title: Differences in chemosensory response between eyed and eyeless Astyanax mexicanus of the Rio Subterráneo cave.
abstract: BACKGROUND
  In blind cave-dwelling populations of Astyanax mexicanus, several morphological and behavioral shifts occurred during evolution in caves characterized by total and permanent darkness. Previous studies have shown that sensory systems such as the lateral line (mechanosensory) and taste buds (chemosensory) are modified in cavefish. It has long been hypothesized that another chemosensory modality, the olfactory system, might have evolved as well to provide an additional mechanism for food-searching in troglomorphic Astyanax populations.
  
  
  RESULTS
  During a March 2013 cave expedition to the Sierra de El Abra region of San Luís Potosi, Mexico, we tested chemosensory capabilities of the Astyanax mexicanus of the Rio Subterráneo cave. This cave hosts a hybrid population presenting a wide range of troglomorphic and epigean mixed phenotypes. During a behavioral test performed in situ in the cave, a striking correlation was observed between the absence of eyes and an increased attraction to food extract. In addition, eyeless troglomorphic fish possessed significantly larger naris size than their eyed, nontroglomorphic counterparts.
  
  
  CONCLUSIONS
  Our findings suggest that chemosensory capabilities might have evolved in cave-dwelling Astyanax mexicanus and that modulation of naris size might at least partially underlie this likely adaptive change.
authors.affiliation: Equipe Développement Evolution du Cerveau Antérieur, UPR3294 N&D, CNRS, Institut Alfred Fessard, Gif-sur-Yvette F-91198, France.
authors.forename: Jonathan
authors.initials: J
authors.lastname: Bibliowicz
authors.affiliation: Equipe Développement Evolution du Cerveau Antérieur, UPR3294 N&D, CNRS, Institut Alfred Fessard, Gif-sur-Yvette F-91198, France.
authors.forename: Alexandre
authors.initials: A
authors.lastname: Alié
authors.affiliation: School of Science, Marist College, Poughkeepsie, NY, USA.
authors.forename: Luis
authors.initials: L
authors.lastname: Espinasa
authors.affiliation: Department of Biology, University of Maryland, College Park, MD, USA.
authors.forename: Masato
authors.initials: M
authors.lastname: Yoshizawa
authors.affiliation: Equipe Développement Evolution du Cerveau Antérieur, UPR3294 N&D, CNRS, Institut Alfred Fessard, Gif-sur-Yvette F-91198, France.
authors.forename: Maryline
authors.initials: M
authors.lastname: Blin
authors.affiliation: Equipe Développement Evolution du Cerveau Antérieur, UPR3294 N&D, CNRS, Institut Alfred Fessard, Gif-sur-Yvette F-91198, France.
authors.forename: Hélène
authors.initials: H
authors.lastname: Hinaux
authors.affiliation: Equipe Développement Evolution du Cerveau Antérieur, UPR3294 N&D, CNRS, Institut Alfred Fessard, Gif-sur-Yvette F-91198, France.
authors.forename: Laurent
authors.initials: L
authors.lastname: Legendre
authors.affiliation: Equipe Développement Evolution du Cerveau Antérieur, UPR3294 N&D, CNRS, Institut Alfred Fessard, Gif-sur-Yvette F-91198, France.
authors.forename: Stéphane
authors.initials: S
authors.lastname: Père
authors.affiliation: Equipe Développement Evolution du Cerveau Antérieur, UPR3294 N&D, CNRS, Institut Alfred Fessard, Gif-sur-Yvette F-91198, France.
authors.forename: Sylvie
authors.initials: S
authors.lastname: Rétaux