TY - JOUR A1 - Tobler, Michael A1 - Schlupp, Ingo A1 - Heubel, Katja U. A1 - Riesch, Rudiger A1 - Garcia de Leon, Francisco J. A1 - Giere, Olav A1 - Plath, Martin T1 - Life on the edge: hydrogen sulfide and the fish communities of a Mexican cave and surrounding waters JF - Extremophiles : life under extreme conditions N2 - Most eucaryotic organisms classified as living in an extreme habitat are invertebrates. Here we report of a fish living in a Mexican cave (Cueva del Azufre) that is rich in highly toxic H2S. We compared the water chemistry and fish communities of the cave and several nearby surface streams. Our study revealed high concentrations of H2S in the cave and its outflow (El Azufre). The concentrations of H2S reach more than 300 mu M inside the cave, which are acutely toxic for most fishes. In both sulfidic habitats, the diversity of fishes was heavily reduced, and Poecilia mexicana was the dominant species indicating that the presence of H2S has an all-or-none effect, permitting only few species to survive in sulfidic habitats. Compared to habitats without H2S, P. mexicana from the cave and the outflow have a significantly lower body condition. Although there are microhabitats with varying concentrations of H2S within the cave, we could not find a higher fish density in areas with lower concentrations of H2S. We discuss that P. mexicana is one of the few extremophile vertebrates. Our study supports the idea that extreme habitats lead to an impoverished species diversity. KW - extremophile teleosts KW - Poecilia mexicana KW - cave fish KW - hypoxia KW - chemoautotrophy KW - condition factor Y1 - 2006 U6 - https://doi.org/10.1007/s00792-006-0531-2 SN - 1431-0651 VL - 10 SP - 577 EP - 585 PB - Springer CY - Tokyo ER - TY - JOUR A1 - Schedina, Ina Maria A1 - Groth, Detlef A1 - Schlupp, Ingo A1 - Tiedemann, Ralph T1 - The gonadal transcriptome of the unisexual Amazon molly Poecilia formosa in comparison to its sexual ancestors, Poecilia mexicana and Poecilia latipinna JF - BMC Genomics N2 - Background The unisexual Amazon molly (Poecilia formosa) originated from a hybridization between two sexual species, the sailfin molly (Poecilia latipinna) and the Atlantic molly (Poecilia mexicana). The Amazon molly reproduces clonally via sperm-dependent parthenogenesis (gynogenesis), in which the sperm of closely related species triggers embryogenesis of the apomictic oocytes, but typically does not contribute genetic material to the next generation. We compare for the first time the gonadal transcriptome of the Amazon molly to those of both ancestral species, P. mexicana and P. latipinna. Results We sequenced the gonadal transcriptomes of the P. formosa and its parental species P. mexicana and P. latipinna using Illumina RNA-sequencing techniques (paired-end, 100 bp). De novo assembly of about 50 million raw read pairs for each species was performed using Trinity, yielding 106,922 transcripts for P. formosa, 115,175 for P. latipinna, and 133,025 for P. mexicana after eliminating contaminations. On the basis of sequence similarity comparisons to other teleost species and the UniProt databases, functional annotation, and differential expression analysis, we demonstrate the similarity of the transcriptomes among the three species. More than 40% of the transcripts for each species were functionally annotated and about 70% were assigned to orthologous genes of a closely related species. Differential expression analysis between the sexual and unisexual species uncovered 2035 up-regulated and 564 down-regulated genes in P. formosa. This was exemplary validated for six genes by qRT-PCR. Conclusions We identified more than 130 genes related to meiosis and reproduction within the apomictically reproducing P. formosa. Overall expression of these genes seems to be down-regulated in the P. formosa transcriptome compared to both ancestral species (i.e., 106 genes down-regulated, 29 up-regulated). A further 35 meiosis and reproduction related genes were not found in the P. formosa transcriptome, but were only expressed in the sexual species. Our data support the hypothesis of general down-regulation of meiosis-related genes in the apomictic Amazon molly. Furthermore, the obtained dataset and identified gene catalog will serve as a resource for future research on the molecular mechanisms behind the reproductive mode of this unisexual species. KW - Differential gene expression KW - Gynogenesis KW - Hybrid speciation KW - Meiosis KW - Poecilia formosa KW - Poecilia latipinna KW - Poecilia mexicana Y1 - 2018 U6 - https://doi.org/10.1186/s12864-017-4382-2 SN - 1471-2164 VL - 19 IS - 12 SP - 1 EP - 18 PB - BioMed Central CY - London ER - TY - JOUR A1 - Bierbach, David A1 - Schulte, Matthias A1 - Herrmann, Nina A1 - Tobler, Michael A1 - Stadler, Stefan A1 - Jung, Christian T. A1 - Kunkel, Benjamin A1 - Riesch, Rüdiger A1 - Klaus, Sebastian A1 - Ziege, Madlen A1 - Rimber Indy, Jeane A1 - Arias-Rodriguez, Lenin A1 - Plath, Martin T1 - Predator-induced changes of female mating preferences innate and experiential effects JF - BMC evolutionary biology N2 - Background: In many species males face a higher predation risk than females because males display elaborate traits that evolved under sexual selection, which may attract not only females but also predators. Females are, therefore, predicted to avoid such conspicuous males under predation risk. The present study was designed to investigate predator-induced changes of female mating preferences in Atlantic mollies (Poecilia mexicana). Males of this species show a pronounced polymorphism in body size and coloration, and females prefer large, colorful males in the absence of predators. Results: In dichotomous choice tests predator-naive (lab-reared) females altered their initial preference for larger males in the presence of the cichlid Cichlasoma salvini, a natural predator of P. mexicana, and preferred small males instead. This effect was considerably weaker when females were confronted visually with the non-piscivorous cichlid Vieja bifasciata or the introduced non-piscivorous Nile tilapia (Oreochromis niloticus). In contrast, predator experienced (wild-caught) females did not respond to the same extent to the presence of a predator, most likely due to a learned ability to evaluate their predators' motivation to prey. Conclusions: Our study highlights that (a) predatory fish can have a profound influence on the expression of mating preferences of their prey (thus potentially affecting the strength of sexual selection), and females may alter their mate choice behavior strategically to reduce their own exposure to predators. (b) Prey species can evolve visual predator recognition mechanisms and alter their mate choice only when a natural predator is present. (c) Finally, experiential effects can play an important role, and prey species may learn to evaluate the motivational state of their predators. KW - Sexual selection KW - female choice KW - non-independent mate choice KW - predator recognition KW - Poecilia mexicana Y1 - 2011 U6 - https://doi.org/10.1186/1471-2148-11-190 SN - 1471-2148 VL - 11 IS - 3-4 PB - BioMed Central CY - London ER - TY - JOUR A1 - Plath, Martin A1 - Pfenninger, Markus A1 - Lerp, Hannes A1 - Riesch, Rüdiger A1 - Eschenbrenner, Christoph A1 - Slattery, Patrick A. A1 - Bierbach, David A1 - Herrmann, Nina A1 - Schulte, Matthias A1 - Arias-Rodriguez, Lenin A1 - Rimber Indy, Jeane A1 - Passow, Courtney A1 - Tobler, Michael T1 - Genetic differentiation and selection against migrants in evolutionarily replicated extreme environments JF - Evolution N2 - We investigated mechanisms of reproductive isolation in livebearing fishes (genus Poecilia) inhabiting sulfidic and nonsulfidic habitats in three replicate river drainages. Although sulfide spring fish convergently evolved divergent phenotypes, it was unclear if mechanisms of reproductive isolation also evolved convergently. Using microsatellites, we found strongly reduced gene flow between adjacent populations from different habitat types, suggesting that local adaptation to sulfidic habitats repeatedly caused the emergence of reproductive isolation. Reciprocal translocation experiments indicate strong selection against immigrants into sulfidic waters, but also variation among drainages in the strength of selection against immigrants into nonsulfidic waters. Mate choice experiments revealed the evolution of assortative mating preferences in females from nonsulfidic but not from sulfidic habitats. The inferred strength of sexual selection against immigrants (RIs) was negatively correlated with the strength of natural selection (RIm), a pattern that could be attributed to reinforcement, whereby natural selection strengthens behavioral isolation due to reduced hybrid fitness. Overall, reproductive isolation and genetic differentiation appear to be replicated and direct consequences of local adaptation to sulfide spring environments, but the relative contributions of different mechanisms of reproductive isolation vary across these evolutionarily independent replicates, highlighting both convergent and nonconvergent evolutionary trajectories of populations in each drainage. KW - Ecological speciation KW - isolation-by-adaptation KW - local adaptation KW - Poecilia mexicana KW - reinforcement KW - sexual isolation Y1 - 2013 U6 - https://doi.org/10.1111/evo.12133 SN - 0014-3820 VL - 67 IS - 9 SP - 2647 EP - 2661 PB - Wiley-Blackwell CY - Hoboken ER -