Evolution of nervous system and behaviour in blind cavefish Astyanax mexicanus
type: Dataset
description: Astyanax mexicanus is a teleost fish model used for evolution studies. Among the same species, there are several populations of sighted surface fish (SF) that live in Mexican rivers and at least twenty nine populations of blind cavefish (CF) that live in perpetual darkness. Several of these cave populations are independently-evolved, and they derived from surface fish-like ancestors. CF have lost their eyes and their pigmentation, and they have also evolved a number of behavioral traits. Most CF populations have lost the aggressive behavior that is a trademark of their SF counterparts. Here we characterized behavioural differences between SF and CF and we investigated the modifications of neural networks responsible for the loss of aggressiveness in cavefish. We first characterized aggressive behavior in Astyanax. Using an “intruder assay”, we found that SF not only attack ten times more during a one hour period, but also show a significantly different pattern in the temporal distribution of their attacks: while two CF attack mostly during the first minutes, SF attack more and more frequently as time goes by during the test. Then we demonstrated that the loss of aggressiveness in CF is not due to their blind phenotype, and using hybrids and independently-evolved populations of CF we could suggest that aggressive behavior in SF is genetically-encoded. After pharmacological experiments using compounds modulating serotonin levels or using SF and CF receiving different food regimes, we hypothesized that the loss of aggressiveness of CF may correspond to an adaptation to cave life, as they spend most of their time looking for food. On the other hand, the aggressiveness of SF is closely connected to the hierarchy within the school, dominance itself being mainly due to the levels of serotonin in the raphe. Thus, serotonin levels are inversely correlated with agonistic behavior. Neuroanatomical analyses on SF and CF brains showed an identical organization of their serotonin…
landing page: https://theses.hal.science/tel-00978774
identifier: NNT: 2013PA11T014
keyword: aggressiveness
keyword: agressivite
keyword: aminergic-system
keyword: astyanax
keyword: behaviour
keyword: catecholamine
keyword: cavefish
keyword: comportement
keyword: foraging
keyword: infoeu-reposemanticsdoctoralthesis
keyword: monoamine-oxidase
keyword: monoamine-oxydase
keyword: nervous-system
keyword: poisson-cavernicole
keyword: recherche-de-nourriture
keyword: sdvsalife-sciences-q-bioagricultural-sciences
keyword: serotonin
keyword: serotonine
keyword: systeme-aminergique
keyword: systeme-nerveux
keyword: theses
keyword: transgenese
keyword: transgenesis
issued: 2026-05-05T14:45:12.703227
modified: 2026-05-05T14:45:12.703232
language: fr
contact point: Organization
  fn: CCSD

test_moissonnage_selune
type: Agent

Evolution of nervous system and behaviour in blind cavefish Astyanax mexicanus
type: Distribution
format: HTML
access URL: https://theses.hal.science/tel-00978774
issued: 2026-05-05T14:45:12.709657
modified: 2026-05-05T14:45:12.677667