Invasive oriental hornet continues its spread throughout Malaga province and threatens native bees and insects

"It's a species that we're no longer going to be able to eliminate, it's here to stay..." This is the pessimistic forecast made by Raimundo Real, professor of zoology at the University of Malaga (UMA), when asked about the disturbing and increasingly abundant presence of the oriental hornet in our streets, gardens and on the beaches. This dangerous, invasive species has continued to spread throughout the Costa del Sol province this year, as the academic expert explained, and also as demonstrated by the data gathered on the removal of nests and swarms by provincial authority's Consorcio Provincial de Bomberos (CPB) fire brigade network.

Calls have come in from all over the province from members of the public asking for the help of specialists to deal with these insects found in their homes, gardens and residential areas. As many as 107 cases have been attended to between June and August of this year, compared to 68 last year. This represents an increase of almost 60% from one season to the next. Not all are due to this invasive species as other wasps and bees are included in the stats, although it is the Vespa orientalis (often listed as "unidentified") that is driving up the numbers, according to the list of fire brigade call-outs consulted by SUR.

"Oriental hornets have already settled in Malaga and, since last year, they have spread further and have now occupied the whole province", confirms this professor of zoology. However, in reality, this year's hornet cycle has been something of an anomaly. Also, if we haven't seen even more specimens buzzing around this summer, it is precisely thanks to the weather conditions this year that have slowed down the population boom for this invasive hornet.

"Their presence has been less dense in spring and early summer because of 'Dana' storms and flooding," says Professor Real. The queens spend the winter hidden in small nests, usually on the ground, so it is possible that overflowing rivers and streams wiped out many of them.

Despite that, many more remained alive and have already managed to form their hives in the ground and in other hidey-holes and the workers have started to emerge from the nests. Their presence is more noticeable these days because worker hornets are now looking for protein in carrion (dead animals) as well as in rubbish. Worst of all, they also prey on native bees.

As Raimundo Real explains, the purpose of this meat is to feed the larvae, since adult hornets only eat fruit. That is why this summer they are being frequently seen near beach bars, searching for scraps on the ground, as well as showing up in rubbish bins. "The first piece of advice is not to leave meat or fish waste in sight, it should always be well-covered."

The greatest harm is caused when they attack bees, which are essential for the ecological balance of all biodiversity. In addition to killing many individual bees, they cause what is known as "fear syndrome" in hives, causing the bees to barricade themselves inside and so they then die of thirst and starvation.

That's not all. Juan Molina, president and veterinarian of Malaga's association of beekeepers, notes that they also catch grasshoppers in large numbers, as well as butterflies, ants and other wasps. "It's a super predator. The white-faced hornet has been studied and found to hunt almost 2,000 species of insects, and this one could be the same or worse."

The solution is difficult to address, although there are options. Firstly, ecological control, by encouraging species that are natural predators, such as the bee-eater, honey buzzard and kestrel that feed on these insects, among other prey. "These are species that specialise in hymenopteran (membrane-winged) insects, so it would be positive to nurture and protect these types of species." Native hornets, such as the European hornet (Vespa crabro), also compete against these invaders and often have an advantage. Furthermore, it is expected that, over time, ecosystems will readjust and other predatory species, such as bats, ants and lizards, will emerge.

Regarding insecticide control campaigns, the professor warns that they are "double-edged swords", because they also affect native species. Therefore, they should only be used when there are concentrations of oriental hornets and it's done under surveillance to prevent the good insects from also falling prey to the poison.

However, the best measure remains the locating and removal of nests. Unfortunately, such tasks are time-consuming and costly, which is why they only step in to do this in urban areas where more people are affected, but not in rural areas. "Local authorities must be notified so that they can send fire brigades or operational services, but it must always be done by specialists because these insects are dangerous."

In reality, these hornets are not usually aggressive, but they do attack when trying to defend their nest. Moreover, they can sting multiple times as they do not lose their stingers and they are so long that a special protective suit is required.

Added to this is the seasonal factor, as Joaquín Becerra, beekeeping technician for the agricultural organisation Coag, points out: "The fight must focus on the moment when it's most vulnerable." When temperatures are milder, at the beginning of spring, the hibernating queen emerges and is responsible for building the nest. For approximately six weeks from the time she emerges, she is alone, collecting cellulose and food for herself and the larvae. "During this time, trapping is the most effective method, as removing a single specimen (the queen) leads to the demise of that nest."

This is why trapping efforts should be focused on early spring as the best time, even though this is the time of year when fewer specimens are seen and they are not particularly bothering people or beehives. "At that time, there is only one hornet, but then, in a few months, each nest will have thousands of workers," says Joaquín Becerra.