Invasive Species Compendium

Detailed coverage of invasive species threatening livelihoods and the environment worldwide

Abstract

Preliminary environmental data on the Asian hornet (Vespa velutina Lepeletier, 1836) (Hymenoptera, Vespidae) in Asturias, Spain.

Abstract

The first sighting of Vespa velutina Lepeletier, 1836 var. nigrithorax du Buysson, 1905, in Spain took place in 2010 in Navarra (Castro & Pagola-Carte, 2010). In 2014 came the first appearance in Asturias. It is an invasive exotic species from Asia. Since then, beekeepers in Asturias face this invasion, being the worst affected agricultural sector. Recently, in February 2018, the Provincial Action Plan was approved and measures are already being taken. This study includes both experimental and bibliographical data on V. velutina, with the intention of producing a preliminary report on the current situation of the invasion in the Principality of Asturias. There is little information regarding the behavior of this species in our ecosystems. The main objective: to broaden our knowledge of the biology and ecology of this hymenopteran in order to be able to act appropriately. There is a close relationship between temperature and the development of the Asian hornet. The worst affected municipalities in Asturias so fare are Llanes, Valdés and Gijón (Figura 15). The high adaptability of queens is very remarkable, and if the optimal climatic conditions are not present, they can even extend the hibernation period (Figura 10). Different factors for involved in the distribution of V. velutina are analyzed in this article, like proximity to freshwater courses and possible attractive plants. Based on the data obtained (Figura 11), in northern Spain queens in the spring seems to have a preference for citrus, garden plants and other fruit trees, and will be found in areas close to rivers, streams and springs. The species also poses a risk to other native insect species, such as the honey bee (Apis mellifera L., 1758) and the European hornet (Vespa crabro L., 1758). Trap data show a higher number of captures of V. velutina (both queens and workers) than V. crabro. Since these are non-selective traps for the genus Vespa, it is suspected that the population of the invasive hornet is outnumbering the population of the native hornet. The population growth of the Asian hornet in the last year has increased considerably, as evidenced by the increase in the number of nests in 2018 compared to 2017. Secondary nests are found mostly in trees ranging from 2 to 20 meters (Figura 16). This is a real threat; quick and effective action is urgent. Trapping work is essential, it is recommended that queen trapping should be done in spring and the trapping of workers should be carried out throughout the summer. The removal of nests is carried out through the entire season, depending on the sightings, the sooner a nest is eliminated the less the hornet's population will grow. In 2017 a larger number of captured specimens was taken in traps placed near nests that had not been removed (Figura 14), so improvements are necessary both in the position of the traps and in the elimination of nests. More scientific research is needed in order to control the species.