Verhaltensökologie und Persönlichkeit bei Pfeilgiftfröschen

Drittmittelprojekt: DAAD, 24.705 EUR

Kliniken/Institute:
Institut für Zoologie

Projektdetails:
Aposematism and crypsis are contrasting antipredator strategies. In the color polymorphic Oophaga pumilio, phylogenetic analyses have shown that populations with cryptic and aposematic coloration might have evolved independently in different islands. Two other species, O. granulifera and O. vicentei also display cryptic and aposematic color morphs in geographically isolated populations. Particularly, phylogenetic analyses of the evolution of these contrasting antipredator strategies can improve our understanding on the evolution of polymorphism in aposematic species. This project aims to uncover the molecular signatures of selection present in the genes of three Oophaga species that experienced independently evolved cryptic and aposematic phenotypes. To this effect, we look forward to elucidate the phylogenetic relationships of the genus and quantify the variation in gene expression and allelic frequencies using state-of-the-art methods.

Kooperationspartner:

Dr. Evan Towney, Goethe Universität Frankfurt, Biologicum

Drittmittelprojekt: DFG, 242.660 EUR

Kliniken/Institute:
Institut für Zoologie
Institut für Pathologie

Projektdetails:
Aposematismus ist die Assoziation zwischen einer auffälligen Warnfärbung und einem Abwehrmechanismus (z. B. Gifte) zur Vermeidung von Prädation. Die Genetik der Färbung und der Giftigkeit bei aposematischen Tieren ist noch nicht gut erforscht. In diesem Zusammenhang ist die Vielfalt der Farbmuster und der Alkaloide in der Haut, die mit Strategien zur Vermeidung von Raubtieren bei neotropischen Giftfröschen verbunden sind, eine exzellente Gelegenheit, die Konvergenz der ökologischen Anpassung zu untersuchen. Pfeilgiftfrösche unterscheiden sich in ihren Farbmustern und ihrer Toxizität zwischen den Populationen und es gibt starke Beweise dafür, dass Aposematismus adaptiv ist, wahrscheinlich angetrieben durch die Selektion von Raubtieren. Für den Erdbeerfrosch Oophaga pumilio konnten wir für Gene, die im Zusammenhang mit dem Pigment-Metabolismus stehen (z.B. Pteridingene), zeigen, dass sie zwischen Farbmorphen unterschiedlich stark exprimiert sind. Nächstes Ziel ist es, den Aufbau pigmenthaltiger Zellen (Chromatophoren), die chromatographische Charakterisierung von Farbpigmenten und Alkaloiden, Expressionsmuster von Genen, die an der Färbung und Giftigkeit beteiligt sind, für drei farbpolymorphe, neotropischer Pfeilgiftfrösche der Gattung Oophaga in Verbindung zu setzen.
Für dieses Projekt werden wir Haut- und Leberproben von acht Populationen mit entweder grüner oder roter Färbung in Panama und Costa Rica sammeln. Zusammen mit Mitarbeitern der Universidad de Costa Rica, der TiHo, der University of Cambridge und des STRI in Panama werden wir die Chromatophoren in der Haut elektronenmikroskopisch charakterisieren, die Farbpigmente und Toxine in der Haut gaschromatographisch analysieren und eine RNAseq-Analyse mit dorsaler Haut durchführen. Wir erwarten, dass die Expressionsniveaus von Genen im Pigment- (z.B. Carotinoide) und Alkaloidmetabolismus zwischen verschiedenen Farbmorphen (rot vs. grün) variieren, aber aufgrund der Konvergenz innerhalb der Farbmorphen zwischen den Arten ähnlich sind. Unsere Studie wird zu einem besseren Verständnis des Zusammenhangs zwischen Geno- und Phänotypen adaptiver Anti-Räuber-Strategien führen und die Evolution regulatorischer Mechanismen der Genexpression beleuchten.

Resultate:

Monteiro JPC, Ibáñez R, Mantzana-Oikonomaki V, Pröhl H, Rodríguez A. 2023. Genetic diversity of Oophaga vicentei (Anura: Dendrobatidae) and taxonomic position of a remarkable color morph from Panama.Salamandra 59:347-351.

Kooperationspartner:

Dr. Giselle Tamayo, UCR, Costa Rica

Dr. Beatriz Willink, UCR, Costa Rica

Dr. Nicolas Mundy, University of Cambridge, UK

Dr. Roberto Ibañéz, STRI, Panama

Drittmittelprojekt: Smithsonian Tropical Research Institute, Panama Secretaria Nacional de Ciencia y Tecnologia, Panama, 18.000 EUR

Kliniken/Institute:
Institut für Zoologie

Projektdetails:
The evolution of different forms of parental care is an important topic in behavioral ecology, and it involves complex suites of associated parental and offspring traits. For example, some parents provide nourishment or selection and protection of suitable nesting sites for offspring. Understanding how memory guides individuals to locate or return to a reproductive resource is one of the major challenges in studies of animal behavior. During parental care, poison frogs routinely transport their tadpoles from terrestrial clutches to suitable deposition sites, and some individuals return to supply their offspring with nutritive unfertilized eggs. Thus, these frogs rely on spatial memory to exploit resources important for successful reproduction. However, it is unknown how the spatial abilities are related to the parental care traits performed by an individual. The aim of this study is to investigate behavioral spatial strategies and their genetic basis in the strawberry poison-dart frog, Oophaga pumilio. To investigate the spatial strategies in the context of parental care we aim examining ability of females and males to find a goal in a plus maze under experimental conditions. Moreover, we will determine the possible genes involved in spatial learning through gene expression analysis (RNASeq) of the pallium, the brain region known to be involved in spatial learning. Since females perform most parental care duties involving navigation in large home ranges, we expect females to have better spatial abilities than males.

Kooperationspartner:

Dr. Roberto Ibañéz, Ph. D., Smithsonian Tropical Research Institute

Prof. Dr. Klaudia Witte, Universität Siegen

Drittmittelprojekt: Smithsonian Tropical Research Institute, Panama Secretaria Nacional de Ciencia y Tecnologia, Panama, 37.170 EUR

Kliniken/Institute:
Institut für Zoologie

Projektdetails:
Variation in biological traits is universal in natural populations and has significant evolutionary and ecological consequences. Behavioral traits or combinations of traits are important as they may affect the survival and reproductive success of individuals. Studies have shown that animal personalities and behavioral traits covary with ecological conditions, dependent on the state of the individual, and can be maintained by frequency dependent selection. Animal personalities have been often been classified along five behavioral axes, namely, shyness-boldness, exploration-avoidance, activity, aggressiveness, and sociability. Some studies have shown that amphibians display personality and behavioral traits. However, implications of animal personality in ecological context remain largely unexplored in amphibians. Neotropical poison frogs are toxic and diurnal amphibians with highly evolved parental care and territorial behavior. In this study, we will investigate behavioral traits and personality of the strawberry poison frog within and between populations that differ in their anti-predator strategy (level of aposematism). Therefore, we will examine variations in exploratory, risk-taking and aggressive behavior by running standardized laboratory-based trials on wild-caught adult O. pumilio. Each frog will be tested in three behavioral trials, with the following sequence: exploration, risk-taking and aggressiveness. Within a population, we expect individuals present variations in behavioral traits and personality, and that behavioral traits might be correlated (syndrome). Among populations we expect more aposematic frogs (brighter coloration, higher toxicity) to be more explorative, bold and aggressive than less aposematic frogs.

Kooperationspartner:

Roberto Ibanez, Ph. D., Smithsonian Tropical Research Institute, Panama

MSc. Carolina Esquivel, Universidad Nacional, Costa Rica

Drittmittelprojekt: DAAD, DGHT

Kliniken/Institute:
Institut für Zoologie

Projektdetails:
Die Pfeilgiftfrösche der Gattung Oophaga zeichnen sich durch ein komplexes Territorial-, Paarungs- und Brutpflegeverhalten aus. Aus diesem Grund sind sie Modellobjekte in vielen Studien zur Beantwortung evolutionsbiologischer Studien. Weiterhin sind die meisten dieser Arten polymorph, d.h. sie unterschieden sich in ihren bioakustischen Signalen, Farbmustern und anderen morphologischen Variablen zwischen den Populationen. Auf Grund dessen ist es häufig schwierig Arten klar abzugrenzen. Das Ziel dieses Projektes ist eine molekular-genetische Studie durchzuführen, in der Arten genetisch eindeutig zugeordnet werden können. Sobald dieses erfolgt ist, folgen weitere Untersuchungen, um herauszufinden in wie weit die Arten sich in ihren ökologischen Ansprüchen und ihrem Verhalten unterscheiden. Das Ziel des Projektes ist es Artbildungsmechamismen besser zu verstehen.

Resultate:

Galindo Uribe D, Sunyer J, Hauswaldt S, Amezquita A, Pröhl H, Vences M (2014) Color and pattern variation and Pleistocene phylogeographic origin of the strawberry poison frog, Oophaga pumilio, in Nicaragua. Salamandra, 50: 225-235

Brusa O, Bellati A, Meuche I, Mundy NI, Pröhl H (2013) Divergent evolution in the polymorphic granular poison-dart frog, Oophaga granulifera: genetics, colouration, advertisement calls and morphology. J Biogeogr 40:394-408

Hauswaldt JS, Ludewig A-K, Vences M, Pröhl H (2011) Widespread co-occurrence of divergent mitochondrial haplotype lineages in a Central American species of poison frog (Oophaga pumilio). J Biogeog 38: 711-726

Hagemann S, Pröhl H (2007) Mitochondrial paraphyly in a polymorphic poison frog species (Dendrobatidae; D. pumilio). Molecular Phylogenetics & Evolution 45: 740-747

Kooperationspartner:

Prof. Dr. Adolfo Amezquita, Universidad de los Andes

Dr. Diana Galindo, Universidad de los Andes

Prof. Dr. Miguel Vences, TU Braunschweig

Drittmittelprojekt: DFG, 27.210 EUR

Kliniken/Institute:
Institut für Zoologie

Projektdetails:
The genetics of colouration has been studied in mammals, birds, fish and reptiles but studies on amphibian are scarce. Besides extensive variability in colour pattern nothing is known about the underlying genetic components involved in creating colour diversity within and among amphibian species. In this context the diversity of colouration patterns linked to predator avoidance strategies in Neotropical poison frogs is an exciting opportunity to study the genetics of ecological adaptation. Poison frogs differ in colouration patterns among populations and strong evidence exists that colouration is adaptive, probably driven by predator selection. The objective of this project is to characterize the colour pigments and the colouration genes for the extremely colour polymorphic Neotropical strawberry poison frog Oophaga pumilio. In this frog bright aposematic as well as duller cryptic colour morphs are present in different Panamanian populations.
For our project we will collect skin samples from three populations diverged in colour patterns: a red one, a green one and a blue one. We will perform RNAseq analysis on dorsal skin-derived cDNA. cDNA samples will be send to a sequencing service that will perform next generation sequencing to analyse differences in expression levels in genes involved in colouration. We expect that genes involved in the carotenoid /pteridin uptake, synthesis or storage differ in their expression level among colour morphs. We will confirm results for loci with significant expression differences by performing quantitative Real time-RT-PCR (RT=reverse transcription). Thus, we will determine the key gene expression differences underlying colour variation in this species. Our study will lead to a better understanding of causes and consequences of adaptive colouration.

Resultate:

Rodríguez A, Mundy N, Ibáñez R, Pröhl H (2020) Being red, blue and green: the genetic basis of coloration differences in the strawberry poison frog (Oophaga pumilio). BMC Genomics: 21. 10.1186/s12864-020-6719-5.

Kooperationspartner:

Dr. Nicolas Mundy, University of Cambridge, UK

Dr. Roberto Ibañéz, STRI, Panama

Drittmittelprojekt: DFG, VW Stiftung, Eigenmittel

Kliniken/Institute:
Institut für Zoologie

Projektdetails:
Geographic variation in behaviour has becoming an important research topic within the last decade. Neotropical poison frogs often show diversification into different genetic lineages, variation in sexual signals as advertisement calls and divergence into different colour morphs. In this study we explore the relationship between genetic population structure, variation in advertisement calls and morphological traits such as size, weight and colour pattern and differences in reproductive and anti-predator behaviour in two poison frogs species: the strawberry poison frogs (Oophaga pumilio) and the granular poison frog (Oophaga garnulifera). Particularly interesting is the divergence into aposematic and cryptic colour morphs and we explore whether this divergence is related to more conspicuous and more cryptic behavioural elements. Finally we examine similarities in divergence patterns between the two species.

Kooperationspartner:

Beatriz Willink, Escuela de Biología, Universidad de Costa Rica,

MSc. Federico Bolaños, Escuela de Biología, Universidad de Costa Rica

Dr. Susanne Hauswaldt, TU Braunschweig