Conference Paper
Olfactory behavior of different wild Astyanax mexicanus populations
Blin, M., Fumey, J., Père, S., Pierre, C., Torres-Paz, J., Simon, V., Espinasa, L. Legendre, L., Casane, D. and Rétaux, S.
Record Number:
4280
Year:
2019
Journal:
AIM 2019
Pages:
32
Abstract:
We study the evolution of brain and behaviors in the micro-evolution fish model, Astyanax
mexicanus. About 30 blind CF populations are described today, distributed in caves belonging to
three mountain ranges in the state of San Luis Potosi and Tamaulipas. During their rapid
evolution, in less than 20,000 years in total and permanent darkness, CF have undergone
numerous morphological and behavioral changes. In particular, CF originating from the Pachón
cave show a striking evolution of their olfactory system as compared to surface fish, probably to
compensate for the loss of vision in the dark. Indeed, under controlled laboratory conditions,
Pachón CF have an odor discrimination threshold "100,000 times better" than that of SF (Hinaux
et al., Development 2016; Blin et al., Developmental Biology 2018).
The local conditions are variable among the 30 Astyanax caves, including in terms of the level of
trophic support (carbon content, presence of arthropods on which fish can feed), the presence or
not of large bat colonies (and associated guano), or the introgression of surface fish into caves at
the rainy season (gene flow). In order to investigate whether the olfactory skills we have
discovered in the Pachón CF in the lab is a shared trait among all cave populations, or whether
they may depend on the local environmental conditions in which each population has evolved, we
have organized field work to test the olfactory capacities and behavior of CF in 5 different caves,
in situ in their natural environment (Pachón, Sabinos, Tinaja, Chica, Subterraneo). To this end,
we have developed a transportable olfactory behavior setup adapted to the harsh conditions of
the natural environment, and tested behavioral responses of wild CF populations to amino acids
and chondroitin sulfate odorant molecules. The results show that globally, the olfactory capacities
of wild CF are better than those of SF. The exceptional olfaction of Pachón CF in the lab is also
found in the wild. In other caves, responses are variable. For example, in Tinaja and Chica caves
which are located in the same mountain range as Pachón, responses are weak, but in the
Subterraneo cave which is located in a different mountain range, good olfactory skills were
recorded. Combining these data and what we know about the specific environment in these
different caves (energy supply, growth conditions) should enlarge our integrated vision of the
evolution and adaptation of the sensory systems of CF Astyanax mexicanus.
Work supported by IDEEV, CNRS, ANR and an Equipe FRM grant.
Times Cited:
1
Conference Name:
Astyanax Interrnational Meeting
Relevent Species: