Are more toxic prey better protected?

This is the question addressed in Mathieu Chouteau’s paper, just published in Animal Behaviour (vol 153:49-59).

How do bird predators consider the natural range of variation in toxin load among butterfly species in a community? Mathieu asked chicks what they thought of the chemically-defended butterflies composing the mimicry communities of Eastern Peru. He measured how fast they would learn to avoid butterfly-flavoured food crumbs, as opposed to tasty crumbs. Surprisingly, Mathieu found that only a few butterfly species with low loxin content can improve their aversiveness to chicks. Most well-defended prey elicited similar learning rates, irrespective of the wide variation in their concentration in cyanogenic or other distasteful compounds.

Then, why should butterflies invest in high toxicity ? Some can be really nasty ! If natural predators such as jacamars or flycatchers learn like chicks, the benefits to butterflies in loading themselves with toxins may lie elsewhere than in the education of predators. Perhaps in accessing competition-free hostpants, or in making better pheromones, or in elicting immediate taste-rejection ?

Another important consequence is that differences in toxicty among mimetic butterflies may not represent a major determinant of their roles as mimics vs. models. On the contrary, if all toxic species are considered equally aversive by predators, their roles in predator education should be determined primarily by their relative abundances. Fritz Muller was right again!

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Two positions available – Apply now

Two positions are open in my group, to work on the ecology and evolutionary genomics of mimicry supergenes in Heliconius butterflies.

1- A 3-year PhD studentship on the ecology of inversions and balancing selection. The project aims at deciphering the evolution of a complex of chromosomal inversions forming a supergene in H. numata. The PhD student will study the selective factors (e.g. viability trade-offs, deleterious variations, etc.) and the mating signals (visual, olfactory) contributing to the maintenance of inversion polymorphism.
Full announcement :
Deadline for applications : 12/06/2019.

2- A 2-year postdoc position on the population genomics of supergenes and inversions. The project aims at improving our understanding of how inversions have established and spread in populations and through the Amazonian range, and how inversion polymorphism is associated with changes in the connectivity and demography of populations, likely to affect ecological and evolutionary trajectories of polymorphic populations.
Full announcement :
Deadline for applications : 20/06/2019

Please do circulate those ads around your labs and do not hesitate to contact me for more details on the project or the application procedure.

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Alien inversion

May 2018: Congratulations to Paul Jay, Annabel Whibley, Angeles de Cara, Lise Frézal and Reuben Nowell (!) for their paper showing that the supergene was formed via the introgression of an inversion. Supergene alleles evolved their differences and coadaptation in different species. That’s now in Current Biology!

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Polymorphism not maintained by mimicry

July 2017: Congratulations to Mathieu Chouteau for his paper in PNAS, showing how H. numata mate disassortatively with respect to mimetic wing pattern. Polymorphism is not maintained by mimicry, really!

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