Western Yellowjacket

Vespula pensylvania, the western yellowjacket, is a social, ground-nesting wasp native to western North America. They aggressively protect their nests, and, like other vespid wasps, can sting repeatedly. Adult workers forage continually for high protein foods, mostly small insects, caterpillars, and spiders, and they sometimes scavenge on dead animals to feed their brood. Vespula pensylvania is found in all states west of the Rocky Mountains, from Mexico up through western Canada. Although it has a more limited distribution than either the closely-related and biologically similar common yellowjacket Vespula vulgaris or the German yellowjacket Vespula germanica (which have both recently become major pests in non-native habitats around the world, especially in the southern hemisphere) V. pensylvania also has a high potential for invasiveness. Since 1919 there have been sporadic reports of the western yellowjacket in Hawaii, and in 1978, populations there exploded to become a public nuisance and threat to endemic Hawaiian insect fauna. A western yellowjacket queen starts to build a nest in the spring, which matures into a large colony of up to several thousand workers by fall. At this time the colony declines and only new queens overwinter. However, in warm climates, such as California and Hawaii, colonies can survive longer than the several summer months they last in their native range, growing to enormous size with the potential to devastate surrounding insect populations and create a large, difficult to control public nuisance. If their nests can be located, physically or chemically destroying them are effective means of population control. Toxic baits, in which attractants are laced with insecticides and offered to workers to feed to larvae and the queen can also be successful in destroying a colony. Baited traps are also used to monitor and assess population numbers. Although Vespula pensylvania has similar yellow and black coloration patterns to other yellowjackets (wasps of the genera Vespula and Dolchivespula), the complete yellow ring around their eye is a reliable distinguishing characteristic. (CABI 2011; Kweskin 2009; Wikipedia 2011)

A recent study published in the Nature journalScientific Reportshighlights a newly identified virus—named Moku after the Hawaiian Island from which it was isolated—in the invasive wasp,Vespula pensylvanica. The research also warns that transmission of these kinds of viruses, especially from invasive species which can spread viruses to new locations, is a threat to pollinator health worldwide.

Particularly under threat are honey bees, which are as vital to ourfood systemsas the crops they pollinate, and which are prone to a range of emergent diseases including Moku and Deformed wing virus (DWV).

The Moku virus was identified through a collaboration of institutes with complementary expertise.

Purnima Pachori of the Platforms & Pipelines Group at the Earlham Institute (EI) carried out the bioinformatics work of separating out host and viral genetic material, which allowed for the analysis and identification of the novel Moku virus led by Gideon Mordecai (based at the time at the Marine Biological Association (MBA), Plymouth).

“It’s brilliant that our computational biology expertise at EI could contribute to the characterisation of a new virus which can be athreatto pollinator health worldwide” said Purnima.

It was through work at the MBA that the true uniqueness of the Moku virus revealed itself. Gideon Mordecai said, “The use of next generation gene sequencing techniques has led to a rapid increase in virus discovery, and is a powerful tool for investigating the enormous diversity of viruses out there.”

The study has highlighted the importance of monitoringinvasive speciesfor broad-range viruses as well as the potential for transmission of these pathogens. Dr Declan Schroeder, Head of the Virus Ecology Group at the MBA explains: “The true significance of this discovery lies in the potential ramifications that a new biological invasion could cause. Could we be seeing history repeating itself? Similar to the Spanish invasion of the Inca and Aztec empires in the sixteenth and seventeenth centuries, it was the smallpox and measles viruses that inflicted the most damage on the individuals of these populous nations. Here we are seeing an invasive wasp bringing in a new virus to honey bees.”

The likelihood is that Moku has the ability to spread throughout the endemic population of honey bees in Hawaii. Gideon Mordecai concludes that “future challenges will be assessing the biological relevance of these novel pathogens and the role they play in the ecology of their hosts.”

Explore further:New study reveals widespread risk of infectious diseases to wild beesJournal reference:Scientific Reports

Provided by: Earlham Institute

Read more at:http://phys.org/news/2016-11-highlights-threat-bees-worldwide.html#jCp