Appointment Keeping in Honey Bees: Molecular Clocks

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Appointment Keeping in Honey Bees Molecular
Clocks
N. L. Naeger University of Illinois,
Urbana-Champaign
BeeSpace Workshop, 21 May 2009
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What do bees have to do with time and clocks?
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What do bees have to do with time and clocks?
Outline

• Bees can keep appointments with flowers
• Finding the molecular basis
• Broad results
• Two specific examples

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Natural History

• Bees can learn to visit discreet resources at
  specific times of day
• Many plants have circadian rhythm of nectar,
  pollen, and scent production
• Plants have endogenous rhythm
• Bees exhibit floral constancy
• Odor, color, and shape
• Time

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Linnaeus' flower clock
Ice Plant 1000am
Goats beard 3am
Cats Ear 900am
Chicory 430am
Hawkweed 700am
Field Thistle 600am
Moore Rankin (1983)
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Time-training bees

• Train a single colony to visit different feeders
  at different times of day
• Do this at a time of the year when bees will
  specialize on a single good food source
• Collect during anticipation
• Analyze
• Time of day
• Time of training
• Active vs. inactive

Time of collection
cPM
cAM
tAM
Active / anticipating
Inactive
Time of training
tPM
Active / anticipating
Inactive
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• Time of collection many genes
• Circadian / rhythmic behavior
• Cytoskeleton / cell adhesion
• Fat metabolism
• Time of training few genes
• Signaling / ion transport
• Vesicle / secretory pathways
• Active vs. not many genes
• Ribosome and translation
• Cation transport
• Synapse / nerve communication
• Mitochondria / ATP

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Clock genes are affected by training
Oxford Univ.
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Clock genes are affected by training
Its actually more complicated than that..
Image from Panda (2002)
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Clock genes are affected by training
Oxford Univ.
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Clock genes are affected by training
Morning trained bees exhibit clock gene
expression patterns similar to bees freely fed
Morning trained bees
Afternoon trained bees
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Clock genes are affected by training
Morning trained bees exhibit clock gene
expression patterns similar to bees freely fed
Morning trained bees
Afternoon trained bees
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Clock genes are affected by training
Period
Cycle A
Afternoon trained bees
Morning trained bees
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Reward Circuitry

• Dopamine and octopamine receptors are upregulated
  in anticipating bees
• Hypersensitization of the reward system in the
  brain
• Previous studies suggest links between reward and
  circadian rhythms
• Addictive drugs can cause clock shifts
• Reward seeking is often circadian

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Acknowledgments

• Gene Robinson
• Sandra Rodriguez-Zas
• Darrell Moore
• Byron Van Nest
• Jennifer Johnson
• Sam Boyd
• BeeSpace