The wasp that hunts bees to feed its young is already present throughout Andalusia, and it is not the only one

Andalusia, land of (invasive) wasps. As if the fearsome asian wasp (vespa velutina) and the bicolor hornet (Vespa bicolor), the eastern hornet joins the triad (Vespa orientalis) as the CSIC explains and it has done so in record time: it did not take even six to colonize the eight provinces of the community since its first detection in Algeciras and has already been seen in the Valencia area and on the central plateau. He is reddish, with a yellow face and has a voracious hunger for bees. The question is not whether the eastern hornet is here to stay, but how far it can go.

Habemus new wasp. This invasive wasp native to South Asia, the Middle East and North Africa has been colonizing southern Europe for the last few decades. The first sighting of the eastern hornet dates back to 2018 in Algeciras and since then has settled in urban and agricultural areas throughout Andalusia, although the provinces of Cádiz, Málaga, Seville and Córdoba are the most affected.

The Junta de Andalucía estimates the growth in records between 2023 and 2024 at 30% and it does not seem that it will stop there: an analysis with data from 2024 counted 695 sightings of the species in Spain as a whole. As explains the researcher at the Doñana Biological Station – CSIC Jairo Robla“they are resistant and very competitive species, capable of dealing with everything” and the success of their expansion lies in their great capacity to adapt to new ecosystems.

The habits ofthe eastern hornet. In Córdoba there is a surveillance program that documents the annual biological cycle of the species: appearance of founding queens in mid-March, first workers in June and end of the cycle around November, with nests usually installed in holes in human buildings. From there the colony grows until summer and autumn, which is when there are more wasps. In November the colony almost entirely dies.

This is an omnivorous and opportunistic species: first the queen feeds on plant sources such as flowers or molasses and also hunts other insects such as flies, bees, birds or butterflies, to provide protein for her larvae. Hives are a real feast: an easy way to feed your young.

How to distinguish it from the European wasp. The simplest way is the color: the eastern hornet has a reddish-copper body with two wide yellow stripes on the abdomen, each with two black dots. On the face, a characteristic yellow spot. It measures between 25 and 35 millimeters. The European hornet (Vespa crabro), the only native species of the genus in Spain, is somewhat larger (queens reach 4 centimeters), has a brown thorax and a yellow abdomen with black stripes more marked than that of the eastern one.

Another way to differentiate them is where they nest: while the European hornet usually settles in trees, slopes or natural cavities, the eastern one has a predilection for urban environments, nesting in gaps in facades, blind boxes, roofs or walls, as documented by the IAS-CSIC monitoring in Córdoba. In case of doubt, the IAS-CSIC research team recommends not intervening and contacting the competent municipal services. Early detection of founding queens is essential: eliminating them at this stage prevents the formation of large colonies.

In detail. The map of the expansion prepared by Robla’s team shows a progressive advance from the initial focus in Cádiz towards the interior and south of Andalusia, with Córdoba as one of the provinces where new detections have been recorded in recent years. By the end of 2024, the eastern hornet was already established in all provinces, with doubts only about its definitive establishment in Granada.

To prepare them, they use photos and videos that people upload to platforms such as Observation.org or iNaturalist and subsequent validation by the research team, which allows them to cover a much broader territory.

Map A shows the spread of the oriental hornet (Vespa orientalis). The colors indicate the year of registration: until 2021 (black), 2022 (blue), 2023 (green) and 2024 (red).

Why is it important. That oriental hornets feed on honey bees and other pollinators is a real ecological and economic problem, as warns Robla for Canal Sur: When the density of hornets is high, damage to hives and the biodiversity of nearby areas can be serious.

Selective predation on pollinators can have a cascading effect on agriculture, since crop pollination is reduced, and on beekeeping, a relevant economic sector in Andalusia.

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