"Investigating the factors explaining the rise of termites to dominance" Dr. Thomas Bourguignon

Dr. Thomas Bourguignon
Postdoctoral Research Fellows
The University of Sydney

 

Abstract

Termites are the most abundant terrestrial decomposers, making up to 20% of the animal biomass in tropical and subtropical ecosystems. Yet, the origin of their diversity and abundance, and the factors that helped them to take over decomposition
in tropical and subtropical regions, are unknown. The main goal of my research is to understand how insects, and particularly termites, became the abundant and diversified group they are today. In this seminar, I will present my results on the (1) historical biogeography of termites, and (2) on the evolution of termite defense, both of which having implications in the massive ecological success of termites.

(1) The factors leading to termite dominance across global tropical ecosystems, and the evolutionary timeframe of their diversification, remain poorly understood. I sequenced the full mitochondrial genomes of 500 species to resolve this long pending question. Using phylogenetic trees, I showed that termites appeared some 170 Million years ago, and acquired their modern distribution through dozens of dispersal events since the sharp decrease of global temperature at the end of the Eocene. The rise of termites as major ecosystem engineers was induced by the large-scale extinction episode of the end of the Eocene.

(2) One of the chief reasons of the ecological success of social insects is precisely their sociality. Most members of termite colonies are sterile and gain indirect fitness benefits from a few fertile relatives. I will describe the most extreme altruistic defensive mechanism discovered so far, in old workers of Neocapritermes taracua. N. taracua workers developed a two-component suicidal defensive devise, in which the two components are mixed and react following body rupture. I will present the molecular mechanisms of this intricate defensive device, which I identified using a multi-omics approach.

Biography

I received my PhD in biology from the Free University of Brussels (ULB), Belgium, in May 2010, studying ecology and biodiversity of South American insects, particularly termites. After my PhD, I have been full time postdoctoral researcher at the Hokkaido University, from October 2010 to October 2012, and at the National University of Singapore, from November 2012 to April 2015. While I was in Japan and in Singapore, I continued working on the evolution of termites using next generation sequencing technics. Since May 2015, I am a member of the Sydney Society of Fellows from the University of Sydney, and I joined the Molecular Ecology, Evolution and Phylogenetics (MEEP) laboratory directed by Associate Professor Nathan Lo and Professor Simon Ho.