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  - Riesch, Rüdiger
A1  - Schlupp, Ingo
A1  - Tobler, Michael
A1  - Plath, Martin
T1  - Reduction of the association preference for conspecifics in cave-dwelling Atlantic mollies, Poecilia mexicana
JF  - Behavioral ecology and sociobiology
N2  - 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.
KW  - cave fish
KW  - Poeciliidae
KW  - Xiphophorus
KW  - shoaling
KW  - species recognition
Y1  - 2006
U6  - https://doi.org/10.1007/s00265-006-0223-z
SN  - 0340-5443
VL  - 60
SP  - 794
EP  - 802
PB  - Springer
CY  - New York
ER  -