they speak to us. The different populations, geographically structured, have very distinct colourings (all the photos illustrating the article represent Dendrobates tinctorius . Thanks to Cyril Gaertner for his patience), with an identical message to potential predators: they are toxic! Their colour is optimised for the pre- dator community. The brighter the colour, the more toxic the frog, and the less fearful it is. We are currently investigating what might drive the degree of toxicity. It would seem that the alkaloids contained in its skin are acquired during feeding, composed of microinverte- brates that vary from one place to another: it would be dependent on them to compose its chemical defence cocktail. Evolution means that everything is measured out: a less toxic animal must be less colourful, more discreet in the eyes of predators. What also surprises us is the ability of different populations to maintain their distinct colou- ring in terrestrial environments (this is much
more common in island environments). Possible interbreeding should standardise populations, but here we are in a way faced with the basis of ecological speciation: at what point do the barriers that prevent reproduc- tion come into place, at what point do popula- tions take distinct evolutionary paths to beco- me fully-fledged species? This is one of the rea- sons why we hybridize between populations. By studying Dendrobates tinctorius , we hope to learn more about the appearance of new spe- cies in the Amazon. Behaviour, genetics asso- ciated with coloration patterns, we are stu- dying everything that helps to answer the question: why don't we observe hybrids bet- ween populations in the wild? Our platform allows us to generate these hybrids to try to understand. We have been able to observe that certain populations refuse to reproduce with partners of different colours. In some cases we have been able to show that the hybrid offspring have less chance of survi- val (high mortality in the larval stage), and that they have difficulty reproducing after- wards. We are very lucky to be able to maintain this wild population for scientific purposes.
~C L A S S & R E L A X L I F E S T Y L E M A G A Z I N E - 2023 ~
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