Experts warn that the number of Oriental hornets will increase in the fall

Experts warn that the number of observations of the Oriental hornet will increase this autumn in Slovenian Istria. According to Simon Golob from the Beekeepers' Association of Slovenia, citizens have reported more sightings of this invasive species in recent fourteen days. For now, these are mostly individual specimens, as their nests are usually well hidden. Golob emphasizes that the Oriental hornet is considered native in parts of southern Europe and thus not listed among invasive alien species. However, he warns that continued hot and dry summers could cause increasing problems even in the Primorska region. “It isn’t as invasive as the Asian hornet, but if such weather conditions continue, the entire southern part of Primorska will be severely affected,” he says. Most reports this year come from Koper, where one nest was discovered last year in one of the kindergartens. The nests are hidden in walls, gutters, and ground. “Throughout the summer we will monitor carefully. I expect the situation to be worse than last year by autumn. If we don’t act, the species will spread further,” Golob warns. What to do if you spot an Oriental hornet? The Oriental hornet can be identified by its reddish body and distinct yellow band on its rear. An individual specimen is generally no more dangerous than other types of hornets, but the nests they build in the ground, walls, gutters, or other hidden corners present a challenge. If you notice multiple individuals in the same area or suspect a nest, do not approach or remove it yourself. Report the sighting to local authorities, who will soon publish guidelines for reporting. Experts emphasize that early detection and destruction of nests are the most effective ways to limit the spread of this invasive species. According to Golob, systematic destruction of nests is particularly effective, although these nests are often hard to find. The Oriental hornet typically nests in the ground, walls, and gutters, leaving their habitats largely unnoticed. How to distinguish between European, Oriental, and Asian hornets? Urban areas are most suitable for them. Although our climate is not ideal for them, Oriental hornets find favorable conditions in densely built urban areas. “In cities, due to heat-retaining surfaces, it’s warmer, making survival easier. Last year, all found nests were discovered in settlements, with the most specimens found in Plava and the central part of Koper. In broader rural areas, we almost didn’t detect any,” explains Golob. The weather conditions this year also suit their development. “They prefer heat, while last year's rainy weather was less suitable for them,” he adds. He notes that experiences from Spanish Malaga show that the species initially spreads through city centers and along the coast, posing the greatest challenge when nesting near humans. Currently, they are hunting insects, and autumn attracts fruit. During this time of the year, the Oriental hornet primarily seeks protein-rich food. They prey on various insects, including pollinators and bees, and also feed on organic waste and decaying matter. In autumn, their feeding habits change as they need more energy for the development of their queens. At that time, they are attracted mainly to sweet fruits, especially grapes, which are abundant in autumn. The City of Koper is preparing guidelines for residents. As explained, together with the Inter-Municipal Service for Environmental Protection, Rescue, and Conservation and the Beekeepers' Association of Slovenia, they are preparing guidelines for managing the situation. The Oriental hornet “We are aware of the issue and therefore jointly preparing measures. Information on which service citizens can contact upon observing an Oriental hornet or its nests will be published in the coming days,” announces the City of Koper.