Last year (8th Sept 2016) I reported on sightings of large numbers of Asian hornets (Vespa velutina Lepeletier, 1836) feeding on flowering bell heather in late August, in Galicia in NW Spain. (1) This year I came across large numbers feeding on Fennel (Foeniculum vulgare) flowers in mid-August; a flower which is exceedingly abundant along, or near the coasts of Galicia.

The Asian, or yellow-legged hornet, Vespa velutina was first introduced into SW France in 2004, probably via shipments of pottery from the Zhejiang or Jiangsu provinces of eastern China (Martin, 2009; Feltwell, 2017). The sub-species introduced into France – and now spreading through Spain, Portugal, Belgium, Italy and Germany – is V. velutina nigrithorax (Perrard et al., 2014). An outbreak of V. velutina occurred in the UK in 2016, but was quickly contained (see Feltwell, 2017; Link 2).

V. velutina is the only hornet (or wasp) in Europe which has an entirely dark brown body with only one orange band towards the end of the abdomen (on the 4th tergite). The photograph (below) shows a close-up of the abdomen.

Vespa velutina was firstly detected on the Iberian Peninsula in 2010, in the vicinity of Amaiur in Navarra, Northern Spain. From there it spread widely in the NE provinces of the Basque Country and Navarre (Lopez et al., 2011). Remarkably, it then somehow jumped across the peninsula to northern Portugal, appearing in some apiaries in the NW province of Minho and in Viana do Castello in 2011 (Grosso-Silva & Maia, 2012). From there it spread northwards into Galicia, arriving in 2012, where it clearly found the region much to its liking. The northern regions of the Iberian Peninsula appear to be particularly well suited to the establishment and spread of this species (Bessa et al., 2016).

Since it first arrived in Galicia in 2012, the wasp has become widespread and abundant, occurring in at least 183 municipalities. (Link 3) The region of A Coruña is among the most affected.  Over 10,200 nests were removed in Galicia in 2016, with the majority (70%) occurring in the A Coruña region (3). The wasp spreads very rapidly, possibly by as much as 100-150 km each year (3). It is often to be seen drinking from streams besides rivers – like the beautiful Rio Sor near Mañón, Coruña  between the provinces of A Coruña and Lugo – and it may use waterways and rivers such as this to disperse.

For reference, the photographs of the Asian hornet feeding on fennel were taken on 15th Aug 2017 at the Hotel Semáforo de Bares (Santa María de Bares, 15337 Manón, La Coruña); and also on 17th Aug 2017 whilst the hornet having a drink was on the banks of the Rio Sor (Ponte Ullo a Refugio Furada, Mañón, Coruña) (below).

Links

1. https://rcannon992.com/2016/09/08/asian-hornet-in-galicia/
2. https://en.wikipedia.org/wiki/Asian_predatory_wasp
3. http://controldeplagassanidadambiental.blogspot.co.uk/2017/04/avispa-asiatica-vespa-velutinas-la.html

References

Bessa, A. S., Carvalho, J., Gomes, A., & Santarém, F. (2016). Climate and land‐use drivers of invasion: predicting the expansion of Vespa velutina nigrithorax into the Iberian Peninsula. Insect Conservation and Diversity, 9(1), 27-37.

Castro L & Pagola Carte S (2010) Vespa velutina Lepeletier, 1836 (Hymenoptera: Vespidae) recolectada en la Penınsula Iberica
Heteropterus Revista de Entomologıa 10, 193–196 (in Spanish).

Feltwell, J. (2017). The arrival of the Asian hornet, Vespa velutina Lepeletier, 1836 into the UK in 2016. Antenna 41(2), 59-64.

Goldarazena, A., Heredia, I. P., Romon, P., Iturrondobeitia, J. C., Gonzalez, M., & Lopez, S. (2015). Spread of the yellow‐legged hornet Vespa velutina nigrithorax du Buysson (Hymenoptera: Vespidae) across Northern Spain. EPPO Bulletin, 45(1), 133-138.

Grosso-Silva JM & Maia M (2012) Vespa velutina Lepeletier, 1836 (Hymenoptera, Vespidae), new species for Portugal. Arquivos
Entomoloxicos  6, 53–54.

Martin, S. (2009). A foreigner in France: The Asian hornet. Biologist, 56(2), 86.

Monceau, K., Maher, N., Bonnard, O., & Thiéry, D. (2015). Evaluation of competition between a native and an invasive hornet species: do seasonal phenologies overlap?. Bulletin of entomological research, 105(4), 462-469.

Perrard, A., Arca, M., Rome, Q., Muller, F., Tan, J., Bista, S., … & Carpenter, J. M. (2014). Geographic variation of melanisation patterns in a hornet species: genetic differences, climatic pressures or aposematic constraints?. PloS one, 9(4), e94162.