HOW DO HONEY-BEES (APIS-MELLIFERA) FUEL THEIR WATER FORAGING FLIGHTS

Water foraging bees in a desert collect water up to 2 km from their co lony, and have consistent crop filling and flight times. They leave th eir colony and arrive at the water source with less than or equal to 1 mg sugar in their crops, which they dilute at the water source by col lecting about 40 mu l of water, In 500 m flights back to the colony, r adioisotope studies show they pass almost no crop contents to their mi dgut. If prevented from entering the colony for 15-36 min, they do pas s about half of their crop contents to their midgut, probably when hem olymph sugar levels become very low. This water is rapidly absorbed fr om the midgut to hemolymph, and then is apparently rapidly excreted to the rectum via the Malpighian tubules and defecated, In this process the bee absorbs and excretes a volume of water at least as great as he r entire hemolymph volume in a relatively short time (less than or equ al to 20 min), The return flights of water collecting bees are normall y fueled from sugar reserves in the bees' bodies, and these reserves l imit water collection to within a few kilometers of the colony. This l imitation probably affects dispersal and density of honey bees in arid areas. Copyright (C) 1996 Elsevier Science Ltd