Sacha Zahnd

I am broadly interested in evolution, with a particular interest in speciation and hybridization.

Hybrid Zone
Hybrid zones are ideal systems to study evolution in real time. The ant species Formica selysi and Formica cinerea hybridize in the Rhône Valley, in the Swiss Alps. In this context, I am interested in disentangling the genetic, behavioural and ecological mechanisms leading to the maintenance of distinct the species.

Maintenance of a social polymorphism
The ant Formica selysi shows two types of social organization. Colonies can be headed either by one queen (monogynous) or by several queens (polygynous). Interestingly, this variation is determined by a genetic variation at a “social chromosome”.  My project aims to investigate how ecological factors contribute to maintain this social polymorphism at micro and macro scale.

2015- present:
PhD supervised by Prof. Michel Chapuisat, University of Lausanne, Switzerland: “Hybridization and maintenance of a social polymorphism in two ant species”

Master in Behavior, Evolution and Conservation, University of Lausanne, Switzerland

Master Thesis: “Characterization and maintenance of an ant hybrid zone”.
Supervisors: Dr Jessica Purcell and Dr Alan Brelsford. Thesis director: Prof Michel Chapuisat

First-step project: “Which demographic factors drive plant reproductive success in an obligate plant-pollinator interaction?”.
Supervisor: Dr. Tomasz Suchan. Thesis director: Prof. Nadir Alvarez

Bachelor in Biology, University of Lausanne, Switzerland.


Office room: 3206.1
Phone: +4121 692 4206
Fax: +4121 692 4165

Member of Chapuisat group

Biophore - CH-1015 Lausanne
Tel. +41 21 692 41 60
Fax +41 21 692 41 65