Infection and transmission of Nosema bombi in Bombus terrestris colonies and its effect on hibernation, mating and colony foundingJozef J.M. van der Steen
PPO Bijen / Applied Plant Research Bee Unit, Wageningen University and Research Centre, Droevendaalsesteeg 1, PO Box 69, 6700 AB Wageningen, The Netherlands
(Received 4 October 2006 - Revised 26 April and 15 November 2007 - Accepted 3 December 2007 - Published online 11 April 2008)
Abstract - The impact of the microsporidium Nosema bombi on Bombus terrestris was studied by recording mating, hibernation success, protein titre in haemolymph, weight change during hibernation, and colony founding of queens that were inoculated with N. bombi in the larval phase. Infection with N. bombi was diagnosed in 36% of B. terrestris queens exposed to N. bombi. Mating and hibernation of queens was not significantly affected by N. bombi infection but colony founding was reduced significantly. Haemolymph protein titre of N. bombi diseased queens was reduced, possibly indicating a disturbance of the metabolism. It was demonstrated that N. bombi infection was transmitted to the successive age cohorts in a colony and to the adults that were already in the colony prior to the introduction of the infection. The study showed a significant negative impact of N. bombi on B. terrestris colony development and indoor rearing.
Key words: Bombus terrestris / Nosema bombi / hibernation / colony founding / mating behaviour / protein / weight / transmission
© INRA, DIB-AGIB, EDP Sciences 2008