U.S. flagAn official website of the United States government
                    Here's how you know **Official websites use .gov**
                            
                            A **.gov** website belongs to an official government organization in the United States.
 **Secure .gov websites use HTTPS**
                            
                            A **lock** (                            
                              A locked padlock                                                      
                            
                            ) or **https://** means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.


Menu Agricultural Research Service
						
                    U.S. DEPARTMENT OF AGRICULTURE
 Carl Hayden Bee Research Center: Tucson, AZ
 close



    Research

                    Research Projects
                                    Publications
                                    Collaborations
                                    News
                People

                    Staff Listing
                                    Careers


        


                    Information
                        Africanized Honey Bees
                                    Bee Safety
                                    Online Books
                                    Other NewsSearch small
                    Search
            
            ARS Home
                                About ARS
                                Contact Us




ARS Home Pacific West Area Tucson, Arizona Carl Hayden Bee Research Center Research Publications at this Location





- ARS National Programs
- Search for a scientific manuscript
- Search for a research project
- ARS Software
- Programs and Projects
- Collaborations
- Subjects of Investigation
- Publications
- Cold Storage Overview
- Why put colonies in cold storage to overwinter?
- When to put colonies in cold storage?
- Which colonies to put into cold storage?
- Cold Storage Overwintering Tool
- Overview
- Objective 1: Climate effects on bloom and floral rewards
- Objective 2. Landscape level nutrition models
- Objective 3: Determine pollinator number, diversity and pathogen load
- Objective 4: Develop a management plan for overwintering colonies in cold storage
- Outcomes
- Varroa Overview
- Varroa mite life cycle and reproduction
- Varroosis
- How to Monitor, Sample, and Treat for Varroa
- Current Research: Mite Migration
- Introduction
- BEEPOP+ Model

Title:   Author  item
                                            DeGrandi-Hoffman, Gloriaitem
                                            Chambers, Mona
  Submitted to: Environmental Entomology
                                    Publication Type: Peer Reviewed Journal
                                    Publication Acceptance Date: 4/19/2006
                                    Publication  Date: 8/20/2006
                                    Citation: DeGrandi-Hoffman, G., Chambers, M.  2006. Effects of Honey Bee (Hymenoptera: Apidae) Foraging on Seed Set in Self-fertile Sunflowers (Helianthus annuus L.).  Environ. Entomol. 35(4): 1103-1108.Interpretive Summary: Some commercial sunflower varieties can pollinate themselves as florets mature and set seed.  Whether seed set can be improved on such self-pollinating varieties by introducing honey bees is not clear.  We compared seed set between sunflowers exposed to bees with those that were bagged so that bees could not forage on the florets.  Ten sunflower varieties were evaluated.  We also examined the role of temperature and relative humidity on seed set and whether the effects could be mitigated by honey bee pollination.  In the first planting when temperatures were significantly higher than in the second, the number of foraging honey bees was smaller than in the second, and seed set for most cultivars did not differ between flower heads that were bagged and ones where bees could forage.  In the second planting though, a majority of cultivars had significantly greater seed set when florets were exposed to bees compared with when they were not.  The weight of seeds from open-pollinated florets also was greater than from those where bees were excluded.  Environmental conditions played a role in seed set. In the first planting, average maximum and minimum temperatures were significantly higher than in the second, and seed set was significantly lower in flower heads where bees were excluded.  Under the high temperature conditions though, some cultivars set four times more seed on open-pollinated flower heads compared with those that were bagged.  These results suggest that foraging activity and cross-pollination by bees might mitigate reductions in seed set caused by high temperatures.  The study also shows that bee pollination can improve seed yields in self-pollinating varieties if populations of bees are sufficiently large.
                                Technical Abstract: Ten self-fertile commercial sunflower cultivars were evaluated for seed set with and without exposure to bees.  In the first planting, the number of foraging honey bees was smaller than in the second, and seed set for most cultivars did not differ between those excluding bees and ones that were open-pollinated.  In the second planting, a majority of cultivars had significantly greater seed set when capitula were exposed to bees compared with when they were not.  The weight of seeds from open-pollinated capitula was greater than from those where bees were excluded.  Environmental conditions also played a role in seed set.  In the first planting, average maximum and minimum temperatures were significantly higher than in the second, and seed set was significantly lower in capitula where bees were excluded.  Under the high temperature conditions some cultivars set four times more seed on open-pollinated capitula compared with those that were bagged.  These results suggest that foraging activity and cross-pollination by bees might mitigate reductions in seed set caused by high temperatures.


Return to top


Connect with ARS Sign up


ARS Home
                            USDA.gov
                            Plain Writing
                            Policies & Links
                            Civil Rights Statements
                            FOIA
                            Accessibility Statement
                            Privacy Policy
                            Non-Discrimination Statement
                            Quality of Information
                            USA.gov
                            WhiteHouse.gov