Mathieu Joron

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I have been working with Heliconius butterflies since 1996, when I started my PhD with Jim Mallet in University College London and Isabelle Olivieri in Montpellier. I was initially interested in ecological factors explaining the maintenance of polymorphisms and diversity in mimicry and warning colour. I went to  Eastern Peru for fieldwork, where I got amazed at the diversity of mimicry systems, and at the spectacular mimetic convergence between unrelated kinds of butterflies and other insects. I worked on theoretical models with Yoh Iwasa, but most of my work was on the ecological maintenance of polymorphism in Heliconius numata, an exceptionnally polymorphic species where many morphs are found in the same localities, each one mimicking a distinct set of mimetic species (or mimicry ring) dominated by Ithomiine butterflies. I also spent a long time producing crosses in Heliconius numata to examine Keith Brown and Woody Benson’s 1974 “supergene” hypothesis; indeed I could confirm that polymorphism was controlled by a single locus with many alleles, all lined up in a hierarchical series of dominance relationships. This could explain the maintenance of distinct mimetic forms without the blending effects of recombination that is observed in wing-pattern hybrid zones of other Heliconius butterflies.

After a postdoc with Paul Brakefield in Leiden (NL) where I discovered that inbred male Bicyclus anynana are not good at getting females (except perhaps in small cages!), I started to work more closely on the supergene architecture of Heliconius numata. After another year of crossing butterflies and producing mapping families in Peru, and in collaboration with Jim Mallet and Chris Jiggins, we carried out linkage mapping and discovered the positional homologies of wing-patterning loci in multiple Heliconius species, and the existence of a “toolkit” of wing-patterning genes reused throughout this butterfly radiation. Notably, the supergene P in Heliconius numata was proved to be the homologue of a cluster of loci known in other species. Since then, we have been refining our understanding of thopse regions in H. numata and other species, and discovered that the supergene was maintained by a complex series of inversions which lock together distinct adaptive combinations of genes producing near-perefect mimicry of distinct patterns.

I was appointed at the CNRS as a permanent researcher at the Natural History Museum in Paris, but have since moved to the CEFE, a major ecology lab in Montpellier, South of France. My group works on several aspects of adaptation in Heliconius (wing pattern ecological genetics, genomics of adaptation, chromosomal inversions..), especially in the clade of Heliconius numata and related species (the so-called “silvaniforms”). We try to combine and integrate multiple approaches, from population genomics to transcriptomics, and from behavioural ecology to morphometrics, which together improve our understanding of the ecological, genetic, and morphological changes associated with adaptation and speciation.

For more details on our work please see our lab webpage.

Recent publications