title: Spore Loads May Not be Used Alone as a Direct Indicator of the Severity of Nosema ceranae Infection in Honey Bees Apis mellifera (Hymenoptera:Apidae).
abstract: Nosema ceranae Fries et al., 1996, a microsporidian parasite recently transferred from Asian honey bees Apis cerana F., 1793, to European honey bees Apis mellifera L., 1758, has been suspected as 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 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 increase of spore counts caused by pollen feeding. These results indicate that spore loads may not be used alone as a direct indicator of the severity of N. ceranae infection in honey bees.
authors.affiliation: College of Animal Sciences, Zhejiang University, Hangzhou, Zhejiang 310058, P.R. China. USDA-ARS Bee Research Laboratory, Beltsville, MD 20705.
authors.forename: Huo-Qing
authors.initials: HQ
authors.lastname: Zheng
authors.affiliation: College of Animal Sciences, Zhejiang University, Hangzhou, Zhejiang 310058, P.R. China.
authors.forename: Zhe-Guang
authors.initials: ZG
authors.lastname: Lin
authors.affiliation: USDA-ARS Bee Research Laboratory, Beltsville, MD 20705. College of Bee Science, Fujian Agriculture and Forestry University, Fuzhou, Fujian 350002, P.R. China.
authors.forename: Shao-Kang
authors.initials: SK
authors.lastname: Huang
authors.affiliation: USDA-ARS Bee Research Laboratory, Beltsville, MD 20705.
authors.forename: Alex
authors.initials: A
authors.lastname: Sohr
authors.affiliation: USDA-ARS Bee Research Laboratory, Beltsville, MD 20705.
authors.forename: Lyman
authors.initials: L
authors.lastname: Wu
authors.affiliation: College of Animal Sciences, Zhejiang University, Hangzhou, Zhejiang 310058, P.R. China. judy.chen@ars.usda.gov.
authors.forename: Yan Ping
authors.initials: YP
authors.lastname: Chen
mesh_terms: D000818:Animals; D001516:Bees / Q000378:metabolism / Q000382:microbiology*; D006790:Host-Parasite Interactions; D016881:Microsporidiosis / Q000662:veterinary*; D016818:Nosema / Q000254:growth & development*; D011058:Pollen / Q000382:microbiology*; D013172:Spores, Fungal / Q000254:growth & development* / Q000528:radiation effects; D014819:Vitellogenins / Q000378:metabolism
chemical_list: D014819:Vitellogenins
keywords: Nosema ceranae; longevity; pollen; spore load; vitellogenin