@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{RieschDuweHerrmannetal.2009,
  author    = {Riesch, R{\"u}diger and Duwe, Virginia and Herrmann, Nina and Padur, Lisa and Ramm, Annemarie and Scharnweber, Inga Kristin and Schulte, Matthias and Schulz-Mirbach, Tanja and Ziege, Madlen and Plath, Martin},
  title     = {Variation along the shy-bold continuum in extremophile fishes (Poecilia mexicana, Poecilia sulphuraria)},
  issn      = {0340-5443},
  doi       = {10.1007/s00265-009-0780-z},
  year      = {2009},
  abstract  = {One potential trade-off that bold individuals face is between increased predation risks and gains in resources. Individuals experiencing high predation and hungry individuals (or individuals with low body condition) are predicted to show increased boldness. We examined one behavioral trait previously reported to be associated with boldness (the time individual fish needed to emerge from shelter) in various populations of mollies (Poecilia spp.). Our study system included several southern Mexican surface streams with high piscine predation and high food availability, sulfidic surface streams with high avian predation, in which the inhabiting fish show reduced body condition, and a sulfidic cave, where predation and body condition are low. Our comparison revealed very short times to emerge from the start box in populations from non-sulfidic streams. In sulfidic habitats (whether surface or cave), it took individual Poecilia mexicana considerably longer to emerge from the start box, and the same difference was also found in an independent comparison between P. mexicana and the closely related, highly sulfide-adapted Poecilia sulphuraria. Fish reared under common garden conditions (in the absence of predators and hydrogen sulfide) showed intermediate boldness scores to the extremes observed in the field. Our data thus indicate that (a) boldness is shaped by environmental conditions/ experiential effects, but is not heritable, (b) predation affects boldness in the predicted direction, but (c) low body condition leads to reduced boldness. Extremophile Poecilia spp. spend most of their time surfacing to survive under sulfidic and hypoxic conditions, which exposes them to increased levels of predations, but the fish forage on the bottom. Hence, in this system, increased boldness does not increase foraging success. We argue that energy limitation favors reducing energetically costly behaviors, and exploring novel environments may be just one of them.},
  language  = {en}
}