What about something internal to the bees as a signal for late winter brood rearing to start? At some point, if the queen does not start laying the colony will be lost from the winter bees dying off. Fat body depletion causing a pheromone to be released that stimulates the queen to lay? Or a pheromone that changes with the age of the bee? David Baker To Bee or Not To Bee *********************************************** The BEE-L mailing list is powered by L-Soft's renowned LISTSERV(R) list management software. For more information, go to: http://www.lsoft.com/LISTSERV-powered.html