HONEYBEES ARE THE MOST AMAZING INSECTS

by Whit Gibbons

October 2, 2005

Remember honeybees, the little brown and yellow creatures that used to visit flowers, make honey, and sting you when you stepped on one barefooted? Actually, honeybees are still around, but in low supply. A major reason for their disappearance is because of an introduced mite first described in Java a century ago. Varroa mites were discovered on honeybees in Florida and Wisconsin in the mid-1980s. Since then, they have caused noticeable declines in honeybees throughout the country.

Nonetheless, more is known scientifically about honeybees than almost any other insect. Part of our fascination with these amazing little creatures comes from the excellent research of behavioral scientists and geneticists. Especially intriguing are the colonial attributes of honeybees, in which the workers, all females, will defend their colony to the death, tend the developing young, and even regulate the temperature of the hive. Because of their honey-making abilities, honeybees have been introduced on every warm continent.

Honeybees have been the focus of behavioral studies for decades, and despite the declining numbers of honeybees (let's hope it is only temporary), entomologists and behavioral ecologists continue to study them. During the past year, research provided an explanation for how honeybees navigate from the hive to a food source.

Many researchers have been especially fascinated by the implications of the "waggle dance" performed within the hive, in which a returning bee dances around on the vertical surface of the honeycomb to tell other bees where a newly discovered food source is. When "the language of the bees" was first described by Karl von Frisch in the early 1900s, other scientists probably thought he was delusional. By the time he was awarded a Nobel Prize in 1973, everyone knew that bees could communicate with each other quite well.

The function originally ascribed to the dance of the bees was to allow the returning bee to convey to other bees (the recruits) the direction and distance of the new food source from the hive. However, some investigators challenged this interpretation, proposing that the recruits attending the dance were not decoding it at all, but were merely picking up odors of the food source that were still clinging to the dancing bee. According to this interpretation, the recruits then flew out of the hive and searched for the food by tracking down the source of these food odors borne on the wind. So, the question of how the bees actually used the dance information was still in dispute.

A group of scientists led by J. R. Riley and A. D. Smith of Rothamsted Research in England tested the effectiveness of the waggle dance as a navigational guide by placing tiny harmonic transponders on recruits as they left the hive in search of the designated food source. To take the natural variability out of the experiment, they set up an unscented artificial feeder more than one-tenth of a mile east of the hive. In addition to releasing recruits at the hive, the investigators moved some recruits the same distance to the southwest of the hive before release. Signals from the transponders were detected by radar so that the actual flight paths of the bees could be mapped.

Of the recruits released at the hive, most flew unerringly to the immediate vicinity of the feeder, but only a small proportion actually located it. Most searched but presumably because no scents or visual cues were available were unable to find the feeder. These results provided very strong support for the hypothesis that the waggle dance communicates distance and direction, but that the target is finally located by other cues, such as smell, that would be present in natural food sources. Even stronger support for the hypothesis was provided by the flight paths of the recruits released from the nonhive locations. The radar tracks showed that these followed the same compass direction and went the same distance as those released at the hive, ending up in completely the wrong place, too far west and too far south.

The honeybee findings are indeed captivating. But think about the scientific complexity and technological advancements involved in conducting such a study. The scientists are as impressive as the bees.



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