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
                                            KANG, YUN - Arizona State Universityitem
                                            BLANCO, KRYSTAL - Arizona State Universityitem
                                            DAVIS, TALIA - Arizona State Universityitem
                                            WANG, YING - Arizona State Universityitem
                                            DeGrandi-Hoffman, Gloria
  Submitted to: Mathematical Biosciences
                                    Publication Type: Peer Reviewed Journal
                                    Publication Acceptance Date: 2/26/2016
                                    Publication  Date: 3/9/2016
                                    Citation: Kang, Y., Blanco, K., Davis, T., Wang, Y., Hoffman, G.D. 2016. Disease dynamics of honeybees with Varroa destructor as parasite and virus vector. Mathematical Biosciences. 275:71-92.Interpretive Summary: Honey bee colonies often are lost from a combination of Varroa mites and high virus titers. The combination of a parasite and pathogen and the associated reductions in adult bee lifespan erode population numbers. Colonies die because there are not enough adult workers to rear brood, forage and conduct other duties in the hive. We constructed a mathematical model to describe the growth of Varroa populations and spread of virus in honey bee colonies to better understand the conditions and processes that lead to colony death.  The model revealed that colonies can survive if they have virus but are mite-free as long as virus transmission rates are low. This scenario occurred before the introduction of Varroa into the U.S. Virus were commonly detected in colonies, but the bees seemed unaffected. The model also predicted that colonies with Varroa but no virus also can survive, depending on initial mite and colony population sizes. However, the combination of Varroa with virus, led to rapid virus transmission through the mite into the bee population, a persistence of virus infections in the colony population, and inevitable colony death. The ultimate cause of death was an insufficient ratio of adult bees to brood to sustain colony growth. The results of our model analyses indicate that Varroa control strategies need to keep mite levels low throughout the season to insure low virus transmission rates. Colony management strategies that maintain high adult to brood ratios (e.g., high quality queens and good nutrition) in the presence of Varroa and virus also are needed to prevent ratios of adult bees to brood from slipping below critical levels.
                                Technical Abstract: The worldwide decline in honeybee colonies during the past 50 years has often been linked to the spread of the parasitic mite Varroa destructor and its interaction with certain honeybee viruses carried by Varroa mites. In this article, we propose a honeybee-mite-virus model that incorporates (1) parasitic interactions between honeybees and the Varroa mites; (2) 've virus transmission terms between honeybees and mites at di'erent stages of Varroa mites: from honeybees to honeybees, from adult honeybees to the phoretic mites, from brood to the reproductive mites, from the reproductive mites to brood, and from adult honeybees to the phoretic mites; and (3) Allee e'ects in the honeybee population generated by its internal organization such as division of labor. We provide completed local and global analysis for the full system and its subsystems. Our analytical and numerical results allow us have a better understanding of the synergistic e'ects of parasitism and virus infections on honeybee population dynamics and its persistence. Interesting 'ndings from our work include: (a) Due to Allee e'ects experienced by the honeybee population, initial conditions are essential for the survival of the colony. (b) Low adult honeybees to brood ratios have destabilizing e'ects on the system which generate 'uctuating dynamics that lead to a catastrophic event where both honeybees and mites suddenly become extinct. This catastrophic event could be potentially linked to Colony Collapse Disorder (CCD) of honeybee colonies. (c) Virus infections may have stabilizing e'ects on the system, and parasitic mites could make disease more persistent. Our model illustrates how the synergy between the parasitic mite and virus infections consequently generates rich dynamics including multiple attractors where all species can coexist or go extinct depending on initial conditions. Our 'ndings may provide important insights on honeybee diseases and parasites and how to best control them.


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