|ZHENG, HUOQING - Zhejiang University
|LIN, ZHEGUANG - Zhejiang University
|HUANG, SHAOKANG - Fujian Agricultural & Forestry University
|Chen, Yanping - Judy
Submitted to: Journal of Economic Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/15/2014
Publication Date: 11/15/2014
Citation: Zheng, H., Lin, Z., Huang, S., Sohr, A.R., Wu, L., Chen, Y. 2014. Nosema ceranae spore loads may not provide a good indicator of Apis mellifera health. Journal of Economic Entomology. 107(6):2037-2044.
Interpretive Summary: Nosemosis is a disease of the digestive tract in honeybees caused by the spore-forming parasite Nosema. Spore load has been commonly used to describe the intensity of Nosema infection. However, in the present study, we showed that the load of Nosema spore was positively correlated with the amount of pollen consumed. Further, we also showed that there was positive correlation between the amount of pollen consumption and honey bee longevity. Therefore, we conclude that spore loads may not be sufficient as a general marker of overall health status in Nosema-infected bees. The information obtained from this study should be of interest to the researchers, graduate students, apiary inspectors, and beekeepers in the honey bee society worldwide.
Technical Abstract: Nosema ceranae, a microsporidia parasite recently transferred from Asian honey bees Apis cerana to European honey bees A. mellifera, has been suspected to be one of the major culprits of the worldwide honey bee colony losses. Spore load is a commonly used criterion to describe the intensity of Nosema infection. In this study, by providing Nosema-infected bees with sterilized pollen, we confirmed that pollen feeding increased the spore loads of honey bees by several times either in the presence or absence of a queen. By changing the amount of pollen consumed by bees in cages, we showed that spore loads increased with an increase in pollen consumption. Nosema infections typically decrease honey bee longevity and transcription of vitellogenin, either with or without pollen feeding. However, the reduction of pollen consumption had a greater impact on honey bee longevity and vitellogenin level than the impact of the increase of spore counts caused by pollen feeding. As a result, when bees were fed with different amounts of pollen, N. ceranae spore loads correlated positively with honey bee longevity and vitellogenin levels, two commonly used honey bee health indexes. These results indicate that pollen consumption needs to be considered in studies of host-parasite interactions in bees and that measurements of Nosema spore loads may not provide a good indicator for the health of Nosema-infected bees.