PhD Student

Research – Inactivity in ant colonies: function and underlying mechanisms

Given the ecological success and the efficient work organization of insect societies, the high level of inactivity that is commonly observed in ant colonies is quite surprising. Furthermore, setting apart task-targeted activities, insect societies are characterized by some state of arousal that includes seemingly aimless activities (e.g. ants wandering inside the nest). However, the functional value and the mechanisms that regulate ants’ inactivity/arousal are still poorly known and under debate.

In this project, we will see whether some ant colonies are “lazier” than others by measuring their average arousal (Mobile/Immobile ratio) under the same environmental conditions. We will also investigate how colony arousal may change according to its level of starvation, to the size of its workers’ population or to the nest topology.

In addition to a colony-based approach, we will try to understand why differences in arousal may occur at the individual level. To this aim, we will try to relate difference in the activity level of a subset of workers to differences in their response threshold to task-related stimuli, to interactions with nestmates and/or to some spatial specialization inside the nest.

Finally, in order to assess the possible benefits gained from a high arousal, we will compare the foraging efficiency of colonies with different intrinsic activity levels, in the context of food exploitation and competition. We will assess the impact of arousal/inactivity on the recruitment dynamics towards a single food source, on the ability of one colony to discriminate between food sources of different qualities and ultimately on its potential to monopolize food resources in the presence of competitors.

Ultimately, our multi-level approach (individual- and colony-based) will allow to better understand how inactivity/arousal arises in ant colonies and how its tuning can alter the ability of one colony to successfully exploit its environmental resources.

Contact :

USE – CP231

Oscar.Vaes@ulb.ac.be

Plaine Campus, NO Building

bd du Triomphe, B-1050 Bruxelles

Office: 2N5.212

Tel: 02/650.55.30  –  (from abroad +32.2/650.55.30)