Dr Guillaume Chomicki

Glasstone Research Fellow
Extraordinary Junior Research Fellow at the Queen's College

Research area

Mutualism evolution and its impact on species diversity.


Research description

My main research interest revolves around understanding how cooperation among species – or mutualism – evolves, changes or breakdown and how this impacts biodiversity. Cooperation among species has long been a hurdle for Darwinian natural selection. Theory predicts that mutualists frequently turns into parasites and exploit their partner. Shifts to parasitism appear to be rare empirically, and thus whether cheating is an important selective force in mutualism is hotly debated. Moreover, recent data has shown that it least in some systems, freeloaders outside of the mutualisms (phylogenetically unrelated) are frequent.

My work on mutualisms aims to address several questions: (i) When and how mutualism specialise, and what are the implication of mutualism specialisation? (ii) When do mutualisms breakdown? and (iii) How do mutualism vary at a global scale, and how this knowledge help understanding global biodiversity patterns and tailor more efficient conservation strategies?

To address these questions, I use several systems: ant/plant symbioses, notably a group of c. 100 species of Australasian epiphytic Rubiaceae (Hydnophytinae), and I focus all experimental work on a subclade of 9 species that encompass facultative and obligate ant-plants. Secondly, I use all major mutualisms to address macroevolutionary and macroecological questions. This includes ant/plant defense mutualisms, pollination mutualisms, dispersal mutualisms, coral/zooxanthelae symbioses, lichens, mycorrhiza, nitrogen-fixing plants/Rhizobia and more.

My experimental work includes a great deal of field ecology, but also transcriptomics, metabolomics and 3D imaging, while my macroevolutionary work involves essentially database building and phylogenetic comparative methods. 

Recent publications

Coiro M., Chomicki G., Doyle J. Experimental signal dissection and method sensitivity analyses reaffirm the potential of fossils and morphology in the resolution of seed plant phylogeny. Paleobiology (accepted pending revisions).

Pérez-Escobar O.A., Chomicki G., Condamine F.L., de Vos J., Martins A.C., Smidt E.C., Klitgård B., Gerlach G., Heinrichs J. Multiple Geographical Origins of Environmental Sex Determination enhanced the diversification of Darwin’s Favourite Orchids. Scientific Reports 7, 12878.

Chomicki G., Coiro M., Renner S.S. (2017). Evolution and ecology of plant architecture: integrating insights from the fossil record, extant morphology, developmental genetics, and phylogenies. Annals of Botany 120: 855–891.

Pérez-Escobar, O.A., Gottschling, M., Chomicki, G., Condamine, F.L., Klitgaard, B., Pansarin, E. and Gerlach, G. (2017). The improbable journeys of epiphytic plants across the Andes: Historical biogeography of Cycnoches (Catasetinae, Orchidaceae). Scientific Reports 7: 4919.

Sauquet H., von Balthazar M., Magallón S., Doyle J.A., Endress P.K., Bailes E.J., de Morais E.B., Bull-Hereñu K., Carrive L., Chartier M., Chomicki G., Coiro M., Cornette R., El Ottra J.H.L., Epicoco C., Foster C.S.P., Jabbour F., Haevermans A., Haevermans T., Hernández R., Little S.A., Löfstrand S., Luna J.A., Massoni J., Nadot S., Pamperl S., Prieu C., Reyes E., dos Santos P., Schoonderwoerd K.M., Sontag S., Soulebeau A., Städler Y., Tschan G.F., Wing-Sze Leung A., Schönenberger J. (2017). The ancestral flower of angiosperms and its early diversification. Nature Communications 8: 16047.

Pérez O.A., Chomicki G., Condamine F.L., Matzke N.J., Silvestro D., Antonelli A. (2017) Recent origin and geologically-induced diversification of Neotropical orchids in the world’s richest plant biodiversity hotspot. New Phytologist 215: 891–905.

Gutiérrez-Valencia J., Chomicki G. and Renner S.S. (2017). Recurrent breakdowns of mutualisms with ant in the neotropical ant-plant genus Cecropia (Urticaceae). Molecular Phylogenetics and Evolution 111: 196–205.

Chomicki G., Renner S.S. (2017). Partner abundance controls mutualism stability and the pace of morphological change over geologic time. Proceedings of the National Academy of Sciences of the USA 114: 3951-3956.

Chomicki G., Renner S.S. (2017). Ant interactions with their biotic environment. Proceedings of the Royal Society of London B: Biological Sciences 284: 20170013.

Chomicki G, Janda M., Renner S.S. (2017). The assembly of South-East Asian ant gardens: specialization via host broadening. Proceedings of the Royal Society of London B: Biological Sciences 284: 20161759.

Chomicki G., Renner S.S. (2016). Obligate plant farming by a specialized ant. Nature Plants 2: 16181.

Chomicki G., Staedler Y., Schönenberger J., Renner S.S. (2016). Partner choice through concealed floral sugar rewards evolved with the specialization of ant/plant mutualisms. New Phytologist 211: 1358-1370.

Chomicki G., Renner S.S. (2016). Evolutionary relationships and history of the ant-epiphytic genus Squamellaria (Rubiaceae: Psychotrieae) and their taxonomic implications. PLoS ONE 11: e0151317.

Chomicki G., Ward P.S., Renner S.S. (2015). Macroevolutionary assembly of ant/plant symbioses: Pseudomyrmex ants and their ant-housing plants in the Neotropics. Proceedings of the Royal Society of London B: Biological Sciences 282: 20152200.

Chomicki G. and Renner S.S. (2015). Phylogenetics and molecular clocks reveal the repeated evolution of ant-plants after the late Miocene in Africa and the early Miocene in Australasia and the Neotropics. New Phytologist 207(2): 411-424.

Chomicki G., Bidel L.P.R., Ming F., Coiro M., Zhang X., Wang Y., Baissac Y., Jay-Allemand C., Renner S.S. (2015). The velamen protects photosynthetic orchid roots against UV-B damage, and a large dated phylogeny implies multiple gains and losses of this function during the Cenozoic. New Phytologist 205(3): 1330-1341.

Chomicki, G., Renner S.S. (2015). Watermelon origin solved with molecular phylogenetics including Linnaean material: another example of museomics. New Phytologist 205(2): 526-532.