The European hornet Vespa crabro L., ♀ 30-40 mm long The Asian hornet Vespa velutina Lepeletier, ♀ 25-30 mm long The Oriental hornet Vespa orientalis L., ♀ 25-35 mm long A New Enemy of Honeybees in Europe: the Asian Hornet, Vespa velutina AGNÈS RORTAIS, CLAIRE VILLEMANT, OLIVIER GARGOMINY, QUENTIN ROME, JEAN HAXAIRE, ALEXANDROS PAPACHRISTOFOROU & GÉRARD ARNOLD  References ONO M, IGARASHI T, OHNO E, SASAKI M (1995) Unusual thermal defence by a honeybee against mass attack by hornets. Nature 377: 334-336. PAPACHRISTOFOROU A, RORTAIS A, ZAFEIRIDOU G, THEOPHILIDIS G, ARNOLD G (2007) Smothered to death: hornets asphyxiated by honeybees. Current Biology 17: R795-R796. PERRARD A, HAXAIRE J, RORTAIS A, VILLEMANT C (2009). Observations on the colony activi- ty of the Asian hornet Vespa velutina Lepeletier 1836 (Hymenoptera: Vespidae: Vespinae) in France Annales de la Société Entomologique de France 45: 119-127. TAN K, RADLOFF S, LI J, HEPBURN H, YANG M, ZHANG L, NEUMANN P (2007) Bee hawking by the wasp V. velutina on the honeybees Apis cerana and A. mellifera. Naturwissenschaften 94: 469-472. VILLEMANT C, HAXAIRE J, STREITO J-C (2006) Premier bilan de l’invasion de Vespa velutina Lepeletier en France (Hymenoptera, Vespidae). Bulletin de la Société Entomologique de France 111: 535-538. Honeybees are essential pollinators of crops. In Europe, important pollinator declines have been reported, which jeop- ardise pollination services in agricultural ecosystems and have great economic impacts. The recent accidental introduc- tion of the Asian hornet Vespa velutina into Europe (south-west of France) (Villemant et al. 2006) represents a new threat to pollinators, mainly honeybees. The Asian hornet V. velutina is natu- rally distributed in mountainous regions from northern India to the Indochinese Peninsula, Taiwan and Indonesia. In 2004, the form nigrithorax, was record- ed, for the first time, in France (Lot-et- Garonne district), and has spread in 4 years across 20 districts, over approxi- mately 120,000 km² (Figure 1). As demonstrated by the rapid growth of colonies (Figure 2), the spe- cies has adapted perfectly well to its new environment so that eradication is no longer possible. If no rapid and effi- cient control management is conducted, further expansion is expected to occur, in the near future, into other European countries where the hornet can find suitable environmental conditions (cli- mate and resources) to develop. At present, and with this new spe- cies record, a total of three hornet spe- cies are found in Europe: the European hornet (V. crabro) widely distributed all over Europe, the Oriental hornet (V. orientalis) in south-east Europe, and the invasive yellow-legged hornet (V. velutina) in the south-west of France (Figure 3). The three species are mor- phologically distinct (colour and size), and while they are strongly attracted to honeybees, their impact on them may not be equal. Vespa velutina may be more competitive than V. crabro and V. orientalis because of the larger size of its nests and colonies. Hornets attack honeybee colonies (Figure 4) to feed their brood with proteins, and to get carbohydrates (honey). In Asia, native honeybees have developed effi- cient strategies to defend their colonies. For example, when attacked by the giant hornet (V. mandarinia) or the yel- low hornet (V. simillima), the eastern (A. cerana) and dwarf (A. florea) honey- bees form a ball of workers around the intruder and kill it by heatstroke (Ono et al. 1995). In Europe, while native honeybees display the same balling behaviour, the underlying mechanism by which they kill their predator is dif- ferent. For example, in Cyprus, honey- bees (A. m. cypria) kill the hornet (V. orientalis) by asphyxia (Papachristoforou et al. 2007). However, native European honeybees (e.g., mellifera, ligustica, carnica ssp.) may not be able to compete with the new invader (V. velutina), as con- firmed by observations made in the field on A. mellifera and V. velutina: in France, V. velutina feeds predominantly on hon- eybees (Perrard et al. 2009), and in Asia, introduced A. m. mellifera colonies exhib- it ineffective defence strategy against attacks of V. velutina (Tan et al. 2007). In a context of globalization and global warming, the threat of invasive species that may impact on honeybees in the same way as hornets is expected to increase, as demonstrated by the recent accidental introduction of V. orientalis in Mexico. To limit the intro- duction and spread of such invasive species, a joined action is required at both European and global levels, such as the setting-up of an alert network. Figure 3. Hornets’ distribution in Europe (dimensions refer to queens' size). Photos: J. Haxaire (two top photos) and Alexandros Papachristoforou (bottom photo). ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e ! e 2004 0 100 km 2005 2006 2007 c ! e ! A FRANCE Paris ! e a 2004 2005 2006 2007 b Figure 1. (A–B) Records of the presence of V. velutina in France from 2004 to 2007 (area limits represent districts). (C) Detailed map of the distribution of nests in the south-west of France. Figure 2. Nests of Vespa velutina: embryo (top) and mature (bottom) from 5 cm in diameter up to 1 m high and 80 cm wide within 6-7 months. Photos: J. Haxaire. Figure 4. Vespa velutina attacking a honeybee colony. Photo: J. Haxaire. A NEW ENEMY OF HONEYBEES IN EUROPE: THE ASIAN HORNET, VESPA VELUTINA 181 1 cm 20 cm