Some amazing research has been done over several decades in the world of bees that we rarely hear about.
Biophysicists tricked some bees into thinking they had flown 30 times farther than they really flew. The goal was to settle an old debate about how bees judge distance, and the matter was settled by scientists. In other bee news, a group of researchers figured out how to track bees by radar and started watching bees learn to navigate.
The “waggle dance” as we have blogged before, is the way bees share news with their sister bees back at the hive about a fine sweet nectar source they discovered. This dance tells other bees the food’s location, and the duration of the dance conveys the distance the bee travelled. A big zoology debate for decades has been whether bees measure distance visually or estimate it by energy expenditure on a flight.
Biologist Mandyan Srinivasan of the Australian National University in Canberra used a well-known illusion to test how far a bee thinks it has flown. At a given speed, travel seems slower when landmarks are far away—from cruising altitude, a plane doesn't appear to be flying as fast as if it were skimming a few feet off the ground. Srinivasan and his team trained bees that usually fly 2 meters above ground to fly through an 11-cm-wide tunnel with a pattern of complex squares painted on the walls. The closer landmarks should have tricked the bees into thinking they were flying faster—and farther—in the same amount of time—than in their usual distant landscape. The bees were tricked. Back at the hive, after the 6-meter tube excursion, the bees did a waggle dance that lasted as long as it usually would for a 200-meter flight.
This unrelated 4:18-minute video by University of South Australia features Biologist Srinivasan, and shows some of the visuals of the speed and distance experiment:
This was reported by researchers in Science. It was not the first evidence that bees use optical cues to judge distances. Harald Esch, an animal behaviorist at University of Notre Dame in Indiana, showed in 1995 that bees underestimated distance when flying from one tall building to another, like passengers in a plane. Esch agreed that Srinivasan's experiment was the most convincing proof yet. "This settles the issue of optical measurement of distance in honeybees," Esch said.
Another lengthy debate in bee research is how well bees learn directions to a food source from the waggle dances they do for each other. To answer the question, an individual bee must be watched after it sees a dance, but researchers can only track bees visually for about 10 meters.
A group of researchers reported they could track individual bees for up to 700 meters by using an adapted form of radar that involves antennas being attached to bees. Entomologist Elizabeth Capaldi of the University of Illinois, Urbana-Champaign, said the radar maps show that bees do not know how to "make a beeline" right away. They must first take some training flights, and progressively fly longer distances at faster speeds. This was reported by researchers in Nature.
Zoologist Fred Dyer of Michigan State University, East Lansing, said it all makes intuitive sense. Some issues were as yet to be solved—like making the long antennas short enough so bees could enter the hive. Dyer and Esch expected the radar technique to finally help decipher bee communications.