Spreading of Vespa velutina in northwestern Spain: influence of elevation and meteorological factors and effect of bait trapping on target and non-target living organisms.
The yellow-legged hornet, Vespa velutina, is a recent invasive species in Galicia (NW Spain). Its invasion has an important socio-economic impact because it preys upon honeybees (Apis mellifera) and other crucial insect pollinators. The dispersal of this species must be monitored to minimise the damage it causes and to take the necessary control actions. The aims of this study were to determine target and nontarget living organisms captured by bait trapping and to compare the distribution patterns of V. velutina and the autochthonous V. crabro. Altitude and weather conditions played important roles in hornet behaviour. The traps placed in low-altitude coastal areas contained the most yellow-legged hornets. In contrast, the autochthonous hornet occurred in relatively greater numbers in the traps hung in high-altitude areas. High minimum temperatures, dew temperature, relative humidity and low maximum temperatures favour the occurrence and spread of V. velutina. These conditions are common in the coastal areas of this territory and promoted the rapid dispersal of this pest. The traps used were not bait-selective, so many other arthropod organisms were captured along with the hornet. Therefore, the use of species-selective baits is required for the ecofriendly effective management of this insect pest.