Unité d’Ecologie Sociale (USE)
ULB CP 231
Campus de la Plaine
bd du Triomphe, B-1050 Bruxelles
Tel: 02.650.55.30 (from abroad +32.2.650.55.30)
Fax: 02.650.59.87 (from abroad +32.2.650.59.87)
Social immunity and sanitary risks management within the ant nest : behavioral, spatial and organizational adaptations of the species Myrmica rubra face to an entomopathogen.
For several years, sociobiology is interested in the impact of disease on the colonies of eusocial insects. Indeed, although a high level of sociality has advantages in many respects, such as the emergence of collective defense, the division of labor, or increased ability to modify the environment (in particular to ensure homeostasis of living’s conditions) ; this system also involves the emergence of new constraints. One of the strongest is probably the health risk of transmission of pathogens due to the physical and genetic proximity of eusocials individuals who live in high density in the confined environment of the nest or hive. These insects have therefore developed defense mechanisms to protect themselves and limit their exposure to pathogens.
My research project aims to better understand the organizational changes taking place when an ant colony is facing an invading pathogen. When studying the relationship between on the one hand a pathogen (here Metarhizium anisopliae) and on the other hand a host (here Myrmica rubra), it is important to know the process of invasion and spread of the pathogen as well as the means used by insect colonies, both individually and collectively, to limit and control the infection. My research will focus on the second part, and thus immunity organizational colonies. To do this, we will investigate several ways in M. rubra to limit the factors favoring transmission of a pathogen between congeners. Firstly, we will observe how behavioral and spatial changes of infected and uninfected individuals can limit the frequency and type of interactions between workers, critical factors in the contamination of healthy individuals. The corpses, and more generally organic waste, are often responsible of infection, these having high pathogenicity. We will study how colonies managed these organic waste, especially in terms of their demographics, and how this management can limit an invading pathogen. But the characteristics of the nest, as the structure of the network, are also a key factor in the spread of infection. We therefore seek to determine the influence of the compartmentalization of the nest and topological modifications made actively by the workers on their survival when a source of infection is detected within it.