Apidologie 36 (2005) 59-70
DOI: 10.1051/apido:2004070

Bumblebee inquilinism in Bombus (Fernaldaepsithyrus) sylvestris (Hymenoptera, Apidae): behavioural and chemical analyses of host-parasite interactions

Stéphanie Dronnet^{a, b}, Xavier Simon^b, Jean-Claude Verhaeghe^{b, c}, Pierre Rasmont^b and Christine Errard<sup>a

a</sup>  Institut de Recherche sur la Biologie de l'Insecte, UMR CNRS 6035, Faculté des Sciences et Techniques, Université François Rabelais, 37200 Tours, France
^b  Laboratoire de Zoologie, Université de Mons-Hainaut, 19 avenue Maistriau, 7000 Mons, Belgium
^c  Laboratoire de l'Environnement, Université Libre de Bruxelles, 81 rue de la Gare, 5670 Treignes, Belgium

(Received 29 January 2004 - Revised 7 May 2004 - Accepted 2 June 2004; Published online: 16 March 2005)

Abstract - The bumblebee Bombus sylvestris is an obligate social inquiline of B. pratorum and nest-invading females are known to integrate themselves into host colonies, usually without any aggression. We investigated whether cuticular compounds could be involved in discrimination processes in common bumblebees, and whether they play a role in the social integration of inquilines in host nests. We tested nestmate recognition in B. terrestris workers, and analysed cuticular chemical profiles of hairs taken from allocolonial individuals. Bumblebees belonging to the same colony shared a common odour. Then, we investigated how B. sylvestris females integrated into colonies of natural and non-natural hosts, B. pratorum and B. terrestris, respectively. Inquiline females apparently succeeded in entering a host colony by expressing non-aggressive behaviours and had no chemical signature; subsequently, acquisition of a chemical signature similar to the host colony might facilitate their integration into the host nest.

Key words: Bombus sylvestris / inquilinism / discrimination process / chemical signature / non-aggressive strategy

Corresponding author: Stéphanie Dronnet dronnet@univ-tours.fr

© INRA, DIB-AGIB, EDP Sciences 2005