Trained as a population ecologist, his interests span organismal biology and ecology; behavior and population dynamics of consumer-resource interactions; the sensory ecology of mimetism; flow sensing in biotic interactions; locomotion in granular materials and at the air-water interface, physicochemical transport in olfaction and biologically inspired microtechnology. His group is composed of engineers, theoretical and soft-matter physicists, biologists and applied mathematicians working in the field of physical ecology.  A notable feature of his approach is the blending of natural history with both state-of-the-art technology and modeling. He was the director of the Institut de Recherche sur la Biologie de l’Insecte (UMR CNRS) for 7 years. He contributes or did so to many scientific boards, the most notable being BIOKON-The International Biomimetics Association (Berlin) as well as the interdisciplinary committee of the Canada Research Chairs program (Ottawa). He was awarded the ETH medal for a thesis in the University’s top 10%, was nominated junior and later senior member of the IUF (Institut Universitaire Français) and was the Distinguished Invited Professor of the Center for Insect Science at the University of Arizona in Tucson. He did hold the excellency Chair for bio-inspired technologies at the LETI CEA, a research powerhouse on micro-technologies in Grenoble. He was awarded a Humboldt research prize for lifetime achievement and is a corresponding fellow Royal Society of Edinburgh. Prof. Casas also served on the editorial board of a number of ecological, physiological and interdisciplinary journals and is currently co-editor in chief of Current Opinion in Insect Sciences.

Transport and capture of pheromones: a mesoscale approach

Moths are models of chemical communication, performing highly specific, long-range communication via minute amounts of pheromones through a cascade of highly improbable events occurring in succession — transport in the air, capture by an antenna and entry into a sensory pore —this mystery remains intact since Fabre. Critical gaps remain in our knowledge, concerning physicochemical aspects in particular: how can such tiny amounts of pheromones be released and efficiently transported over large distances? When molecules are captured on the antenna, how do they reach the nanometer-wide olfactory pore on the cuticle? What fluid dynamics govern the large diversity of insect antennal forms? How does the environment modify signals? The sensory ecology program I develop with my colleagues, Ph.D. students and post-docs aims to quantify the mechanisms underlying this efficiency, using silkmoths and their feathery antennae as a model. I will focus on two processes — transport and capture —at the meso-scale, between molecules and organisms. Cutting-edge techniques from fluid dynamics (PIV), atmospheric chemistry (FIGAERO-ToF-CIMS) and materials science (AFM) will be used. I will first quantify the partitioning of pheromone transport between the gas and aerosol phases, making use of the finding that pheromones can be efficiently transported not only as single molecules, but also bound to aerosols. I will determine the roles of antennal surface patterning and architecture in capture efficiency, by studying the viscous boundary layers of antennae. If time permists, I will decipher the interfacial processes transporting the molecules to the sensory pores and present our first attempts to integrate our knowledge into an integrated microfluidic biochip performing the first two processes with an unprecedented degree of control.

Keywords: transport processes, physical and chemical ecology, sensory physiology, boundary layer, complex antennae