Appointment Keeping in Honey Appointment Keeping in Honey Bees: Molecular ClocksBees: Molecular Clocks

N. L. NaegerN. L. NaegerUniversity of Illinois, Urbana-ChampaignUniversity of Illinois, Urbana-Champaign

BeeSpace Workshop, 21 May 2009

What do bees What do bees have to do with have to do with

time and time and clocks?clocks?

What do bees What do bees have to do with have to do with

time and time and clocks?clocks?

1. Bees can keep appointments with flowers

2. Finding the molecular basis

3. Broad results

4. Two specific examples

Outline:

Natural HistoryNatural History Bees can learn to visit discreet resources Bees can learn to visit discreet resources

at specific times of dayat specific times of day Many plants have circadian rhythm of Many plants have circadian rhythm of

nectar, pollen, and scent productionnectar, pollen, and scent production– Plants have endogenous rhythmPlants have endogenous rhythm

Bees exhibit floral constancyBees exhibit floral constancy– Odor, color, and shapeOdor, color, and shape– TimeTime

Linnaeus' flower clockLinnaeus' flower clock

Goat’s beard:

3am

Chicory: 4:30am

Field Thistle: 6:00am

Hawkweed: 7:00am

Ice Plant: 10:00am

Cat’s Ear: 9:00am

Moore & Rankin (1983)

Time-training beesTime-training bees

Train a single colony to Train a single colony to visit different feeders at visit different feeders at different times of daydifferent times of day

Do this at a time of the Do this at a time of the year when bees will year when bees will specialize on a single good specialize on a single good food sourcefood source

Collect during anticipationCollect during anticipation Analyze:Analyze:

– Time of dayTime of day– Time of trainingTime of training– Active vs. inactiveActive vs. inactive

tAM

Time of collection

Tim

e of

tra

inin

g

cPMcAM

tPM

Active / anticipating

Active / anticipating

Inactive

Inactive

Time of collection:Time of collection: many genesmany genes– Circadian / rhythmic behaviorCircadian / rhythmic behavior– Cytoskeleton / cell adhesionCytoskeleton / cell adhesion– Fat metabolismFat metabolism

Time of training:Time of training: few genesfew genes– Signaling / ion transportSignaling / ion transport– Vesicle / secretory pathwaysVesicle / secretory pathways

Active vs. not:Active vs. not: many genesmany genes– Ribosome and translationRibosome and translation– Cation transportCation transport– Synapse / nerve communicationSynapse / nerve communication– Mitochondria / ATPMitochondria / ATP

Clock genes are affected by trainingClock genes are affected by training

Oxford Univ.

Clock genes are affected by trainingClock genes are affected by training

Image from Panda (2002)

It’s actually more complicated than that…..

Clock genes are affected by trainingClock genes are affected by training

Oxford Univ.

Clock genes are affected by trainingClock genes are affected by training

Morning trained bees exhibit clock gene expression patterns similar to bees freely fed

Afternoon trained bees

Morning trained bees

Clock genes are affected by trainingClock genes are affected by training

Morning trained bees exhibit clock gene expression patterns similar to bees freely fed

Afternoon trained bees

Morning trained bees

Clock genes are affected by trainingClock genes are affected by training

Afternoon trained bees

Morning trained bees

Cycle A

Period

Reward CircuitryReward Circuitry

Dopamine and octopamine Dopamine and octopamine receptors are upregulated in receptors are upregulated in anticipating beesanticipating bees– Hypersensitization of the Hypersensitization of the

reward system in the brainreward system in the brain Previous studies suggest Previous studies suggest

links between reward and links between reward and circadian rhythmscircadian rhythms– Addictive drugs can cause Addictive drugs can cause

clock shiftsclock shifts– Reward seeking is often Reward seeking is often

circadiancircadian

AcknowledgmentsAcknowledgments

Gene RobinsonGene Robinson Sandra Sandra

Rodriguez-ZasRodriguez-Zas Darrell MooreDarrell Moore

– Byron Van NestByron Van Nest– Jennifer JohnsonJennifer Johnson– Sam BoydSam Boyd

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