Communication of Height by Foraging Honey Bees, Apis mellifera ligustica (Hymenoptera, Apidae)

The Italian honey bee, Apis mellifera ligustica Spin., can determine and communicate the height of a food source as accurately as it can determine the distance, and more accurately than it can estimate the direction. When identical sources of food set out at the same distance and direction from the hive, but at different heights, are discovered by different scouts, distinct groups of foragers form, each recruited to only one of the food sources by the respective scout. The importance of height determination for all winged insects that build nests above the ground, then forage at several levels, has previously been overlooked. Whether such insects are solitary or social, they must be able to determine and compare absolute and relative heights in order to navigate accurately between points at different levels. The height communication mechanism of the honey bee therefore must have emerged from this basic height-sensing system.