Greetings I have long wondered if rapid collapse of honey bee colonies infested by varroa, and the so-called "colony collapse disorder" might not be caused by a mass exodus of bees in an attempt to rid the colony of parasites. This could in fact be a last ditch effort to save the queen and enough bees to carry on. Obviously, it fails when carried out in the fall, in northern climates but could have evolved in tropical bees where a small nucleus could in fact regenerate the colony. This idea was put into print in the latest American Bee Journal on page 104. See "Dying outside for the good of the colony" by Jasna Kralj of Ljubljana, Slovenia. She and Stefan Fuchs wrote about this last year in Apidologie (how did I miss that article?) Excerpt: We suggest there could be a colony benefit from not returning to the colony by the removal of the pathogens. Smith-Trail discussed the possibility for an adaptive sacrifice of one's life for the benefit of kin in response to parasites ("suicide hypothesis"), and some examples have since been described in butterflies and aphids. In social insects, bumble bees infested by conopid flies respond by behavioural changes costly to the individual but beneficial to the colony, but up to now there are no clear examples that parasitized individuals might leave the colonies in order to remove pathogens. Parasitic Varroa destructor mites influence flight duration and homing ability of infested Apis mellifera foragers Jasna Kralj, Stefan Fuchs Apidologie 37 (2006) 577–587 ****************************************************** * Full guidelines for BEE-L posting are at: * * http://www.honeybeeworld.com/bee-l/guidelines.htm * ******************************************************