Within colony dynamics of Nosema bombi infections: disease establishment, epidemiology and potential vertical transmissionSamina T. Rutrecht1, 2 and Mark J.F. Brown1
1 Department of Zoology, School of Natural Sciences, Trinity College Dublin, Dublin 2, Ireland
2 Windward Islands Research and Education Foundation, PO Box 7, Grenada, West Indies
Received 20 November 2007 – Revised 27 February 2008 – Accepted 28 March 2008 - Published online 28 October 2008
Abstract - Successful growth and transmission is a prerequisite for a parasite to maintain itself in its host population. Nosema bombi is a ubiquitous and damaging parasite of bumble bees, but little is known about its transmission and epidemiology within bumble bee colonies. The impact of host demography and colony life-cycle on the transmission and reproduction of N. bombi were examined in Bombus lucorum colonies. Parasite success was highest when infecting colonies where larval exposure to the parasite was high. The later individual bees were born in the colony life-cycle, the higher their infection intensity, but after eclosion individual parasite loads did not increase, indicating either host control of the parasite, a balance between internal infection and the production of transmission stages, or a switch in the parasite's growth strategy after eclosion to the production of transmission stages. Finally, trans-ovarial vertical transmission of N. bombi was suggested using molecular probes.
Key words: Nosema bombi / Bombus lucorum / transmission / epidemiology / vertical transmission
© INRA, DIB-AGIB, EDP Sciences 2008