Appointment Keeping in Honey Bees: Molecular Clocks N. L. Naeger University of Illinois, Urbana-Champaign BeeSpace Workshop, 21 May 2009

What do bees have to do with time and clocks?

1.Bees can keep appointments with flowers 2.Finding the molecular basis 3.Broad results 4.Two specific examples Outline:

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

Linnaeus' 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 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 tAM Time of collection Time of training cPMcAM tPM Active / anticipating Inactive

 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

Clock genes are affected by training Oxford Univ.

Clock genes are affected by training Image from Panda (2002) It’s actually more complicated than that…..

Clock genes are affected by training Oxford Univ.

Clock 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 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 training Afternoon trained bees Morning trained bees Cycle A Period

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

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