Honeybee Democracy how a bunch of tiny-brained bees

achieves a high collective IQ

Tom SeeleyNeurobiology &

BehaviorCornell

University

Estabrook Woods, Massachusetts 1975

Portal, Arizona 1974

Bert! Ed!

Forstenrieder Park, Munich ca. 1952

Martin Lindauer, Karl von Frisch, and students

ML KvF

Martin Lindauer, bee observer extraordinaire

One 16-hour “debate”: 11 sites, 149 scout bees

Seeley and Buhrman (1999) Behav. Ecol. Sociobiol. 45:19-31.

One 16-hour “debate”: 11 sites, 149 scout bees

Bees have a democratic process for choosing a

new home!

How does honeybee democracy work?

1974-1978, 1997-2009(with

collaborators)

Some special tricks of the bees:

1.Decision = reaching a quorum, not a consensus

2.E pluribus unum by means of quorum responses

3.Blending interdependence and independence.

Special Trick #1: Use quorum sensing, not consensus

sensing

Bees build a consensus, but they use it for implementing, not making, their collective

decision

Dynamics on swarm cluster and at nest sites

during swarm decision making

Quorum of scout bees at one site

Consensus among scout bees at swarm

Summary of a swarm’s decision-making process

Decision-making = seeing which option accumulates sufficient

evidence first

0

2

4

6

8

10

12

14

16

1 2 3 4 5 6 7 8 9 10 11 12 13 14

Time

No. of scout bees

Selected nest box

Nonselected nest box

Monkey brain

Bee swarm

Quorum (threshold)

Special Trick # 2: Quickly build a consensus by means

of quorum responses

QR = sharp change in response probability when a threshold

group size is exceeded

probability of

response

Quorum respons

e

Linear respons

e

Sumpter and Pratt (2008) Phil. Trans. R. Soc. B 364:743-753.

No. of individuals in group

Two quorum responses that speed up consensus formation

1. Scouts from site with quorum start producing piping signals on swarm. Effects:

-- non-scouts warm up

-- “losing” scouts give up

2. Scouts from site with quorum start producing stop signals on swarm. Effect:

-- scouts advertising losing sites stop dancing (?)

Active inhibition (!) of bees still advertising non-

chosen sites

Consensus formation is accelerated (evidently) by special inhibition

processes

New!

Special Trick # 3: Blending interdependence

and independenceInterdependence: • bees perform dances, share information

• recruitment creates positive feedback Independence: • bees don’t slavishly copy dances they follow; make own assessment of site and only then dance (or not)

• personal assessment prevents info cascade about inferior site

Variable interdependenc

e,

Full independence

(no mimicking)

High interdependence

(0.8)

Variable independence

(0-1)

List, Elsholtz, and Seeley (2009). Phil. Trans. R. Soc. B 364:755-762.

Swarm Smarts (lessons about good group

decision-making)

• Use open and free debate: a powerful means of aggregating info that is dispersed across a group.

• Use quorum sensing: a means of getting the right balance between speed and accuracy.

• Use quorum responses: a means of eventually achieving consensus, if needed.

• Blend public discussion (interdependence) with private evaluation (independence): a means of avoiding amplifications of poor information

Honeybee Democrac

y

Princeton University Press 2010

Contents

1 Introduction 2 Life in a Honeybee Colony 3 Dream Home for Honeybees 4 Scout Bees’ Debate 5 Agreement on Best Site 6 Building a Consensus 7 Initiating the Move to New Home 8 Steering the Flying Swarm 9 Swarm as Cognitive Entity10 Swarm Smarts

“Second Edition” of my PhD thesis