Viruses in the Invasive Hornet Vespa velutina

Abstract

The Asian yellow-legged hornet Vespa velutina nigrithorax, a major predator of honeybees, is spreading in Europe in part due to a lack of efficient control methods. In this study, as a first step to identify biological control agents, we characterized viral RNA sequences present in asymptomatic or symptomatic hornets. Among 19 detected viruses, the honey bee virus Deformed wing virus-B was predominant in all the samples, particularly in muscles from the symptomatic hornet, suggesting a putative cause of the deformed wing symptom. Interestingly, two new viruses closely related to Acyrthosiphon pisum virus and Himetobi P virus and viruses typically associated with honey bees, Acute bee paralysis virus and Black queen cell virus, were detected in the brain and muscles, and may correspond to the circulation and possible replication forms of these viruses in the hornet. Aphid lethal paralysis virus, Bee Macula-like virus, and Moku virus, which are known to infect honey bees, were also identified in the gut virus metagenome of hornets. Therefore, our study underlined the urgent need to study the host range of these newly discovered viruses in hornets to determine whether they represent a new threat for honey bees or a hope for the biocontrol of V. velutina.

Diversity and Global Distribution of Viruses of the Western Honey Bee, Apis mellifera

“…Furthermore, there is increasing evidence that viruses first described in honey bees are not restricted to this host and can be transmitted between genera [28,30,156]. Symptoms caused in well-studied bee species are wing deformities [167,168], reduced reproductive success [169] and mortality [156], but the impact on wild bee health is more difficult to assess, since most of these are solitary species that cannot be reared artificially. The commercialization of certain pollinators provides the opportunity for pathogens to spread both within managed honey bees or other commercial pollinators, as well as to wild pollinators.…”

“…The mechanisms of dispersal of viruses of honey bees could be investigated by studying the prevalence and biogeography of newly described viruses that do not yet occur globally. The spread of invasive species such as Vespa velutina and Apis florea [113,168] and vectors such as V. destructor and T. mercedesae is also alarming, as these species are known to be infected by viruses of A. mellifera [138,172,173].…”

RNAseq of Deformed Wing Virus and Other Honey Bee-Associated Viruses in Eight Insect Taxa with or without Varroa Infestation

“…While the replication of DWV genotypes has been detected in other hosts, such as Varroa [41,42], ants (Formicidae) [43], stingless bees (Apidae) [44], solitary bees (Colletidae [44], Andrenidae [13] and Megachilidae [45]) and hornets (Vespidae) [46], and DWV has been detected in symptomatic (deformed) bumblebees (Bombus spp.) [47] and hornets (Vespa velutina) [48], conclusive studies on the ability of DWV to cause pathology in non-honey bee hosts have largely been limited to bumblebees [15,19]. Another recent study, however, found no effect on mortality in experimentally infected bumblebees [49], suggesting that DWV infection is not uniformly virulent in bumblebees.…”

Bee Viruses: Routes of Infection in Hymenoptera

“…Besides DWV other viruses have also been detected in wasp species, such as IAPV (Yañez et al, 2012b), Moku virus (Garigliany et al, 2017) ALPV, KBV, and BQCV (Mazzei et al, 2019;Yang et al, 2019). An RNAseq analysis of different tissues of Asian hornets, V. velutina, recently identified 18 virus species and added ABPV, BeeMLV and DWV-C to the list of bee associated viruses found in wasp species (Dalmon et al, 2019). Furthermore, the same study showed the presence of DWV, BQCV, and ABPV in tissues other than the gut, which suggests that these viruses cause a real infection in V. velutina.…”