PROJECT DESCRIPTION
BACKGROUND
The Asian hornet (Vespa velutina), or yellow-legged hornet, is an invasive alien insect species that poses a serious threat to European biodiversity, due to its predation on native wasps, bees, and other insects of the species Hymenoptera, Diptera and Lepidoptera. In addition to its impact on native insect species, the Asian hornet, which is an Invasive Alien Species (IAS) of Union concern (Regulation EU 1143/2014), can also cause serious impacts on honey bees and pollination services, and can be a nuisance when nesting in urban areas. The species invaded Italy in 2012, and by 2015 it had colonised a wide portion of Imperia district (western part of Liguria), while a low-density population has established in Cuneo district (southern part of Piedmont). The species is being controlled in France through the use of baited traps and the destruction of nests. However, these methods have proved to be inadequate and the species has spread to most of France and other European countries, including Italy.
OBJECTIVES
The main objective of LIFE STOPVESPA was to contain the spread of the Asian hornet, (Vespa velutina) in Italy. The project aimed to develop a prototype for early location of nest positions, and to establish a monitoring and control system limiting the spread and impacts in those areas already affected in Liguria and Piedmont. Specifically, the project aimed to: develop a harmonic radar system to track flying wasps when returning to their nests, particularly to locate hidden nests early in the season so they can be destroyed before new queens are created; remove all colonial nests present in the invaded area (western Liguria and southern Piedmont) and those that may be established during the project; implement an Early Warning and Rapid Response System at the regional and national level to prevent further invasions; and create a coordinated coalition of trained volunteers among beekeepers to detect and destroy colonial nests.
RESULTS
The LIFE STOPVESPA project strongly contributed to the containment and control of the invasive alien Asian hornet (Vespa velutina) in the Liguria and Piemonte regions, and prevented it from spreading further in Italy.
The Asian hornet’s rate of spread decreased from 18 km/year before the beginning of the project to about 3 km/year at the end of the project. The colonisation rate in the western part of Liguria also decreased, from 310 km2/year to 110 km2/year. Moreover, the distribution of nests detected in the final year of the project confirmed the containment of Vespa velutina (98% of the detected nests in the Liguria region were located in areas already colonised by the species in 2015). This spatial containment was achieved thanks to the establishment of a monitoring network of beekeepers, citizens and local authorities. The network of beekeepers at the start of the project constituted 40 bottle traps, whereas in the last two project years it increased to 1 691 bottle traps positioned in 914 monitoring sites.
The project team developed new tools for the management of the species, namely two harmonic radar prototypes able to track the hornets and detect nest locations, even those concealed by vegetation. These prototypes allow for real-time tracking of the flight of the hornets in complex environments, with a maximum detection range of 500 m from the radar. The two prototypes were efficient both in invaded areas and for new outbreaks.
A total of 2 205 nests were detected during the project implementation. Of these, 1 871 nests (85%) were directly removed thanks to the project’s strategy, which involved the project’s monitoring and destroyer teams together with the collaboration of Civil Defence Teams. Nest removal was calculated as saving 76 million honey bees and native insects, since timely nest destruction prevented the predation of these species by Vespa velutina workers. The large number of saved insects generated benefits in terms of ecosystem services, especially biodiversity protection (e.g. Italy is considered an important hotspot of bee biodiversity), plant pollination, and honey production.
The project team developed an effective Early Warning Rapid Response System, which was based on a widespread surveillance network able to quickly detect the presence of the species, with the involvement of beekeepers and their associations; strategies for the control of the species in new outbreaks (e.g. rapid nest detection and destruction; trapping networks); and strategies and procedures for the management of the species in the colonised areas. A Vespa Emergency Team (VET) was activated and constantly monitored information on Vespa velutina in Italy.
The project team contributed to the drafting of the Italian ‘National Action Plan on Vespa velutina’. The procedures in this Action Plan are being implemented by the Italian Ministry of Environment.
Among the project’s dissemination activities were the production and distribution of 10 000 brochures, 33 000 leaflets and a documentary film; the organisation of about 60 events (e.g. for beekeepers); participation at 39 conferences; publication of 9 scientific papers, organisation of 8 training courses/workshops, and school activities involving 1 140 students.
In areas with intensive beekeeping activity, Vespa velutina concentrates its predation on honey bees. The project team estimated the quantity of honey in theory produced by bees that were not preyed upon as a result of the project’s activities: from 34 tons to 115 tons. Assuming that 1 kg of honey has a mean commercial value of about €5, it could be estimated that the removal of Asian hornet colonies prevented an impact on honey production of between €172 000 and €573 000.
In the four years, 30 people were directly employed by the project, full-time or part-time. The project also had positive social effects, because the hornet frequently builds nests in urban areas, alarming citizens. Hidden nests have led to deaths in France and Spain, and accidents have also occurred in Italy (without fatal consequences). The project’s strategy allows citizens to report cases, which are acted on by nest destroyer or Civil Defence teams.
Further information on the project can be found in the project's layman report and After-LIFE Conservation Plan (see "Read more" section).
