PHEROMONAL AND GENETIC REGULATION OF HONEY BEE FORAGING BEHAVIOR

• Sponsoring Institution: National Institute of Food and Agriculture
• Project Status: COMPLETE
• Funding Source: NRI COMPETITIVE GRANT
• Reporting Frequency: Annual
• Accession No.: 0196326
• Grant No.: 2003-35302-13485
• Proposal No.: 2003-01620
• Project Start Date: Aug 1, 2003
• Project End Date: Jul 31, 2006
• Grant Year: 2003
• Program Code: [51.2]- (N/A)

Recipient Organization
UNIVERSITY OF CALIFORNIA, DAVIS
410 MRAK HALL
DAVIS,CA 95616-8671

Performing Department
ENTOMOLOGY

Non Technical Summary
Insect societies display a remarkable division of labor where worker honey bees change the tasks they perform as they age. When workers begin foraging, some specialize on collecting nectar, some pollen, and some show less specialization and collect both. Differences in foraging behavioral decisions are heritable, have been artificially selected, and major genes affecting these behavioral traits have been mapped. Chemical substances (pheromones) produced by larval worker honey bees affect foraging behavior. In addition, octopamine, a behavior modifying chemical found in insect brains, has been shown to affect behavioral traits associated with pollen foraging behavior. Little is known about how genes, pheromones, and neural chemistry interact and affect behavior. This is an exciting opportunity study these interactions with a beneficial insect of enormous agricultural importance, the honey bee. Regulation of insect behavior with pheromones has been a major objective of crop pest management for more than 25 years. Hopefully, this project will lead to the development of methods to manipulate the foraging behavior of honey bees to increase their beneficially effects on crop pollination.

Animal Health Component

50%

Research Effort Categories

Basic

50%

Applied

50%

Developmental

(N/A)

Classification

Knowledge Area (KA)	Subject of Investigation (SOI)	Field of Science (FOS)	Percent
211	3010	1080	100%

Knowledge Area
211 - Insects, Mites, and Other Arthropods Affecting Plants;

Subject Of Investigation
3010 - Honey bees;

Field Of Science
1080 - Genetics;

Keywords

bees

european bees

insect pheromones

insect genetics

gene regulation

foraging behavior

insect behavior

apis mellifera

amines

insect larvae

foraging

syndromes

octopamine

pollen

pollination

pollinators

insect physiology

mechanism of action

Goals / Objectives
The objective of this project is to better understand honey bee foraging behavior. The project specifically addresses factors that modulate and release pollen foraging behavior with the aim of developing methods to manipulate foraging behavior to increase the efficacy of honey bee colonies as pollinators of agricultural crops.

Project Methods
The proposed research addresses five questions: 1) Are larval cues regulating a suite of foraging behavioral traits that we have identified? 2) Are in foraging behavior between selected strains of bees a consequence of differences in sensitivity to larval cues? 3) Does the biogenic amine octopamine modulate the suite of behavioral traits associated with foraging, thereby suggesting a common physiological link among them? 4) Do bees from the high and low pollen hoarding strains differ in brain titers of octopamine and other biogenic amines? 5) Do bees from the high and low pollen hoarding strains differ in their sensitivities to octopamine? Tests will be conducted for the effects of larval pheromones on a suite of behavioral and sensory traits that have been shown to associate with pollen foraging. Likewise tests will be performed for the effects of known neuromodulators for their effects on the sensitivity of bees to pollen foraging releasing and inhibiting stimuli. Stocks of honey bees that have been artificially selected for their differences in pollen and nectar foraging behavior will be used to explore the interactions of neuromodulators, foraging stimuli, and pollen foraging behavior.

Progress 08/01/03 to 07/31/06

Outputs
Six experiments are outlined in the proposal. Experiment 4 is complete and the results are published selected for high and low pollen hoarding. Annals of the Entomological Society of America 97: 1313-1319). We demonstrated that newly-emerged workers from the high and low pollen hoarding strains do not differ in brain titres of octopamine, dopamine, or serotonin, but do differ in blood titres of juvenile hormone.

Experiment 1a was completed in the summer of 2004. Data have been analyzed but not yet published. Hypothesis 1 was supported by the results.

Experiment 1b will be completed in May and June of this year. This experiment is already ongoing.

Experiment 2 was conducted during the summer of 2004 but the data have not yet been analyzed. We modified the experiment and conducted it in observations hives making it an observation intensive experiment that requires many hours to decode tape recorded data entries.

Experiment 3 was completed during the summer of 2004. The data have been analyzed. We had an interesting but unexpected result that made us change our initial hypothesis with respect to the effects of octopamine feeding on foraging behavior of our selected high and low pollen hoarding bees that were used in the experiment. Therefore, we are replicating the experiment this summer (2005) in order to test our new hypothesis.

Experiment 5 was linked to experiment 4. Again the results of this experiment caused us to reformulate our hypothesis of how octopamine was affecting the foraging behavior of wild-type and our high and low strain bees. We are replicating this experiment this summer.

Undoubtedly one or more of these experiments will need to be repeated next season (Spring and Summer 2006). The additional six months requested will give us the time we need to do any necessary repeat or follow-up experiments and provide my graduate student time to write the research papers.

Impacts
A better understanding of the mechanisms involved in foraging differences worker honey bees will help us develop colony management schemes to increase the pollination efficacy of colonies.

Publications

• Schulz, D. J., T. Pankiw, M. K. Fondrk, G. E. Robinson, and R. E. Page. 2004. Comparison of juvenile hormone hemolymph and octopamine brain titers in honey bees (Hymenoptera: Apidae).

Progress 01/01/04 to 12/31/04

Outputs
We continued our studies of the effects of brood and brood pheromone on the life history and foraging behavior of worker honey bees. These studies are still underway and not ready to report.

Impacts
A better understanding of the mechanisms involved in foraging differences worker honey bees will help us develop colony management schemes to increase the pollination efficacy of colonies.

Publications

• No publications reported this period

Progress 01/01/03 to 12/31/03

Outputs
We tested the effects of brood and brood pheromone on the foraging behavior of workers from the high and low pollen hoarding strains. We found that, as expected, the presence of brood and brood pheromone resulted in an increase in pollen foraging behavior. The high strain workers, as expected, collected larger loads of pollen. However, the strains responded equally to increases in brood and brood pheromone suggesting that they do not have differential sensitivity to the pollen foraging releasing stimuli associated with brood.

Impacts
A better understanding of the mechanisms involved in foraging differences between the high and low strain bees will help us develop colony management schemes to increase the pollination efficacy of colonies.

Publications

• No publications reported this period