“Social immunity and sanitary strategies in ant societies”
Social insects are able to limit interactions with life-threatening organisms such as pathogens.
Ant societies have evolved physical barriers (body cuticle), immune responses or behavioral defenses that make nestmates less vulnerable to diseases. In addition, social mechanisms of prophylaxis and hygiene are collectively achieved within ant societies, including the management of waste or of dead bodies. This so-called social immunity is a central theme of our research group that investigate the mechanisms and functional values of collective sanitary strategies displayed by the ants.
In return for honeydew supply, ants take care of aphids, namely by protecting them against predators and parasitoids. We aim at identifying which life traits of myrmecophilous aphids promote attendance by their ant mutualists.We search for compounds present in aphids, host plants, honeydew or microflora, that are used by ants to detect and discriminate between different aphid partners. Recently, a new project has started about the impact of climate change – i.e. increased temperature and/or higher carbon di-oxyde levels- on this tri-trophic interaction between a plant, an aphid colony and an ant society.
Seed dispersal by ants – also called myrmecochory – characterizes several plant species, over a wide geographical scale. Knowing that plants are competing for the dispersal services provided by ants, we investigate which seed traits (phenology, abundance, ..), which chemical compounds of diaspores or which behavioural traits of the ant workers, can influence the efficiency of the myrmecochory process.
The key-factors that determine the payoff and “loyalty” of each partner will allow to understand why this relationship may shift from a permanent to a transient status depending on the ant-plant pair considered.
“Behavioural rules and Self-organized Patterns”
In the living world, complex collective structures emerge from physico-chemical laws and simple behavioural rules that are coupled with amplifying phenomena. Such rules are generic to many group-living animals (insects, fishes, primates,…) and determine their self-organized collective behavior. We are studying how simple decisions made locally by individuals can give birth to adaptive collective responses as, for example, the coordinated exploitation of the best food resource.
Put in a wider perspective, we are looking at the level of complexity that is required at the individual level to allow the emergence of complex responses at the level of the society. This achieved namely a coupling of experimental and theoretical approaches.
“Division of labour and lazy workers in ant societies”
A major trait of sociality is the integration and coordination of groups of behaviourally specialized workers (coupled or not with caste polymorphism). We try to evaluate the impact of such specialization on the efficiency of collective strategies in foraging, nest defence, brood care or waste management. The observed division of labour is related to the physiology of castes, their behavioural profile, their spatial location and their ability to transfer information to nesmtates. We also question the functional value of lazy ants inside anthills as well as the fitness impact of high inactivity level in ant societies.
“Bioinspiration: hybrid societies of animals and artificial agents”
USE was among the first group to demonstrate experimentally that mixed societies made of insects and robots can co-operate and self-organize themselves into shared shelters. We also investigated how such socially-integrated artificial agents can trigger and control new patterns in group-living insects. Beside, nature has always been an inspiration for humans to develop efficient and sophisticated technologies. While biomimetics has led to several successes, some properties of living systems are still unrivalled by engineered devices (e.g. energetic efficiency or sensorial perception). Therefore,we develop hybrid systems that integrate properties of living organisms with artificial systems by combining insects and robots/or electronic devices that interact with each other.