Asian hornet

Vespa velutina

Overview

Photo credits: ©iStockphoto/Alberto Novo; Jean Haxaire
Vespa velutina - Asian Hornet 
Habitat
  • Its habitat is likely to be close to bees hives, in trees or man-made structures. Nests are usually high in trees and man-made structures. 

Description:
Appearance and biology information taken from the Bee Base website;
  • Asian hornet adult workers measure 25mm in length, while queens are 30mm in length.
  • It's abdomen is mostly black except for it's fourth abdominal segment which is a yellow band located towards the rear.
  • It has characteristically yellow legs which accounts for why it is often called the yellow legged hornet and it's face is orange with two brownish red compound eyes (image 1).
  • Download N.I.E.A. ID guide
Asian yellow legged hornet (image 1)

Lifecycle:
  • After winter hibernation, in spring, the queen, usually measuring up to 3 cm, will emerge and seek out an appropriate sugary food source in order to build up energy to commence building a small embryonic or 'primary' nest (image 2).


Queen building 'primary' nest (image 2)



  • During construction of the nest, she is alone and vulnerable but she will rapidly begin laying eggs to produce the future workforce. As the colony and nest size increases, a larger nest is either established around the embryonic nest or they relocate and build elsewhere (image 3 & 4).

  • During the summer, a single colony, on average, produces 6000 individuals in one season. From July onwards, Asian hornet predation on honeybee colonies will begin and increase until the end of November and hornets can be seen hovering outside a hive entrance, waiting for returning foragers. This is the characteristic “hawking” behaviour (image 5). When they catch a returning bee, they will usually sever the head off and take it away and feed off of the protein rich thorax; the brood requires animal proteins which are transformed into flesh pellets and then offered to the larvae.

Asian hornet hawking (image 5). Crown copyright - Bee Base website http://www.nationalbeeunit.com/ gallery/displayImage.cfm?image=145

Asian hornet eating a hoverfly. Crown copyright - Bee Base website http://www.nationalbeeunit.com/ gallery/displayImage.cfm?image=130


  • During autumn, the nest’s priorities shift from foraging and nest expansion to producing on average 350 potential gynes (queens) and male hornets for mating, however, of these potential queens, only a small amount will successfully mate and make it through winter. After the mating period, the newly fertilised queens will leave the nest and find somewhere suitable to over-winter, while the old queen will die, leaving the nest to dwindle and die off.
  • The following spring, the founding queen will begin building her new colony and the process begins again.

Origin and worldwide distribution:
  • The Asian hornet is native to South-East Asia and was probably introduced by accident through imported goods from China. Since its first recording in France in 2005, it has spread to; Spain in 2010, Portugal and Belgium in 2011, Italy in 2012, Germany in 2014 and GB in 2016. Since first being recorded in GB in 2016 a number of nest eradications have taken place. 

Impacts:
  • The Asian hornet is a highly effective predator of honey bees, wasps and other important pollinators, such as hoverflies. The huge size of its colonies (consisting of up to 10,000 individuals per season) means that they can rapidly decimate entire beehives. Observations in France noted losses of 14,000 honey bees per hive per month.
  • Due to its aggressive nature and feeding habits, it could have a serious impact on native insect biodiversity and on pollination services in general. 
  • Given that queen hornets are highly mobile and very adaptable, there is a strong risk that the species will be able to spread rapidly across the landscape, causing significant economic and ecological damage. 

Is it found in Ireland or Northern Ireland?
  • First confirmed sighting in Ireland May 2021. Has not been recorded in Northern Ireland.

How could it get here?
  • Arrival by natural spread or by hitch-hiking upon imported goods or vehicles is consdiered the most likely pathway into Northern Ireland.
  • Wood products and bark, soil (associated with the plant trade) and suitable man-made products (e.g. ceramic pottery associated with garden trade) all provide suitable harbourages for hibernating inseminated V. velutina queens. 

Methods for Prevention:
  • Monitoring pathways of introduction and removing any individuals.
  • Report all sightings.

If you are resident in Northern Ireland you can record your suspected sightings at:
    1. The Asian Hornet Watch app -  the app is available to download from the Apple and Android app stores
    2. the CEDaR online recording form
    3. at iRecord
    4. Or call the Non-Native Invasive Species Team at the Northern Ireland Environment Agency - Tel: 028 9056 9558. E-mail: invasivespecies@daera-ni.gov.uk  
If you are a beekeeper living in Northern Ireland you can register your apiary here  - it will assist us to circulate information quickly to beekeepers if you are already registered at the time of an invasion.
If you are resident in Ireland you can record your suspected sightings at:
Risk assessment:
Further resources:


  • The latest news from the Stop Vespa Velutina in Italy campaign
  • See posts and news on latest discoveries in GB
  • For those beekeepers that might wish to set up monitoring traps, the National Bee Unit in GB have produced some guidance on how to make your own traps. It is important to note that there may be some by-catch by using these monitoring traps, so vigilance is required on a daily basis to avoid killing other species unnecessarily. All efforts must be made to release any by - catch before fatalities occur, but there would be an obvious emphasis on preventing the spread of the Asian hornet in the area over and above this risk, in the event of a local outbreak. You can download a copy of the instructions here....Make Your Own Asian Hornet Monitoring Trap


Current Legislative Position (Listed on 03 August 2016)
  • This species must not intentionally be brought into the Union; kept; bred; transported to, from or within the United Kingdom, unless for the transportation to facilities in the context of eradication; placed on the market; used or exchanged; permitted to reproduce, grown or cultivated; or released into the environment.
For further queries, you can contact the Invasive Non Native Species (INNS) Team in the Northern Ireland Environment Agency on 028 9056 9558.

Species Related Files:

Invasive Species Ireland

Invasive Species Ireland