Location:2012 Annual Report
1a. Objectives (from AD-416):
Objective 1: Investigate geographical differences in morbidity and mortality from Nosema sp., including interactions with other biotic and abiotic challenges in full colony studies in stationary location in Weslaco, TX. (This objective is a part of a larger experiment conducted in a number of different locations throughout the United States). Objective 2: Determine individual bee morbidity and mortality from Nosema sp., including interactions with other biotic and abiotic challenges using caged studies. Objective 3: Investigate the honey bee defense pathways against microbial pathogens. Objective 4: Develop diagnostic tools for field and laboratory detection and monitoring of honey bees diseases (Nosema ceranae).
1b. Approach (from AD-416):
A new apiary will be established to conduct Grand Experiment study described in "Biotic threats" section. Thirty honey bee colonies will be maintained at Weslaco, TX, site by the Research Unit personnel. Bee samples will be collected bi-weekly and stored in -80 C; pollen samples will be collected on a monthly basis and shipped to collaborators for pesticide residue analysis. Cage Experiment: Nosema ceranae infection study will be conducted in Weslaco in collaboration with Dr. Webster, Kentucky State University. Bees will be infected with different biotypes of N. ceranae in cages. Honey bee samples will be collected at the different stages as the disease progresses to determine the differential gene expression in response to infection. Bee samples collected from the cage infection study will be analyzed using quantitative PCR (qRT-PCR) to estimate the differences in the level of bee immune responses between Nosema-infected and healthy bees. Infection of bees with N. cerana will be confirmed using DNA-base method and microscopic observation of the dissected bees. Dipstick assay: We propose to develop a highly sensitive dipstick test for detection of Nosema infection in bee colonies. The test is based on the antibodies of N. ceranae raised in small animals, and it will be able to detect Nosema antigen in honey bee samples. A dipstick assay will be evaluated and optimized on honey bee samples collected in six different locations in the U.S. Production and marketing of the dipsticks is not included in the scope of this study.
3. Progress Report:
Objective 1: Investigate geographical differences in morbidity and mortality from Nosema sp., including interactions with other biotic and abiotic challenges in full colony studies in stationary location in Weslaco, TX. This objective is a part of a larger "Stationary Apiaries" experiment conducted at six different locations throughout the US and consists of two replicate two-year trials (2009-2011 and 2011–2013). Study was conducted as described in (1b); samples were collected and analysed by the collaborating laboratories. Progress reports were presented at the Research meetings and the results were published by the collaborators: Aronstein, K., F. Drummond, B. Eitzer, J. Ellis, J. Evans, N. Ostiguy, S. Sheppard, M. Spivak, and K. Visscher. The CAP Stationary Apiary Project: Colony strength data analysis 2009-2010. American Bee Reseach Conference Annual Meeting, 2011. Galveston, TX. Drummond, F., K. Aronstein, B. Eitzner, J. Ellis, J. Evans, N. Ostiguy, W. Sheppard, M. Spivak, and K. Visscher. Honey bee colony collapse in stationary hives across the U.S. Society for Invertebrate Pathology Annual Meeting. 2011. Halifax, Canada. Drummond, F., K. Aronstein, B. Eitzner, J. Ellis, J. Evans, N. Ostiguy, W. Sheppard, M. Spivak, and K. Visscher. Honey bee colony losses in stationary hives across the U.S. ESA, 2011. Reno, NV. Cox, R., and K.A. Aronstein. Nosema apis in small nucleus colonies. Proceedings of the American Bee Research Conference, 2012. Abstract in American Bee Journal 4:400. Grozinger, C.M, H.L. Holt, F.J. Richard, and K.A. Aronstein. 2012. Genomics analysis of social immunity in honey bees. Proceedings of the American Bee Research Conference, 2012. Abstract in American Bee Journal 4:401. Objective 2: Comparative Virulence of N. apis and N. ceranae in Cage Experiments. This study investigated the effects of different species of Nosema (Nosema apis and Nosema ceranae) on host mortality, infectivity, and pathogen ability to produce environmental spores. In three independent trials we determined the level of bee mortality for different species of Nosema using a range of inoculums (50,000 to 50 spores/ per bee). Data analysis showed that: N. apis infection produced higher bee mortality in a shorter period of time when compared with N. ceranae. By week four, bee mortality split in accordance with the treatment groups: the higher mortality group of N. apis (50,000, 5,000 and 500 spores/bee) along with the two highest doses of N. ceranae (50,000 and 5,000 spores/bee); and the lower mortality group was composed of the negative control (no spores) and the lowest doses of both species (50 spores per bee). Mortality in the cages fed 500 spores of N. ceranae fell in the middle between the two groups. The bees in the high mortality group (H) reached LT 50 by the third week post infection, while the lower mortality group (L) reached LT 50 five weeks post infection. Significantly, at the lower spore concentrations (50 spores/bee), both Nosema species produced mortality that was not significantly different from that in the control cages. Objective 3: Investigate the honey bee defense pathways against microbial pathogens. In collaboration with the Pennsylvania State University, we investigated bee responses to Nosema infection using microarrays. Data analysis showed significant changes in the expression profile of genes affecting metabolic and nutritional status of bees. Data produced in this study presents a unique opportunity to improve our understanding of the highly complex nature of host-pathogen interactions and develop new approaches to disease control. Manuscript is in preparation. Objective 4: Develop diagnostic tools for field and laboratory detection and monitoring of honey bees diseases (Nosema ceranae). A highly specific and sensitive test for detection of Nosema ceranae in bees has been developed and tested using experimental bee samples. Results are published in the Journal of Apicultural Research.