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Volume 32, Number 1, January-February 2001
Page(s) 91 - 103
DOI: 10.1051/apido:2001114

Apidologie 32 (2001) 91-103

Honey bee age-dependent resistance against American foulbrood

Karl Crailsheim and Ulrike Riessberger-Gallé

Institut für Zoologie an der Karl-Franzens Universität Graz, Universitätsplatz 2, 8010 Graz, Austria

(Received 2 August 2000; revised 27 October 2000; accepted 31 October 2000)

American foulbrood is a fatal disease of honeybee larvae. Larvae become infected by swallowing spores of P. larvae larvae that contaminate their food. Adult bees who transfer the spores and have close contact with larvae never become infected. Resistance to this bacterium was investigated in various larval stages and in adults of different ages. Substances inhibiting the growth of P. larvae larvae could be demonstrated in 4 day old larvae and, to a lesser extent, in 1 day old larvae. No such substances could be shown in 6 day old larvae. Extracts of midguts of adult bees generally showed a stronger ability to inhibit growth of the bacteria than did extracts of larvae. It was discovered that the midguts of 8 day old adult bees show a higher growth-inhibiting potential against P. larvae larvae than midguts of freshly emerged adult bees or foragers.

Key words: Apis mellifera / Paenibacillus larvae larvae / age-dependent resistance / honeybee larvae

Correspondence and reprints: Karl Crailsheim

© INRA, EDP Sciences, DIB, AGIB 2001