Polymorphism in toxic and colorful prey
Fieldwork experiments & toxic frogs - I studied whether local predators that have already learned a specific colour and pattern of toxic prey could generalise these traits to avoid preying on new toxic morphs. I used as model species toxic and
visually polymorphic Oophaga histrionica frogs. At the Pacific coast forest of Colombia, I fashioned, released and monitored 800 artificial visually polymorphic frog models for three weeks. I found that predators could successfully generalise both colour and pattern to new morphs. I also found that models were attacked more often outside of the original frog distribution, suggesting that predators shape the species spatial distribution (article link). |
Fieldwork experiments & toxic butterflies - I explored the maintenance of several discrete local forms in H. numata by characterising predation pressure in natural populations of this species. Specifically, I tested whether intermediate forms are scarce in natural populations because they match no local pattern, and are thus counter-selected by predators. In a first study, I estimated selection on local and intermediate morphs. I produced more than 5000 artificial prey, imitating the local and intermediate colour patterns of five Peruvian natural communities of H. numata, which I then placed in a tropical forest and monitored during a three-month period. I registered the presence of predator attacks and I found strong predation against intermediate morphs, explaining the maintenance of H. numata discrete morphs (article link).
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Citizen science experiments & toxic butterflies - I studied predators’ response towards intermediate H. numata morphs that are slightly or highly similar to the locally protected forms, in prey communities with different degrees of diversity of colour patterns. Because it is almost impossible to test such a complex question with classical field experiments, I co-produced the videogame "Hungry Birds V.2", including the wide variety of forms used during my field experiment in Peru. I used this videogame in a citizen science experiment where I invited visitors of the Grand Galerie de l’Évolution (Paris) to “prey” on butterflies trying to avoid eating the toxic morphs. This showed the advantage of sharing colours with locally protected morphs, especially in complex communities (article link). I also used this experiment as an outreach activity on the Amazon biodiversity.
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Evolution of chemical defences in Heliconius butterflies - To test the hypothesis that visual polymorphism was related to differences in toxicity in Heliconius species, I compared toxicity between Heliconius species displaying several distinct colour patterns coexisting within each locality (i.e. polymorphic) or exhibiting a single local form (i.e. monomorphic). I collected Heliconius butterflies in northern Peru, and I performed i) predation experiments using birds in Finland (article link) and ii) chemical characterizations (article link). Both studies suggested that the polymorphic species is similarly toxic to locally monomorphic species. Furthermore, using a comparative approach, I identified ecological and life history variations (degree of host plant specialisation and of larval gregariousness) explaining inter-specific differences in toxicity. Currently, I am collaborating with a Colombian team at the University of El Rosario, co-supervising a PhD student investigating the evolutionary mechanisms responsible for the diversity of toxins among Heliconius species along ecological gradients across Colombia.
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