis and P.bicolor) with the highest toxicity, the largest body size, and predominantly yellow body colouration. The other three species (P.aurotaenia, P.vittatus, and P.lugubris) are less toxic on average, have smaller size, and are predominantly black with bright dorsolateral stripes. Recent research has revealed the existence of two major lineages among the three Colombian species. The northern lineage appears to result from a complex evolutionary history, including perhaps introgression among yellow and black taxa. The southern lineage instead revealed the existence of new clades closely related to P.terribilis, black and yellow, that arguably deserve their recognition as new species. Here, available evidence is combined to support the erection of southern populations of P.aurotaenia as a new highly toxic species, sister to P.terribilis, and much closer to it than to any other yellow or black-bodied species, Phyllobatessamperi sp. nov. Their common ancestor is sister to an additional yellow species, which we also describe here as Phyllobatesbezosi sp. nov. Both new species can be externally diagnosed using colouration. Our previous and current analyses also suggest the existence of additional taxa and corroborate multiple transitions in colouration across these hypertoxic taxa.

Novel and classical methods similarly describe variation in territory size among males in Neotropical poison frogs with contrasting reproductive and behavioral strategies

Territoriality is a form of social dominance concerning the use of space that ensures the territory owner primary access to critical resources. The territory is defended with visual displays, advertisement calls, physical attacks, or chemical signals. The territory is frequently estimated by mapping locations where an animal is observed engaging in territorial behavior or by tracking. However, these approaches may over- or underestimate the areas defended. Thus, the use of approaches explicitly determining defended areas is critical to properly characterize the territory. Intrusion experiments can elicit a response in territory holders, allowing one to characterize their aggressive responses; however, the aggressive response depends on the species. We describe an approach to experimentally estimate the territory size using playback experiments in a species that exhibits a stereotypical phonotactic response: the nurse frog, Allobates aff. trilineatus and develop a new behavioral index that allows assessing territory size in response to playbacks for a species with non-stereotyped phonotactic response: the endangered Lehmann’s poison frog, Oophaga lehmanni. We conducted 772 playback experiments on 18 males of A. aff. trilineatus, and 222 on nine males of O. lehmanni. We analyzed the results of playback experiments with three different area estimators regularly used to estimate space use and evaluated whether these estimates are correlated. The shape and size of territories varied among individuals and estimators in both species. Although we found that the absolute size of the territory depends on the method used, estimates were strongly correlated, meaning that different estimators similarly describe variation in territory size among males. Choosing an analysis method may not be particularly important for studying the characteristics of territoriality over space and time but using a systematic and standardized experimental approach that also incorporates the particularities of the aggressive response of each species is essential to understand the evolution of space use by poison frogs and other territorial species.

Activity of forkhead box P2-positive neurons is associated with tadpole begging behaviour.

Motor function is a critical aspect of social behaviour in a wide range of taxa. The transcription factor forkhead box P2 (FoxP2) is well studied in the context of vocal communication in humans, mice and songbirds, but its role in regulating social behaviour in other vertebrate taxa is unclear. We examined the distribution and activity of FoxP2-positive neurons in tadpoles of the mimic poison frog (Ranitomeya imitator). In this species, tadpoles are reared in isolated plant nurseries and are aggressive to other tadpoles. Mothers provide unfertilized egg meals to tadpoles that perform a begging display by vigorously vibrating back and forth. We found that FoxP2 is widely distributed in the tadpole brain and parallels the brain distribution in mammals, birds and fishes. We then tested the hypothesis that FoxP2-positive neurons would have differential activity levels in begging or aggression contexts compared to non-social controls. We found that FoxP2-positive neurons showed increased activation in the striatum and cerebellum during begging and in the nucleus accumbens during aggression. Overall, these findings lay a foundation for testing the hypothesis that FoxP2 has a generalizable role in social behaviour beyond vocal communication across terrestrial vertebrates.

Development of a gas chromatography-mass spectrometric technique for the biological control of volatile industrial pollutants

Introduction. General industrial pollutants, which includes volatile industrial pollutants (VIP) allyl chloride, butyl chloride, chloroacetonitrile, pentachloroethane, hexachloroethane, trans-1,4-dichloro-2-butene, acrylonitrile, methacrylonitrile, methyl methacrylate, ethyl methacrylate, methyl acrylate, 2-nitropropane, nitrobenzene , diethyl ether, tetrahydrofuran and carbon disulfide are widely used in the domestic chemical industry, but effective methods for the quantitative determination of their biomarkers in the biological media of chemical production workers have not yet been developed. The purpose of the study is to develop a highly sensitive gas chromatographic technique for the determination of compounds of the VIP group in whole blood and urine for their biological control, and its testing using modeling of intoxication in laboratory animals. Material and methods. Experimental modeling of intoxication was carried out with subcutaneous (s/c) injection of toxicants to male chinchilla rabbits. Determination of biomarkers of toxicants was performed using a gas chromatograph with a single quadrupole mass analyzer (GC-MS) with preliminary extraction of components from the vapor phase above the sample by solid-phase microextraction. Results. A method for the determination of allyl chloride, butyl chloride, chloroacetonitrile, pentachloroethane, hexachloroethane, trans-1,4-dichloro-2-butene, acrylonitrile, methacrylonitrile, methyl methacrylate, ethyl methacrylate, methyl acrylate, 2-nitropropane, nitrobenzene, diethyl ether, tetrahydrofuran, and carbon disulfide in blood and urine was developed and metrologically certified. The achieved limits of quantification are no more than 1 ng/ml with a detection limit of 0.2 ng/ml in blood and urine. Limitations. Toxicokinetic parameters were experimentally determined on one animal species; allometric scaling was used for extrapolation to humans. Conclusion. Analysis of the results of the assessment of the expected concentrations of VIP in blood and urine shows that biological control in the working area at the level of 0.5 MPC can be carried out for carbon disulfide, diethyl ether, butyl chloride, 1,4-dichlorobutene-2 and tetrahydrofuran in the study of blood and urine; methacrylonitrile and hexachloroethane (the lower value of the determination limit) – in the study of urine only. The developed approaches to substantiate methods of biological control of harmful substances are a scientific and methodological platform for the introduction of biological MPC and ensuring the chemical safety of the Russian Federation.

Activity of FoxP2-positive neurons is associated with tadpole begging behavior.

Motor function is a critical aspect of social behavior in a wide range of taxa. The transcription factor FoxP2 is well studied in the context of vocal communication in humans, mice, and songbirds, but its role in regulating social behavior in other vertebrate taxa is unclear. We examined the distribution and activity of FoxP2-positive neurons in tadpoles of the mimic poison frog (Ranitomeya imitator). In this species, tadpoles are reared in isolated plant nurseries and are aggressive to other tadpoles. Mothers provide unfertilized egg meals to tadpoles that perform a begging display by vigorously vibrating back and forth. We found that FoxP2 is widely distributed in the tadpole brain and parallels the brain distribution in mammals, birds, and fishes. We then tested the hypothesis that FoxP2-positive neurons would have differential activity levels in begging or aggression contexts compared to non-social controls. We found that FoxP2-positive neurons showed increased activation in the striatum and cerebellum during begging and in the nucleus accumbens during aggression. Overall, these findings lay a foundation for testing the hypothesis that FoxP2 has a generalizable role in social behavior beyond vocal communication across terrestrial vertebrates.

Fighters and friends: female dominance hierarchy and male territoriality in a multicoloured poisonous frog

Fighters and friends: female dominance hierarchy and male territoriality in a multicoloured poisonous frog

The importance of reproductive isolation in driving diversification and speciation within Peruvian mimetic poison frogs (Dendrobatidae)

To explain how populations with distinct warning signals coexist in close parapatry, we experimentally assessed intrinsic mechanisms acting as reproductive barriers within three poison-frog species from the Peruvian Amazon belonging to a Müllerian mimetic ring (Ranitomeya variabilis, Ranitomeya imitator and Ranitomeya fantastica). We tested the role of prezygotic and postzygotic isolation barriers between phenotypically different ecotypes of each species, using no-choice mating experiments and offspring survival analysis. Our results show that prezygotic mating preference did not occur except for one specific ecotype of R. imitator, and that all three species were able to produce viable inter-population F1 hybrids. However, while R. variabilis and R. imitator hybrids were able to produce viable F2 generations, we found that for R. fantastica, every F1 hybrid males were sterile while females remained fertile. This unexpected result, echoing with Haldane’s rule of speciation, validated phylogenetic studies which tentatively diagnose these populations of R. fantastica as two different species. Our work suggests that postzygotic genetic barriers likely participate in the extraordinary phenotypic diversity observed within Müllerian mimetic Ranitomeya populations, by maintaining species boundaries.

The Determination of the Prohibited Herbicide 4,6-Dinitro-Ortho-Cresol (DNOC) in Poisoned Domestic and Wild Animals in Italy.

This study reports the determination of DNOC in the baits and gastric contents of poisoned dogs and wild canids collected in the Abruzzo region between 2014 and 2022. A total of 663 samples of the baits and carcasses of domestic and wild animals were analyzed for the determination of DNOC through GC-MS. DNOC was found to be present in 58 cases from 663 analyzed samples, with 49 poison baits and nine gastric content samples from dogs and red foxes. This study confirms for the first time that the banned pesticide DNOC still poisons both domestic and wild animals in the Abruzzo region. It should be considered that this study was carried out on a population of animals from a regional geographical area, and more detailed country-wide studies need to be carried out to obtain the incidence of poisoning from this herbicide in Italy. Furthermore, these findings emphasize the importance of considering this chemical in differential diagnosis during toxicological investigations of animal poisoning.

Intoxicações de animais por praguicidas da classe dos carbamatos

Intentional poisoning by exogenous agents occurs with certain frequency and represents a high percentage of the causes of death in small animals in Veterinary Medicine. The carbamate popularly known in Brazil as “chumbinho”, is often linked to cases of criminal poisoning of domestic animals in the country, being sold illegally and widely used as a domestic rodenticide. The objective of this work was to discuss some types of pesticides and their toxicities, having inorganic and organic substances in their composition. A systematic review of national and international literature was carried out using the following key words: anticholinesterases, carbamates, pesticides, poisoning; using the following scientific databases for academic research: Virtual Health Library (VHL), SciELO, Scopus, CAPES Journal Portal, Google Scholar, PubMed and Biomed Central. Pesticides, with their inorganic chemical nature, appear in everyday life and are classified as organochlorines, organophosphates, carbamates and others, having an immediate effect in the organism. Cases of poisoning involving toxic agents illegally sold as rodenticides are very frequent and it is noted that, in most cases, the lack of knowledge and/or lack of information on the part of owners regarding the subject are significant factors in cases of sudden death of poisoned animals treated in veterinary clinics. The best way to reduce the incidence of poisoning in companion animals can be through training veterinarians working in the area of first aid, as well as their involvement in prevention through raising awareness among the population regarding the use of these toxic agents. There is also a need for greater supervision of the illegal marketing of these chemicals by public bodies.

USO IRRACIONAL DOS MEDICAMENTOS EM CÃES E GATOS

The irrational use of medicines is directly related to the establishment of the need to use the medication. Due to the growth of pharmaceutical industry, there is a very common problem in veterinary medicine: the increase in the number of cases of drug poisoning. Thus, the aim of the present study was to group toxicological characteristics of some of the main drugs usually available in the home of tutors, turning it into a booklet for dissemination to the general public. Made from the reading of scientific articles, doctoral theses, master’s dissertations, course papers and books that contained information on the subject in question, the booklet takes information to the tutor about medicines that can cause intoxication in dogs and cats in a didactic form and with accessible language, considering that this is a situation which commonly affects several animals in home environment. The expectation is that with the booklet, reports of cases of drug intoxication in companion animals may decrease gradually.

Food poisoning causes and prevention and what to know about hygiene

Food-borne diseases are the most common health problems globally, and they are particularly common in Third World countries like India due to poor public sanitation and hygiene. Broadly speaking, food poisoning refers to any illness brought on by eating food that contains bacteria or non-bacterial substances. Stated differently, it's an acute instance of gastroenteritis caused by ingesting chemicals-contaminated food or drink, animal or plant-derived poisons, or living microbes and their toxins. Acute gastroenteritis is one of the leading causes of morbidity and mortality. The most vulnerable are newborns and young children. The clinical symptoms of a foodborne infection are determined by the pathogenic mechanisms that underlie it. The main symptoms are headache, nervousness, intense thirst, abrupt vomiting, diarrhea, colicky discomfort, cold, clammy skin, slow heartbeat, rigours, and cramps. The provision of clean, drinkable water, appropriate disposal of human and animal sewage with isolation from water supplies, and fundamental food hygiene standards are all very effective ways to prevent the development of these disorders.