@article{RieschSchluppTobleretal.2006, author = {Riesch, R{\"u}diger and Schlupp, Ingo and Tobler, Michael and Plath, Martin}, title = {Reduction of the association preference for conspecifics in cave-dwelling Atlantic mollies, Poecilia mexicana}, series = {Behavioral ecology and sociobiology}, volume = {60}, journal = {Behavioral ecology and sociobiology}, publisher = {Springer}, address = {New York}, issn = {0340-5443}, doi = {10.1007/s00265-006-0223-z}, pages = {794 -- 802}, year = {2006}, abstract = {Cave animals are widely recognised as model organisms to study regressive evolutionary processes like the reduction of eyes. In this paper, we report on the regressive evolution of species discrimination in the cave molly, Poecilia mexicana, which, unlike other cave fishes, still has functional eyes. This allowed us to examine the response to both visual and non-visual cues involved in species discrimination. When surface-dwelling females were given a chance to associate with either a conspecific or a swordtail (Xiphophorus hellerii) female, they strongly preferred the conspecific female both when multiple cues and when solely visual cues were available to the female. No association preference was observed when only non-visual cues were provided. In contrast, cave-dwelling females showed no preference under all testing conditions, suggesting that species recognition mechanisms have been reduced. We discuss the role of species discrimination in relation to habitat differences.}, language = {en} } @article{ToblerSchluppHeubeletal.2006, author = {Tobler, Michael and Schlupp, Ingo and Heubel, Katja U. and Riesch, Rudiger and Garcia de Leon, Francisco J. and Giere, Olav and Plath, Martin}, title = {Life on the edge: hydrogen sulfide and the fish communities of a Mexican cave and surrounding waters}, series = {Extremophiles : life under extreme conditions}, volume = {10}, journal = {Extremophiles : life under extreme conditions}, publisher = {Springer}, address = {Tokyo}, issn = {1431-0651}, doi = {10.1007/s00792-006-0531-2}, pages = {577 -- 585}, year = {2006}, abstract = {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.}, language = {en} } @article{RieschToblerPlathetal.2009, author = {Riesch, R{\"u}diger and Tobler, Michael and Plath, Martin and Schlupp, Ingo}, title = {Offspring number in a livebearing fish (Poecilia mexicana, Poeciliidae) : reduced fecundity and reduced plasticity in a population of cave mollies}, issn = {0378-1909}, doi = {10.1007/s10641-008-9392-0}, year = {2009}, abstract = {Life history traits within species often vary among different habitats. We measured female fecundity in mollies (Poecilia mexicana) from a H2S-rich cave and from a neighbouring surface habitat, as well as in laboratory-reared individuals of both populations raised in either light or continuous darkness. Compared to conspecifics from surface habitats, cave-dwelling P. mexicana had reduced fecundity (adjusted for size) in the field. In the laboratory, the fecundity of surface mollies was higher in light than in darkness, whereas fecundity in the cave mollies was almost unaffected by the ambient light conditions. Our results suggest a heritable component to the reduction in fecundity in female cave mollies. Moreover, the reduced plasticity in fecundity of cave mollies in response to light conditions might be an example of genetic assimilation or channelling of a life history trait in a population invading a new environment.}, language = {en} } @article{McCoySyskaPlathetal.2011, author = {McCoy, Ellen and Syska, Norbert and Plath, Martin and Schlupp, Ingo and Riesch, R{\"u}diger}, title = {Mustached males in a tropical poeciliid fish - emerging female preference selects for a novel male trait}, series = {Behavioral ecology and sociobiology}, volume = {65}, journal = {Behavioral ecology and sociobiology}, number = {7}, publisher = {Springer}, address = {New York}, issn = {0340-5443}, doi = {10.1007/s00265-011-1154-x}, pages = {1437 -- 1445}, year = {2011}, abstract = {One possible mechanism for the (co-)evolution of seemingly novel male traits and female preferences for them is that males exploit pre-existing female biases, and livebearing fishes (Poeciliidae) have been at the forefront of this research for almost two decades. Here, using 13 poeciliid species from four different genera, we tested whether mustache-like rostral filaments found in males of some Mexican molly (Poecilia sphenops) populations could have evolved due to exploitation of a pre-existing female bias. While Mexican mollies were the only species with a significant female association preference for mustached males, we also did not find any species exhibiting significant aversion for mustached males; rather, variance in female preference scores was large throughout. For example, more than 25\% of females spent twice as much time with the mustached male compared to the non-mustached male in most species, but even 31\% of Mexican molly females spent more time near the non-mustached male. Hence, a comparison of the strength of preference was inconclusive. We discuss the possibility that the female preference of P. sphenops for mustached males could be due to a female pre-existing bias (sensu lato), even if population means were not significant for species other than P. sphenops. This highlights the importance of distinguishing between population means and individual preferences when interpreting mate choice, and thus, adds depth to the concept of mating preferences as a motor for evolutionary change.}, language = {en} }