A laboratory technique to study the effects of Varroa destructor and viruses on developing worker honey bees

Autor: Amanda M. Frake, Thomas E. Rinderer, Kitiphong Khongphinitbunjong, L. I. de Guzman, Matthew R. Tarver
Rok vydání: 2013
Předmět:
Zdroj: Journal of Apicultural Research. 52:262-263
ISSN: 2078-6913
0021-8839
DOI: 10.3896/ibra.1.52.5.14
Popis: Varroa destructor, laboratory-rearing, gel caps Journal of Apicultural Research 52(5): 262-264 (2013) © IBRA 2013 DOI 10.3896/IBRA.1.52.5.14 Many studies of honey bee, Varroa destructor mite and virus interactions can be facilitated if honey bees and mites can be reared in the laboratory. In vitro rearing of honey bees has been successfully demonstrated by several researchers (e.g. Peng et al., 1992 and citations therein; Crailsheim et al., 2013). However, their methods did not use single, tight confinement chambers which V. destructor needs for successful reproduction. The full life cycle of V. destructor in the laboratory has also been achieved but with minimal success (Dietemann et al., 2013). In 1994, Nazzi and Milani showed that 62% of the mites inoculated into newly sealed larvae (NSL) placed inside gelatin capsules (6 mm diameter) reproduced successfully with 3.5 progeny per female. However, this method involves manipulation of NSL. In this study, we assessed the use of larvae (L4 or NSL) naturally developing in a comb as mite-and virus-inoculation hosts. In Trial 1, a frame of brood containing L4 larvae and NSL obtained from a colony was used. Each test brood received one foundress V. destructor collected from NSL. Thereafter, brood cells (L4 larvae = 48 cells; NSL = 30 cells) were individually sealed with a gel cap. The bottom portion of clear gelatin capsules (size 0 or 00) (Solaray; Park City, UT, USA) were cut to fit the rim of a cell (diameter = 5 mm) and then gently pressed onto the comb (Fig. 1.). Mite-inoculation of the NSL group followed the techniques of Kirrane et al. (2011). In brief, one foundress mite was introduced into a small opening created at the edge of a capped brood. Thereafter, the capping was pressed back and sealed with a gel cap. Thirty un-manipulated NSL (no gel cap) served as controls. Trial 2 used L4 larvae (sealed with gel caps) as hosts with the following treatments: a) one mite (n = 31); b) two mites (n = 27); c) no mites and fed 2 µl deformed wing virus (DWV, n = 30); d) one mite and fed 2 µl DWV (n = 30); and control (no mites or DWV, n = 26). Inoculum mites were collected from NSL. DWV lysate was prepared by grinding 10 bees with deformed wings in 10 ml of PBS. Presence of DWV in the lysate was confirmed by qRT-PCR (Nazzi et al., 2012). Thereafter, test brood frames were placed in an incubator (34oC, 60-70% relative humidity). After nine days, each brood cell was examined for mite reproduction. Each pupa was then placed in a 0.5 ml Eppendorf vial with a small hole through the cover and allowed to develop to adulthood in an incubator. Individual bees were weighed at emergence. Overall, about 80% of the V. destructor reproduced. In Trial 1, analysis of variance (ANOVA) showed no difference in fecundity was detected between mites inoculated in L4 (4.0 ± 0.3 progeny) and NSL (3.7 ± 0.4) groups (t
Databáze: OpenAIRE
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