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Heike Prohl - One of the best experts on this subject based on the ideXlab platform.
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Mate Choice versus Mate Preference: Inferences about Color-Assortative Mating Differ between Field and Lab Assays of Poison Frog Behavior
The American Naturalist, 2019Co-Authors: Yusan Yang, Matthew B. Dugas, Corinne L. Richards-zawacki, Simone Blomenkamp, Heike ProhlAbstract:AbstractCodivergence of mating traits and mate preferences can lead to behavioral isolation among lineages in early stages of speciation. However, mate preferences limit gene flow only when expressed as mate choice, and numerous factors might be more important than preferences in nature. In the extremely color polytypic strawberry poison frog (Oophaga pumilio), female mate preferences have codiverged with color in most allopatric populations tested. Whether these lab-assayed preferences predict mating (gene flow) in the wild remains unclear. We observed courting pairs in a natural contact zone between red and blue lineages until oviposition or courtship termination. We found color-assortative mating in a disturbed habitat with high population density but not in a secondary forest with lower density. Our results suggest color-assortative O. pumilio mate choice in the wild but also mating patterns that do not match those predicted by lab-assayed preferences.
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Mating status correlates with dorsal brightness in some but not all poison frog populations
Ecology and Evolution, 2017Co-Authors: Corinna E. Dreher, Molly E. Cummings, Ariel Rodríguez, Heike ProhlAbstract:Sexual signals are important for intraspecific communication and mate selection, but their evolution may be driven by both natural and sexual selection, and stochastic processes. Strawberry poison frogs (Oophaga pumilio) show strong color divergence among populations, but coloration also varies among individuals of the same population. The importance of coloration for female mate choice has been studied intensely, and sexual selection seems to affect color divergence in strawberry poison frogs. However, the effect of coloration on mating success under field conditions has received very little attention. Furthermore, few studies examined how phenotypic variation among individuals of the same color morph affects mate selection under natural conditions. We measured the spectral reflectance of courting and noncourting individuals and their background substrates in three geographically separated populations. In one population (Sarapiqui, Costa Rica), we found that naturally occurring courting pairs of males and females had significantly brighter dorsal coloration than individual males and females not engaged in courtship interactions. Our field observations suggest that, in the wild, females prefer brighter males while the reason for the higher courtship activity of brighter females remains unclear. Overall our results imply that brightness differences among individuals of the same color morph may actually affect reproductive success in some populations of strawberry poison frogs.
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The effects of background coloration and dark spots on the risk of predation in poison frog models
Evolutionary Ecology, 2017Co-Authors: Kathleen Preißler, Heike ProhlAbstract:Protective coloration is a well-known predator avoidance strategy in prey species. Aposematic species often display a contrasting color pattern consisting of dark spots of different shapes and sizes on a bright background coloration. Both elements, background color and spots are expected to serve different purposes. While the ecological function of the bright coloration has been addressed in many studies, the question of whether the interaction with differently sized spots influences predator behavior has received less attention by researchers. In a lowland rain forest in Costa Rica we used 2700 clay models that imitated the polytypic strawberry poison frog ( Oophaga pumilio ) as a proxy for an aposematic prey species. We manipulated the dorsal color pattern by using a local and a non-local aposematic and a non-local cryptic background color and combined them with black spots increasing in size (none, small, medium, large). The major objective was to test if spot size alters the survival rate of differently colored models. Background coloration and spot size were significant predictors of being attacked. However, the interaction between both effects was not. During five trials predators avoided the non-local aposematic color morph and did not discriminate between local aposematic and non-local cryptic models. Spot size and attack rate were negatively linear correlated which suggests that predator selection promotes the evolution of dark spots. We further conclude that spot size matters in a contrasting color pattern and plays an important role in predator avoidance.
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ecologia y comportamiento de las ranas venenosas del genero Oophaga en costa rica y panama
Alytes; 32(32) pp 31-45 (2015), 2015Co-Authors: Heike Prohl, Beatriz Willink CastroAbstract:The poison dart frogs Oophaga granulifera and Oophaga pumilio are distributed in Nicaragua (only O. pumilio), Costa Rica and Panama. The ecology and behavior of both species has attracted scientifc attention for several reasons. These frogs exhibit toxicity in combination with bright coloration and diversification into different color morphs. Moreover, they display highly aggressive and territorial behavior, and have a complex mating and parental care system. In this article we summarize recent published data from numerous researchers. We emphasize the link between the behavior (reproduction, territoriality) of the frogs and their resource and habitat use. Additionally we demonstrate how within species variation in the strategies used for predator avoidance (aposematism and crypsis) is associated with the genetic population structure, and correlated with behavioral divergence. We conclude that evolutionary forces like natural and sexual selection have contributed to diversification within the species and that these processes might result in the formation of new species. These evolutionary processes involved in speciation need more attention in conservation planning. (Less)
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Conspicuous displays in cryptic males of a polytypic poison-dart frog
Behavioral Ecology and Sociobiology, 2014Co-Authors: Beatriz Willink, Federico Bolaños, Heike ProhlAbstract:The evolution of aposematism is linked to increased opportunities for conspicuous sexual displays since detection by potential predators is no longer disadvantageous. Therefore, phenotypic divergence in aposematic species leading to relatively cryptic forms is expected to constrain such opportunities, by restoring the trade-off between natural and sexual selection on the boldness of sexual displays. We asked if and how a derived phenotype of the poison-dart frog Oophaga granulifera that appears relatively cryptic to potential predators exhibits conspicuous sexual displays for potential mates. We used visual modeling of frog contrasts against their natural backgrounds to test if for conspecifics green frogs appear less conspicuous than red frogs as they do for birds. We conducted behavioral observations of focal red and green males to determine if green frogs adjust their display behavior to the availability of potential mates. Dorsal brightness is known to influence female preferences in at least one poison frog species. We found that, despite being less visible under some measures, green frogs may appear as bright as red frogs for conspecifics but not birds, when viewed on dark backgrounds. Additionally, green males called more intermittently than red males when advertising to distant females, but they exhibited a dramatic increase in calling activity in proximity of a female and were as active as red males in this context. Together, our results suggest that green frogs retain context-dependent conspicuousness to conspecifics despite the evolution of relative crypsis to potential predators.
Ralph A Saporito - One of the best experts on this subject based on the ideXlab platform.
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Geographically separated orange and blue populations of the Amazonian poison frog Adelphobates galactonotus (Anura, Dendrobatidae) do not differ in alkaloid composition or palatability
Chemoecology, 2019Co-Authors: Adriana M. Jeckel, Ralph A Saporito, Sophie Kocheff, Taran GrantAbstract:As is typical of chemically defended animals, poison frogs present high variability in their alkaloid-based defenses. Previous studies have shown that geographically separated color morphs of Oophaga and Dendrobates species differ in both alkaloid composition and arthropod palatability. Here, we tested the generality of that finding by studying the alkaloid composition and palatability of geographically separated blue and orange morphs of the splash-backed poison frog, Adelphobates galactonotus . We identified and quantified the alkaloid composition of each individual frog using gas chromatography–mass spectrometry and evaluated the palatability of individual secretions to arthropods conducting feeding trials with Drosophila melanogaster . Despite their conspicuous differences in color and separation on opposite sides of a large aquatic barrier, the two morphs did not differ in alkaloid composition or palatability. This result shows that both color morphs are equally chemically protected and suggests that the color variation is not driven by predator selection.
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Experimental evidence for maternal provisioning of alkaloid defenses in a dendrobatid frog
Toxicon, 2019Co-Authors: Ralph A Saporito, Matthew W. Russell, Corinne L. Richards-zawacki, Matthew B. DugasAbstract:Abstract Dendrobatid frogs sequester alkaloid defenses from dietary arthropods. Here, we provide experimental evidence that mother strawberry poison frogs (Oophaga pumilio) provision alkaloids to tadpoles. Captive-raised females were fed the synthetic alkaloid decahydroquinoline (DHQ), which we subsequently quantified in their skin, eggs, and developing tadpoles. DHQ quantity was positively associated with tadpole mass/development, suggesting high sequestration rates by tadpoles. These data confirm that tadpoles obtain nutrition and alkaloids by feeding exclusively on maternally provisioned eggs.
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Behavioural preference for low levels of UV-B radiation in two neotropical frog species from Costa Rica
Journal of Tropical Ecology, 2018Co-Authors: Joseph A. Demarchi, Andrew Britton, Kaylee O'donnell, Ralph A SaporitoAbstract:Tropical frogs experience damaging effects from exposure to UV-B radiation, and some diurnally active, conspicuous species exhibit avoidance behaviours to high levels of UV-B. To determine if similar behaviours are present in other diurnal frogs, we experimentally compared UV-B avoidance in two common species of neotropical diurnal frogs – Oophaga pumilio , an aposematic poison frog and Craugastor bransfordii , a cryptic leaf-litter frog – in response to different levels of UV-B. Wild-caught frogs were tested in experimental arenas fitted with filters that permitted two different levels of UV-B (low: 14% vs. high: 84% UV-B). Both species spent significantly more time under the low UV-B filter, suggesting that behavioural preferences for lower levels of UV-B are common to different diurnal species. Furthermore, male O. pumilio significantly preferred lower levels of UV-B, whereas females did not exhibit a preference for lower UV-B, which may suggest differences in UV-B exposure or sensitivity and/or alternative mechanism(s) to avoid UV-B between sexes. Although limited in scope, the findings of our study suggest that UV-B avoidance may be a behavioural adaptation common to all diurnal frogs.
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Sequestered Alkaloid Defenses in the Dendrobatid Poison Frog Oophaga pumilio Provide Variable Protection from Microbial Pathogens
Journal of Chemical Ecology, 2018Co-Authors: Kyle J. Hovey, Erin E. Johnson, Emily M. Seiter, Ralph A SaporitoAbstract:Most amphibians produce their own defensive chemicals; however, poison frogs sequester their alkaloid-based defenses from dietary arthropods. Alkaloids function as a defense against predators, and certain types appear to inhibit microbial growth. Alkaloid defenses vary considerably among populations of poison frogs, reflecting geographic differences in availability of dietary arthropods. Consequently, environmentally driven differences in frog defenses may have significant implications regarding their protection against pathogens. While natural alkaloid mixtures in dendrobatid poison frogs have recently been shown to inhibit growth of non-pathogenic microbes, no studies have examined the effectiveness of alkaloids against microbes that infect these frogs. Herein, we examined how alkaloid defenses in the dendrobatid poison frog, Oophaga pumilio , affect growth of the known anuran pathogens Aeromonas hydrophila and Klebsiella pneumoniae . Frogs were collected from five locations throughout Costa Rica that are known to vary in their alkaloid profiles. Alkaloids were isolated from individual skins, and extracts were assayed against both pathogens. Microbe subcultures were inoculated with extracted alkaloids to create dose-response curves. Subsequent spectrophotometry and cell counting assays were used to assess growth inhibition. GC-MS was used to characterize and quantify alkaloids in frog extracts, and our results suggest that variation in alkaloid defenses lead to differences in inhibition of these pathogens. The present study provides the first evidence that alkaloid variation in a dendrobatid poison frog is associated with differences in inhibition of anuran pathogens, and offers further support that alkaloid defenses in poison frogs confer protection against both pathogens and predators.
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escape behaviour of aposematic Oophaga pumilio and cryptic craugastor sp frogs in response to simulated predator approach
Journal of Tropical Ecology, 2017Co-Authors: Annelise Blanchette, Noemi Becza, Ralph A SaporitoAbstract:Crypsis and aposematism are common antipredator strategies that can each be coupled with behaviours that maximize predator deterrence or avoidance. Cryptic animals employ camouflage to conceal themselves within their environment and generally rely on immobility to avoid detection by predators. Alternatively, aposematic animals tend to rely on an association between conspicuous colouration and secondary defence to deter potential predators, and tend to exhibit slow movements in response to predators. The goal of the present study was to determine how cryptic Craugastor sp. and aposematic Oophaga pumilio respond to simulated human and bird model predators. Oophaga pumilio responded more often with movement to both the human (17/22) and bird (9/25) predators than Craugastor sp. (human: 2/21; bird: 0/21). The increased movement resulted in a greater average flight initiation distance, latency to move, and distance fled in O. pumilio . These findings suggest that cryptic Craugastor sp. rely on immobility to avoid detection, whereas aposematic O. pumilio utilize movement, possibly as a mechanism to increase the visibility of their warning signals to potential predators. Furthermore, O. pumilio exhibited greater movement in response to humans, suggesting that they actively avoid trampling by large threats, rather than considering them predators.
Adolfo Amézquita - One of the best experts on this subject based on the ideXlab platform.
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Genetic differentiation and overexploitation history of the critically endangered Lehmann’s Poison Frog: Oophaga lehmanni
Conservation Genetics, 2020Co-Authors: Mileidy Betancourth-cundar, Pablo Palacios-rodríguez, Daniel Mejía-vargas, Adolfo AmézquitaAbstract:Species conservation with fragmented and endangered populations must be based on a prior and thorough knowledge of the structure and population dynamics. Oophaga lehmanni is a dendrobatid species endemic of Colombia and is restricted to its type locality. This species has a fragmented distribution and is considered as critically endangered mainly due to habitat destruction and overexploitation. Oophaga lehmanni exhibits phenotypic variation in the dorsal color pattern (red and yellow morphs). We reconstructed the overexploitation history that this species has faced in the last 40 years. In addition, we collected genetic and morphological data for the first time in natural populations to describe genetic diversity between and within populations, and to evaluate morphological and genetic differences between red and yellow morphs. Overexploitation data suggest that more than 80.000 (Min = 60.047–Max = 102.236) frogs were extracted from the field in the last four decades, probably generating the local extirpation or population decline from the type locality. Genetic data showed reduced genetic diversity. Observed heterozygosity (mean ± s.d. = 0.599 ± 0.165) is lower than expected (mean ± s.d. = 0.867 ± 0.082). We did not find differences in body size and heterozygosity between the two morphs; however, individuals analyzed were assigned to two genetic clusters, which corresponded to the O. lehmanni -yellow and O. lehmanni -red. In addition, F_ST (0.209) and Nei genetic distance (0.18) values indicated genetic differentiation between the two morphs; therefore, red and yellow morphs should be treated as independent management units. This information will help to define appropriate and long-term conservation units, as a useful tool to mitigate the extinction risk of this species.
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genetic differentiation and overexploitation history of the critically endangered lehmann s poison frog Oophaga lehmanni
Conservation Genetics, 2020Co-Authors: Mileidy Betancourthcundar, Pablo Palaciosrodriguez, Daniel Mejiavargas, Adolfo AmézquitaAbstract:Species conservation with fragmented and endangered populations must be based on a prior and thorough knowledge of the structure and population dynamics. Oophaga lehmanni is a dendrobatid species endemic of Colombia and is restricted to its type locality. This species has a fragmented distribution and is considered as critically endangered mainly due to habitat destruction and overexploitation. Oophaga lehmanni exhibits phenotypic variation in the dorsal color pattern (red and yellow morphs). We reconstructed the overexploitation history that this species has faced in the last 40 years. In addition, we collected genetic and morphological data for the first time in natural populations to describe genetic diversity between and within populations, and to evaluate morphological and genetic differences between red and yellow morphs. Overexploitation data suggest that more than 80.000 (Min = 60.047–Max = 102.236) frogs were extracted from the field in the last four decades, probably generating the local extirpation or population decline from the type locality. Genetic data showed reduced genetic diversity. Observed heterozygosity (mean ± s.d. = 0.599 ± 0.165) is lower than expected (mean ± s.d. = 0.867 ± 0.082). We did not find differences in body size and heterozygosity between the two morphs; however, individuals analyzed were assigned to two genetic clusters, which corresponded to the O. lehmanni-yellow and O. lehmanni-red. In addition, FST (0.209) and Nei genetic distance (0.18) values indicated genetic differentiation between the two morphs; therefore, red and yellow morphs should be treated as independent management units. This information will help to define appropriate and long-term conservation units, as a useful tool to mitigate the extinction risk of this species.
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hybridization promotes color polymorphism in the aposematic harlequin poison frog Oophaga histrionica
Ecology and Evolution, 2013Co-Authors: Iliana Medina, Ian J. Wang, Camilo Salazar, Adolfo AmézquitaAbstract:Whether hybridization can be a mechanism that drives phenotypic diversity is a widely debated topic in evolutionary biology. In poison frogs (Dendrobatidae), assortative mating has been invoked to explain how new color morphs persist despite the expected homogenizing effects of natural selection. Here, we tested the complementary hypothesis that new morphs arise through hybridization between different color morphs. Specifically, we (1) reconstructed the phylogenetic relationships among the studied populations of a dart-poison frog to provide an evolutionary framework, (2) tested whether microsatellite allele frequencies of one putative hybrid population of the polymorphic frog O. histrionica are intermediate between O. histrionica and O. lehmanni, and (3) conducted mate-choice experiments to test whether putatively intermediate females prefer homotypic males over males from the other two populations. Our findings are compatible with a hybrid origin for the new morph and emphasize the possibility of hybridization as a mechanism generating variation in polymorphic species. Moreover, because coloration in poison frogs is aposematic and should be heavily constrained, our findings suggest that hybridization can produce phenotypic novelty even in systems where phenotypes are subject to strong stabilizing selection.
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stream noise hybridization and uncoupled evolution of call traits in two lineages of poison frogs Oophaga histrionica and Oophaga lehmanni
PLOS ONE, 2013Co-Authors: Fernando Vargassalinas, Adolfo AmézquitaAbstract:According to the acoustic adaptation hypothesis, communication signals are evolutionary shaped in a way that minimizes its degradation and maximizes its contrast against the background noise. To compare the importance for call divergence of acoustic adaptation and hybridization, an evolutionary force allegedly promoting phenotypic variation, we compared the mate recognition signal of two species of poison frogs (Oophaga histrionica and O. lehmanni) at five localities: two (one per species) alongside noisy streams, two away from streams, and one interspecific hybrid. We recorded the calls of 47 males and characterized the microgeographic variation in their spectral and temporal features, measuring ambient noise level, body size, and body temperature as covariates. As predicted, frogs living in noisy habitats uttered high frequency calls and, in one species, were much smaller in size. These results support a previously unconsidered role of noise on streams as a selective force promoting an increase in call frequency and pleiotropic effects in body size. Regarding hybrid frogs, their calls overlapped in the signal space with the calls of one of the parental lineages. Our data support acoustic adaptation following two evolutionary routes but do not support the presumed role of hybridization in promoting phenotypic diversity.
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Field but not lab paradigms support generalisation by predators of aposematic polymorphic prey: the Oophaga histrionica complex
Evolutionary Ecology, 2013Co-Authors: Adolfo Amézquita, Laura Castro, Mónica Arias, Mabel González, Carolina EsquivelAbstract:The persistence of novel aposematic forms, and thereby the evolution of aposematic polymorphism, remain intriguing. Novel and rare forms could be disproportionally attacked by predators that already learned to avoid a pre-existing and more common aposematic form. Alternatively, novel forms could be less frequently attacked if predators are reluctant to attack unknown potential prey (neophobia) or if previous learning allows them to generalise and recognise the novel form as toxic. We used colour variation in polymorphic poison frogs ( Oophaga histrionica complex) to test whether predators familiar with one aposematic form do generalise their avoidance behaviour to other aposematic forms. To strengthen our inference, we combined a field test of attack rates to local and non-local models with a lab experiment of generalisation capabilities by newly born chicks. Field predators attacked a significantly lower proportion of 529 aposematic compared to 150 cryptic models. Predators co-occurring with the local aposematic form of O. histrionica equally avoided non-local forms, especially in areas where the species was abundant. Forty-two lab chicks learned to discriminate between an aposematic and a cryptic image, but failed to generalise to other aposematic images, even though we tried with six combinations of aposematic forms. To better mimic the situation in the field, we further tested whether chicks trained with a set of four simultaneous aposematic images would generalise better. They failed to learn the discrimination task. Our data contrast with previous field studies on other poison frogs, and support a role for generalisation, and arguably not neophobia, in predator avoidance of novel aposematic forms.
Craig M Young - One of the best experts on this subject based on the ideXlab platform.
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effects of the oophagous bivalve acesta Oophaga on the morphology and fecundity of its deep sea tubeworm host lamellibrachia luymesi
Marine Ecology, 2014Co-Authors: Zair P Burris, Joshua P Lord, Craig M YoungAbstract:The deep-sea bivalve Acesta Oophaga lives attached to the anterior end of the vestimentiferan tubeworm, Lamellibrachia luymesi, at cold methane seeps. The bivalve is found almost exclusively on female tubeworms, where it consumes the lipid-rich eggs of L. luymesi that are spawned year round (Biological Bulletin, 209, 2005, 87). It is apparent that A. Oophaga benefits directly from this close association, but the consequences for the tubeworm host may be more complicated than just a simple predator–prey interaction. Since A. Oophaga completely surrounds the tube opening and plume of the worm, it is likely that its presence would limit oxygen uptake by L. luymesi, thereby inhibiting worm growth and reproduction. We hypothesized that occupied tubeworms would compensate for this by growing larger plumes for oxygen uptake. To explore the effects of bivalve presence/absence on female tubeworms, several morphological features, including body size, plume length, tube diameter, and tube segment length, as well as instantaneous fecundity, were compared. Results suggest that the mere presence of A. Oophaga has a significant impact on the morphology of its host worm, as all measures of worm size, except for tube segment length, were significantly greater with clams present. Additionally, instantaneous fecundity was 3.5 times higher in occupied worms, implying that tubeworms are not oxygen-deprived or energy limited as a result of bivalve presence. Our findings suggest that the association between these two deep-sea organisms may be a more complex form of symbiosis than the simple predator–prey relationship, as previously thought.
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Effects of the oophagous bivalve Acesta Oophaga on the morphology and fecundity of its deep‐sea tubeworm host, Lamellibrachia luymesi
Marine Ecology, 2013Co-Authors: Zair P Burris, Joshua P Lord, Craig M YoungAbstract:The deep-sea bivalve Acesta Oophaga lives attached to the anterior end of the vestimentiferan tubeworm, Lamellibrachia luymesi, at cold methane seeps. The bivalve is found almost exclusively on female tubeworms, where it consumes the lipid-rich eggs of L. luymesi that are spawned year round (Biological Bulletin, 209, 2005, 87). It is apparent that A. Oophaga benefits directly from this close association, but the consequences for the tubeworm host may be more complicated than just a simple predator–prey interaction. Since A. Oophaga completely surrounds the tube opening and plume of the worm, it is likely that its presence would limit oxygen uptake by L. luymesi, thereby inhibiting worm growth and reproduction. We hypothesized that occupied tubeworms would compensate for this by growing larger plumes for oxygen uptake. To explore the effects of bivalve presence/absence on female tubeworms, several morphological features, including body size, plume length, tube diameter, and tube segment length, as well as instantaneous fecundity, were compared. Results suggest that the mere presence of A. Oophaga has a significant impact on the morphology of its host worm, as all measures of worm size, except for tube segment length, were significantly greater with clams present. Additionally, instantaneous fecundity was 3.5 times higher in occupied worms, implying that tubeworms are not oxygen-deprived or energy limited as a result of bivalve presence. Our findings suggest that the association between these two deep-sea organisms may be a more complex form of symbiosis than the simple predator–prey relationship, as previously thought.
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spermatozoon structure of acesta Oophaga limidae a cold seep bivalve
Invertebrate Reproduction & Development, 2013Co-Authors: Alan N Hodgson, Kevin J Eckelbarger, Valerie Hodgson, Craig M YoungAbstract:The structure of the spermatozoon of Acesta Oophaga (Bivalvia) is described by transmission electron microscopy. This cold-seep species produces ect-aquasperm, confirming that it is a broadcast spawner. The head of the sperm consists of a small, rounded, electron-dense nucleus, capped by a short conical acrosome, the contents of which are differentiated. The mid-piece contains a pair of orthogonally arranged centrioles surrounded by five spherical mitochondria. The gonad of one individual contained eggs and sperm, which supports the hypothesis that A. Oophaga is a sequential hermaphrodite.
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Four genes, morphology and ecology: distinguishing a new species of Acesta (Mollusca; Bivalvia) from the Gulf of Mexico
Marine Biology, 2007Co-Authors: Johanna Järnegren, Christoffer Schander, Jon-arne Sneli, Vera Rønningen, Craig M YoungAbstract:There is currently an active scientific debate about the most correct and efficient way to identify species. To date, few studies in the marine realm have combined the available taxonomic methods. In this study we have used morphology, ecology and molecular analyses to identify a new species within the bivalve genus Acesta . All four genes studied (12S, 16S, Cytb, COI) suggested that a common cold-seep species in the Gulf of Mexico, A. bullisi , should be divided into two distinct species. This conclusion was supported by morphological traits and by observations of ecological distribution. A. Oophaga Järnegren, Schander and Young n. sp. is described here, and A. bullisi Vokes (Tulane Stud Geol 2:75–92, 1963 ) is re-described. This study shows that DNA barcoding in combination with traditional morphological and ecological analyses may be an important tools to identify hidden biodiversity among deep-water organisms such as bivalves.
Jose A Andres - One of the best experts on this subject based on the ideXlab platform.
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complex patterns of differentiation and gene flow underly the divergence of aposematic phenotypes in Oophaga poison frogs
Molecular Ecology, 2020Co-Authors: Jana Ebersbach, Andres Possoterranova, Jose A Andres, Steven M Bogdanowicz, Monica Gomezdiaz, Ma Ximena Garciagonzalez, Wilmar BolivargarciaAbstract:Hybridization and introgression can have complex consequences for both species evolution and conservation. Here, we investigated the origin and characteristics of a putative hybrid zone between two South American poison dart frog species, Oophaga anchicayensis and the critically endangered Oophaga lehmanni, which are heavily sought after on the illegal pet market. Using a combination of phenotypic (49 traits) and genomic (ddRADseq) data, we found that the putative hybrids are morphologically distinct from their parental species and confirmed genomic signatures of admixture in these populations. Several lines of evidence (hybrid indices, interspecific hybrid heterozygosity, genomic clines, comparisons with simulated hybrids and demographic modelling) support the conclusion that these populations are not comprised of early-generation hybrids and thus, they probably did not arise as a result of illegal translocations associated with wildlife trafficking. Instead, they probably represent an independent lineage which has persisted through isolation and has only relatively recently re-established gene flow with both parental species. Furthermore, we detected signals of differential introgression from parental species into these hybrid populations which suggest relaxed stabilizing selection on these aposematic colour morphs, potentially via context-dependent female choice. These populations thus provide a fascinating window into the role of hybridization, isolation and female choice in the diversification of South American poison dart frogs. In addition, our results underline the importance of landscape conservation measures to protect, not only known localities of nominal species, but also the phenotypic and genomic variation harbored by admixed lineages which represent crucial repositories for the impressive diversity in this system.
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genetic bases of aposematic traits insights from the skin transcriptional profiles of Oophaga poison frogs
bioRxiv, 2019Co-Authors: Andres Mauricio Possoterranova, Jose A AndresAbstract:Aposematic organisms advertise their defensive toxins to predators using a variety of warning signals, including bright coloration. While most Neotropical poison frogs (Dendrobatidae) rely on crypsis to avoid predators, Oophaga poison frogs from South America advertise their chemical defenses, a complex mix of diet-derived alkaloids, by using conspicuous hues. The present study aimed to characterize the skin transcriptomic profiles of the South American clade of Oophaga poison frogs (O. anchicayensis, O. solanensis, O. lehmanni and O. sylvatica). Our analyses showed very similar transcriptomic profiles for these closely related species in terms of functional annotation and relative abundance of gene ontology terms expressed. Analyses of expression profiles of Oophaga and available skin transcriptomes of cryptic anurans allowed us to propose possible mechanisms for the active sequestration of alkaloid-based chemical defenses and to highlight some genes that may be potentially involved in resistance mechanisms to avoid self-intoxication and skin coloration. In doing so, we provide an important molecular resource for the study of warning signals that will facilitate the assembly and annotation of future poison frog genomes.
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Multivariate species boundaries and conservation of harlequin poison frogs
Molecular Ecology, 2018Co-Authors: Andrés Posso-terranova, Jose A AndresAbstract:In this study, we present an iterative method for delimiting species under the general lineage concept (GLC) based on the multivariate clustering of morphological, ecological and genetic data. Our rationale is that distinct multivariate groups correspond to evolutionarily independent metapopulation lineages because they reflect the common signal of different secondary defining properties (environmental and genetic distinctiveness, phenotypic diagnosability, etc.) that imply the existence of barriers preventing or limiting gene exchange. We applied this method to study a group of endangered poison frogs, the Oophaga histrionica complex. In our study case, we used next-generation targeted amplicon sequencing to obtain a robust genetic data set that we combined with patterns of morphological and ecological features. Our analyses revealed the existence of at least five different species in the histrionica complex (three, new to science), some of them, occurring in small isolated populations outside any protected areas. The lineage delimitation proposed here has important conservation implications as it revealed that some of the Oophaga species should be considered among the most vulnerable of the Neotropical frogs. More broadly, our study exemplifies how multiple-amplicon and multivariate statistical techniques can be integrated to successfully identify species and their boundaries.
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Diversification and convergence of aposematic phenotypes: truncated receptors and cellular arrangements mediate rapid evolution of coloration in harlequin poison frogs
Evolution, 2017Co-Authors: Andrés Posso-terranova, Jose A AndresAbstract:Aposematic signals represent one of the classical systems to study evolution and, as such, they have received considerable empirical and theoretical investigation. Despite the extensive literature on aposematic coloration, much uncertainty remains about genetic changes responsible for the repeated evolution of similar signals in multiple lineages. Here, we study the diversification and convergence of coloration among lineages of aposematic harlequin poison frogs (Oophaga histrionica complex). Our results suggest that different background phenotypes, showing different color and/or luminance contrast, have evolved independently at least twice in this group. We suggest that cellular arrangements are behind the striking diversity of color and patterns in this group and propose that differences in dorsal background color may be related to either or both, the presence/absence of xanthophores and the dispersion of melanosomes. Our genetic analyses support a role for the melanocortin receptor MC1R in melanosome aggregation, and we show evidence that two different mutations (∆433 and C432A) are responsible for the darker phenotypes that may display a more detectable, easier to learn, aposematic signal.
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complex niche divergence underlies lineage diversification in Oophaga poison frogs
Journal of Biogeography, 2016Co-Authors: Andres Possoterranova, Jose A AndresAbstract:Aim Despite the incredible diversity of lowland tropical rain forests, we still have limited understanding of the drivers of speciation in these ecoregions. Here, we investigated the relative contribution of geographical and environmental factors to the diversification of a Neotropical genus of poison frogs (Oophaga). Location Central and South America, including regions from southern Nicaragua to northern Ecuador. Methods We generated gene genealogies (12S, 16S, COI, CytB and tRNA-val, SIAH1, H3 and Rag1) and used species phylogenetic methods (MDC and *beast) to generate a robust phylogeny of Oophaga frogs. Then, we combined the resulting phylogenetic hypothesis with detailed geographical data and environmental niche modelling (ENM) to test the role of geographical isolation, climatic niche divergence and altitudinal gradients. Results Gene genealogies were discordant and did not show exclusive genealogical patterns; however, species tree resolved the phylogenetic relationship among Oophaga species with strong node support (> 0.9 ML/BPP). Geographical ranges showed little overlap between distantly related species. However, within the South American and Central American clades, sister taxa showed substantially overlapping ranges. Analyses of ecological disparity (DTT) indicated a departure from a neutral (Brownian) model of evolution, and age-range correlations, predicted niche occupancy profiles, and Seeva analyses showed that different species tend to evolve under different potential climatic niches. Main conclusions Oophaga frogs originated in Central America and reached South America after the closure of the Panama Isthmus. The South- and Central-American clades of this genus have convergently evolved to similar patterns of geographical distribution and niche occupancy. Within clades, sister taxa showed parapatric distributions replacing each other along elevational gradients as predicted by the models of divergence along continuous ecological gradients. Accordingly, we found strong shifts in climatic niches throughout the history of these two clades. However, the largest niche shifts seem to post-date the final elevation of the Talamanca and northern Andes. Overall, our data suggest that speciation along climatic gradients on a structured landscape has been a major evolutionary force behind the diversification of Oophaga poison frogs.
