Unit of Social Ecology (USE)
ULB CP 231
Campus de la Plaine
Bd. du Triomphe, B-1050 Bruxelles
Tel: 02.650.55.28 (from abroad +32.2.650.55.28)
Fax: 02.650.59.87 (from abroad +32.2.650.59.87)
Impact of spatiotemporal availability and attractiveness of myrmecochorus seeds on the dispersal activity of Myrmica rubra ants.
Seed dispersal by ants (called myrmecochory) is an insect-plant interaction in which plants developed a number of morphological (presence of an attractive appendage called elaiosome) and phenological features (pattern of seed release) that are species-specific and that are involved in the attraction of the dispersal vector. Since plants are competing for the ant’s dispersal services, those plant features are important for the establishment and the maintenance of this diffuse mutualism. My researches focus on several phenological traits, such as spatial and temporal seed availability or the chemical attractiveness of elaiosomes, shown by Chelidonium magus to arouse the interest from workers of Myrmica rubra ant species. Through experimental studies carried out both in the field and in controlled laboratory conditions, we will relate those phenological traits with the dynamic of seed harvesting, seed rejection and elaiosome consumption by Myrmica rubra ant colonies. I also try to understand how myrmecochory evolves when ants are faced several times with the same seed species – in this case C. magus seeds but also Viola odorata seeds, the latter being known to induce a progressive extinction of ant’s response. Such a comparative study will allow to determine the mechanisms underlying the temporal adjustment of foraging following a prolonged exposure of ants to the same food source, among which satiation, neophilia or associative Learning of nutrient income or toxicity will be investigated. Finally, the identification of actors is also important (larvae, foragers or nurses) involved in such foraging adjustment. Such a study of spatial and temporal features of seed phenology is fundamental to understand the efficiency as well as the evolution of the mutualistic relationship between myrmecochorus plants and ants.