This is a first. Each time we return from a SEMBA meeting we are excited by some new information but also too exhausted to report anything about it until sufficient time passes that the impulse dies and, oh, it is nearly time for next year’s meeting. A similar phenomenon occurs on shorter timescales with the monthly Ann Arbor Backyard Beekeepers meetings. Yet somehow this time we have managed to write about it not even three weeks later!

We were rather put off by the title of this year’s keynote address, “The Bee Hive as a Honey Factory”, bringing to mind industrialized manipulations to maximize honey crop with disregard of the welfare of the exploited bees. Foolishly we had failed to notice that the speaker was Dr. Thomas Seeley, a Professor in the Department of Neurobiology and Behavior at Cornell University, beekeeper of many years, and author of HoneyBee Democracy. Thus the talk was a fascinating presentation of the ways a colony’s collective decisions arise from communication signals by its individual bees.

Coordination of Nectar Gathering and Receiving

Coordination of the Gathering and Receiving of Nectar (click to enlarge)

First of all, the foragers that return with nectar do not themselves store it in the comb. There are receiver bees in the hive for that job. The forager must find such a receiver and transfer her load before returning to her foraging. Efficient nectar gathering and saving therefore requires a coordination of these work loops so that optimally there are neither receivers standing idle waiting for foragers nor foragers vainly searching for a receiver. The coordinating mechanism is dancing foragers.

Waggle dance

Waggle Dance – the angle from vertical indicates direction of the source from the sun; the duration of the waggle run signifies the distance.

Even non-beekeepers know a bit about the waggle dance as a way foragers tell the hive where nectar can be found. Deciphered by Karl von Frisch in the 1940s, the dancer shakes her booty in a way that encodes the direction, distance, and quality of the nectar source. Sometimes misrepresented as mere announcement of discovery, it is useful to think of this dance as not a notification but rather a recruiting of more foragers.

Frisch was unable to decipher the much less well-known tremble dance, perhaps because this dance seems to lack any structure. Unlike the figure-eight of the waggle dance, the trembling forager seems to wander through the hive at random. One imagines the poor ethologist in the position of someone familiar with the structure of the minuet, waltz, or even the pony observing the free-form terpsichorean paroxysms of modern dance clubs for he eventually concluded that it was simply some meaningless tremens but it is actually a recruiting of more receivers.

The choice of which dance to perform if any at all depends upons how long it took for the forager to find a receiver. If a receiver was found very quickly then the number of active receivers could support more foragers and so she waggle dances to enlist more. If it took a very long time to find a receiver then laden foragers are wandering the hive when they could be out gathering and she tremble dances to enlist more receivers. If the time was of the correct length then delivery and receipt of nectar processes are in balance and she may straightaway return to foraging.

The last relevant signal is the bump and beep. A forager who decides more receivers are needed may notice a previous forager waggling away. Recruiting more foragers would be counterproductive so she tells the other forager to stop by head butting and making a particular kind of beeping noise.

There was much more to the talk, some of which is in HoneyBee Democracy, including what sort of cavities bees prefer for occupancy, how a swarm chooses a home, and descriptions of how all these things were determined by observers and experimenters. It was a splendidly informative way to begin a conference.