My research lies at the interface of biology, statistical physics and applied mathematics. I use a collection of empirical, statistical and modelling methods to investigate, from experiments, the mechanisms responsible for the collective behaviours of animals, including insect societies or fish shoals. In particular, I have strong interests in collective motion, i.e. how social groups move together through space in a synchronised and coordinated manner.
The patterns generated by collective motion in fish schools and bird flocks have fascinated humans for centuries, but only in recent decades have advances in modelling and data acquisition allowed collective motion to be investigated with scientific rigour. To research these complex systems is challenging for several reasons, the main one being that different individual rules can lead to the same collective behaviours. It is therefore difficult to infer and disentangle the individual rules from the collective behaviours themselves. The study of these systems with an integrative perspective requires a specific and interdisciplinary framework, especially combining modelling and empirical work at different scales.
- Jul-Oct 2018 Research assistant in Christos Ioannou's group at the University of Bristol, UK. I develop a pilot method encompassing a tracking process derived from optic flow techniques and a machine learning analysis in order to predict traits of large groups of fish as measured on video footage.
- Apr 2018 Lecheval V, et al. Social conformity and propagation of information in collective U-turns of fish schools. Proceedings of the Royal Society B. PDF, supplementary material and data set. Communiqué de presse.
- Mar 2018 Crosato E, Jiang L, Lecheval V, et al. Informative and misinformative interactions in a school of fish. Swarm Intelligence.
- Jan 2018 Calovi D, Litchinko A, Lecheval V, et al. Disentangling and modeling interactions in fish with burst-and-coast swimming reveal distinct alignment and attraction behaviors. PLOS Computational Biology.
- Nov 2017 Jiang L, Giuggioli L, Perna A, Escobedo R, Lecheval V, et al. Identifying influential neighbors in animal flocking. PLOS Computational Biology. Communiqué de presse.
- Oct 2013 Khuong A, Lecheval V, et al. How Do Ants Make Sense of Gravity? A Boltzmann Walker Analysis of Lasius niger Trajectories on Various Inclines. PLOS ONE.
The following data sets can be used to reproduce our results, for new research or for pedagogical purposes, for instance in courses aiming to engage students in scientific inquiry using real data. You can refer to the associated research article for details regarding the empirical set-up or the data treatment.
- Apr 2018 Lecheval V, Jiang L, Tichit P, Sire C, Hemelrijk CK, Theraulaz G (2018) Data from: Social conformity and propagation of information in collective u-turns of fish schools.
This data set contains 2-D trajectories from 68 experiments of single fish and groups of 2, 4, 8 and 10 fish swimming for an hour in a ring-shaped tank filled with 7 cm of water. The corridor was 10 cm wide with a circular outer wall of radius 35 cm and a conic circular inner wall of radius (at the bottom) of 25 cm. Positions of individuals were recorded at 50 frames per second, tracked with idTracker and saved as CSV files. In the ring-shaped set-up, fish schools performed collective U-turns, of interest to monitor the propagation of information. The data set has been analysed in (Jiang L et al., 2017), (Crosato E et al., 2018) and (Lecheval V et al., 2018).
- Oct 2013 Khuong A, Lecheval V, Fournier R, Blanco S, Weitz S, et al. (2013) Data from: How Do Ants Make Sense of Gravity? A Boltzmann Walker Analysis of Lasius niger Trajectories on Various Inclines.
The experiment consisted of single ants walking freely on a white painting canvas, titled with various inclinations (0°, 20°, 30°, 45° and 60°), in a climatic room with a controlled temperature of 26°C and a relative humidity of 50%. For each inclination and each of 3 colonies, 23 ants were collected from their housing container and picked up in turn. The ants were then filmed until they exited from the canvas frame. From the 50 Hz interlaced video recordings, a custom tracking software extracted the position of the ant at each frame with sub-millimeter precision. These tracked points were finally sub-sampled at 25 Hz.
Each archive file contains a series of 69 files, one file per ant. Each file contains the data of a trajectory in a tab-delimited text format with 9 columns, corresponding, respectively, to the inclination index, the colony index, the temperature, the humidity, the recording date, the individual index, the rank of the video frame, the corresponding time in second, and the x and y coordinates in meters. Each file starts with a header row labeling this information.
- Jul 2018 Article La danse organisée des bancs de poissons, published in the popular science magazine La Recherche #537 (July-August 2018). Written by Theraulaz G, Lecheval V and Sire C. To be read freely here in French and here in English.
- Sept 2016 Workshop at the European Researchers’ Night of Toulouse, with a game of virtual reality for children called Panique à Fourmiville!. This game has been designed to explain the building mechanisms of ants, as described by Anaïs Khuong and her colleagues. Children (and adults) had to build the nest of ants before a disaster occurred. Project conducted with Rémi Gouttefarde with whom I developed the game from scratch in R.
- Sept 2016 Dynamics of collective U-turns in fish schools: from empirical data to computational model. Talk at the 2016 Conference on Complex Systems, Amsterdam, The Netherlands.
- Jun 2016 Dynamics of collective U-turns in fish schools: how information propagates within a group. Talk at the Collective Motion 2016 workshop, Uppsala, Sweden.
- Aug 2013 Jost C, Solacroup A, Lecheval V, et al. The influence of gravity on termite displacement. Poster session presented at the International Union for the Study of Social Insects national section meeting, Paris.
- Autumn 2016 64 hours as teaching assistant for the courses Quantitative ecology, Bachelor's programme in Ecology and Statistics, Master's programme in Ecology, Toulouse University, France
- Winter 2015 Invited speaker in the course Advanced Self-organisation of social systems for master's students, Groningen University, The Netherlands
- Autumn 2015 66 hours as teaching assistant for the courses Quantitative ecology, Bachelor's programme in Ecology and Statistics, Master's programme in Ecology, Toulouse University, France
- Autumn 2014 64 hours as teaching assistant for the course Quantitative ecology, Bachelor's programme in Ecology, Toulouse University, France
- 2014-2017 Double PhD degree at the Research Center of Animal Cognition, Toulouse University (France) and the Groningen Institute for Evolutionary Life Sciences, Groningen University (The Netherlands). This PhD project was supervised by Charlotte Hemelrijk (Groningen University, The Netherlands) and Guy Theraulaz (Toulouse University, France). My PhD thesis, entitled Experimental analysis and modelling of the behavioural interactions underlying the coordination of collective motion and the propagation of information in fish schools addressed the questions of coordination of motion and information transfer in groups of fish under internal or external perturbations.
Download the thesis.
Received the second prize of the 2018 National PhD Thesis Award in Complex Systems of the Complex Systems Institute of Paris, France
- 2013-2014 Master programme in Computational Science, Uppsala University, Sweden. Master thesis entitled On collective bandit behaviour supervised by Kristiaan Pelckmans, in Uppsala, Sweden.
- 2011-2013 Master's degree in Ecological Systems Modelling, Toulouse University, France. Master thesis entitled How do the support inclination and the temperature affect the ant motion? supervised by Jacques Gautrais in Toulouse, France.
- 2010-2011 Bachelor of Science in Biology and Environment, Toulouse University, France
- 2008-2010 2-year special undergraduate studies to prepare competitive entrance examinations for admission in engineering schools, École des Métiers de l'Environnement, Rennes, France