Effect of Varroa destructor, Wounding and Varroa Homogenate on Gene Expression in Brood and Adult Honey Bees

Abstract

Honey bee (Apis mellifera) gene expression related to immunity for hymenoptaecin (AmHym) and defensin-1 (AmDef-1), longevity for vitellogenin (AmVit2) and stem cell proliferation for poly U binding factor 68 kDa (AmPuf68) was compared following Varroa destructor parasitism, buffer injection and injection of V. destructor compounds in its homogenate. In adults, V. destructor parasitism decreased expression of all four genes, while buffer injection decreased expression of AmHym, AmPuf68 and AmVit2, and homogenate injection decreased expression of AmPuf68 and AmVit2 but increased expression of AmDef-1 relative to their respective controls. The effect of V. destructor parasitism in adults relative to the controls was not significantly different from buffer injection for AmHym and AmVit2 expression, and it was not significantly different from homogenate injection for AmPuf68 and AmVit2. In brood, V. destructor parasitism, buffer injection and homogenate injection decreased AmVit2 expression, whereas AmHym expression was decreased by V. destructor parasitism but increased by buffer and homogenate injection relative to the controls. The effect of varroa parasitism in brood was not significantly different from buffer or homogenate injection for AmPuf68 and AmVit2. Expression levels of the four genes did not correlate with detectable viral levels in either brood or adults. The results of this study indicate that the relative effects of V. destructor parasitism on honey bee gene expression are also shared with other types of stresses. Therefore, some of the effects of V. destructor on honey bees may be mostly due to wounding and injection of foreign compounds into the hemolymph of the bee during parasitism. Although both brood and adults are naturally parasitized by V. destructor, their gene expression responded differently, probably the result of different mechanisms of host responses during development.

Quantitative proteomics reveals divergent responses in Apis mellifera worker and drone pupae to parasitization by Varroa destructor

“…There is considerable debate on the nature of the Varroa-Apis interaction and whether the mites possess the ability to suppress the host's immune response (Gregory et al, 2005, Kuster et al, 2014, Khongphinitbunjong et al, 2015, Koleoglu et al, 2017. Through label free analysis of the parasitized worker and drone pupae, the proteins significantly altered in abundance were examined for the presence of immune factors.…”

Interaction of field realistic doses of clothianidin and Varroa destructor parasitism on adult honey bee (Apis mellifera L.) health and neural gene expression, and antagonistic effects on differentially expressed genes

“…destructor parasitism is a very serious health problem for honey bees as the mite not only damages the bee by feeding on the hemolymph and fat tissue [7,8], but it also vectors a number of viruses with deformed wing virus (DWV) being the most pathogenic to honey bees [9,10]. Additionally, V. destructor impairs the humoral and cellular responses of the immune system of honey bees [11,12,13]. Furthermore, V. destructor has been reported to affect the neural processes of honey bees by impairing grooming behaviour [14], non-associative learning [15] and homing ability in worker bees [16].…”

Using an in vitro system for maintaining Varroa destructor mites on Apis mellifera pupae as hosts: studies of mite longevity and feeding behavior

“…Several studies have shown a correlation between this obligate parasite and viral load of the deformed wing virus (DWV), the Israeli acute paralysis virus (IAPV), and other less well-known viruses (Chen et al 2004;Di Prisco et al 2011a, b;Yang and Cox-Foster 2007). Additionally, varroa causes direct physical damage/deformities from feeding (Kanbar and Engels 2003), compromises host immune systems (Koleoglu et al 2017), and increases host mortality (Guzman-Novoa et al 2010). As a harmful pest of agriculturally important honey bees, varroa poses a tremendous threat to the bee-keeping industry (Gibbs and Muirhead 1998;Ellis et al 2010), and thus food security.…”