Analysis and nonlinear modeling of the mound-building ant Formica lugubris spatial multi-scale dynamic in a larch-tree stand of the southern French Alps

Abstract

International audienceDeterminism in the evolution of a mound-building ant Formica lugubris (Hymenoptera:Formicidae) colony and the impact of environmental perturbations were analyzed using several methods. Variation in dome volume of ant-hills and their activity were followed in a larch forest of the southern French Alps for 8 consecutive years. The dynamic of domes was graphically visualized, and the deterministic component of variations was assessed using linear and nonlinear models (neural networks) in the context of auto-regressive and spatial multi-scale dependences hypothesis. An analysis of residuals was carried out (errors from the best global model) and nonpredictable data were located in perturbed areas (forest clearings and wind-throws). The dynamic of ant colony in the stand was simulated constructing a web of interacting neural net models. Evolution of virtual ant-hills was in accordance with real observed dynamic. The study revealed a very active dynamical system resulting from ants self-organizing in dome construction and confirmed that silvicultural practices can have a negative impact on ant colonies. (c) 2005 Elsevier B.V. All rights reserved