Evolution of Metabolic rate in Drosophila melanogaster
Energetics or the metabolic rate (MR, energy expenditure in a given time) is a central variable in ecology and evolution, especially in life-history or pace-of-life evolution. Despite its importance, accurate measurement of MR (O2 consumption or CO2 production) at the individual level are rare, especially in small insects. Thanks to the enhancement of respirometry machinery (such as MAVEn from Sable System), we now have access to accurate flow-through individual MR measurement for small ectotherms. During my PhD, I highlighted fundamental differences in how sexes manage their energy budget, via sex differences in the variance and covariance between MR and activity (daily or across period of time) in D. melanogaster. This first step allows me to further explore and reveals sex-specific selection on MR and body mass, as well as substantial genetic variance shared between sexes on MR, indicating for the first time a potential intralocus sexual conflict on MR in Drosophila. In doing so, I made some progress addressing the link between energetics and sexual conflict in small insects.
In addition, the predominant and strong relationship between MR and body mass (at phenotypical and genetic level) can bias our interpretation of the evolution of both traits. In doing so, investigating the evolution of MR will advance how we understand the evolution of the metabolic allometry or condition-dependent (natural or sexual) selection. I am still fascinated by this amazing field. My next step will be to better understand the sex-specific response to selection on MR through the lens of the second theorem of evolution, in addition to uncoupling how MR varies across the different life stages of small insects. |
Quantitative genetics and the evolution of sexual dimorphism
Since Darwin, evolutionary biologists have been fascinated by the sexual dimorphism within anisogamous populations. Sexual dimorphism is theorized to arise from a divergence of the evolutionary interests between females and males, producing sex-specific fitness optimums and sexual antagonistic selection gradients. Although sexually antagonistic selections has been observed in nature, it has been rarely associated with the sexual dimorphism at the phenotypic level within a population, due to the underlying genetic architecture of the traits of interest. Indeed, sexes share most of their autosomal genes, which produce a genetic constraint for sexual dimorphism to evolve, triggering what we call a "intralocus sexual conflict".
I am interested in the sex-specific genetic matrix (Gfm) which captures the genetic architecture of females (Gf) and males (Gm), in addition to the between-sex genetic matrix (B). Using multivariate quantitative genetic approaches reveals that B captures information for shared and unshared genetic variance between sexes, which respectively constrains and enhances the sexual dimorphism evolution. To what extent, traits and sexual dimorphism evolution can be affected by B is still a ongoing research topic. |
Behavioural evolution of insect pest in response to pest management strategies
Integrated Pest Management (IPM) is a central focus of applied biology and agricultural science. Pests feed or damage food production, resulting in severe economic impact for producers. Various strategies -pesticide to predators use- have been implemented, but, despite our efforts, pests remained resilient, and further adapted or developed resistance to those strategies. Evidence of resistance is well known, especially in physiology (detoxification process), and understanding how resistance evolves remains an active topic of research.
Animal behaviour is, to a lesser extent, investigated as a response to the IPM strategies, despite the fact that IPM agents require to be encounter to be active. How behaviour (activity rate, foraging, exploratory behaviour as well as habitat selection ) respond to IPM agents and changes across generations is a key element to understand how pest resistance evolves. Focusing in Quebec insect pest (Lygus lineolaris) might provide answers. This generalist and seasonal insect induces massive damage in fruit and cotton development across North America. My collaboration with UQAM (https://montiglio.wordpress.com) and CRAM (Centre de recherche agroalimentaire de Mirabel) aims: to investigate genetic variance of multivariate dimensional behaviours such as the exploratory behaviour of L.lineolaris, in addition, to understand its change induced by pesticide (cypermethrin) and natural predators (spider or bugs, ambush to hunter) at different levels (population, sexes, temporal and individual). |